ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: sillysmile on September 12, 2010, 04:31:08 pm
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Hey there, I have created this question thread, because I am preparing my Unit 4 Biology notes, and intend to ask various questions in subsequent weeks. It's much simpler then multiple threads. If anybody else wishes to ask their own biology-related questions feel free to post them here. :D
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Okay, so I'm going to get right into it.
1. How can DNA be produced from messenger RNA, by using the enzyme reverse transcriptase?
2. What is the purpose and method of Genetic Transformation? Is it just another term for Recombinant DNA Technology?
thank you :)
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1. To make DNA you need a DNA polymerase. In our cells we only have DNA polymerase that works on DNA - we call it DNA dependent DNA polymerase. However, some organisms (viruses) have polymerases that are capable of making DNA from RNA. It doesn't necessarily have to be mRNA, but we call these enzymes "RNA dependent DNA polymerase".
So the name "reverse transcriptase" is a general term for those enzymes that allow us to go against Crick-Central dogma and produce DNA from RNA.
2. Genetic transformation is where DNA (usually fragments of DNA) is taken up by a cell and incorporated into the genome. It usually happens in bacterial cells, where they're capable of transporting environmental DNA across their cell wall and expressing it. It's not a synonym for recombinant DNA technology, which is where we combine two (or more) sequences of DNA, typically via restriction enzymes and plasmids.
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COOL STORY ALERT: I got spammed by TSFX the other day being like DON'T WRITE OUT YOUR NOTES OR YOU WILL FAIL, BUY NOTES AND LECTURES FROM US. Because I accidentally joined their mailing list for 2010 VCE (make it stop, they continuously send me crap).
And I was like 'lol, okay TSFX, because clearly that is the case'.
I spent like a month preparing my notes and no time involved with TSFX and I have clearly failed at life and am now living on the streets and stuff.
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but they have a point there, you will fail year 12 if you don't use their notes. Nah jks, hahahaha!! that's hilarious...
seriously though, people are freaked out enough by the end-year exams as it is.
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COOL STORY ALERT: I got spammed by TSFX the other day being like DON'T WRITE OUT YOUR NOTES OR YOU WILL FAIL, BUY NOTES AND LECTURES FROM US. Because I accidentally joined their mailing list for 2010 VCE (make it stop, they continuously send me crap).
And I was like 'lol, okay TSFX, because clearly that is the case'.
I spent like a month preparing my notes and no time involved with TSFX and I have clearly failed at life and am now living on the streets and stuff.
Its funny cos in unit 3 they sent me this list of questions for each subject and said "IF YOU DONT KNOW THESE QUESTIONS YOU NEED TO GO TO TSFX (something in that nature)." I read half the questions and most of them were irrelevant to the study design at all or were very obscure and unvcaa like..
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TSFX is actually a joke imo (but no offence to people who go - it works for some people but lectures never usually work for me).
Therefore, it is easy to assume how much I enjoy learning in a University environment.
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Therefore, it is easy to assume how much I enjoy learning in a University environment.
Oh you're just going to love next year if you transfer.
Anyway, I want more biology questions! I got all excited when I saw new posts in here :P
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Great! Love your exuberance :)
So here's a quick one to confirm for me: The non-coding strand (template strand) is complementary to the coding strand and also the mRNA molecule. The tRNA anti-codon is complementary to the DNA coding strand or is the equivalent of the DNA template strand in RNA language.
E.g. the DNA non-coding strand is TAA
the mRNA triplet is AUU
the tRNA triplet is UAA
Both Insight and Lisachem have stuffed this up in their exams and it really irked me. So I'm just making sure that my understanding is correcterino.
Cheers :)
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Yeah.
That's probably the most confused part of genetics, because some resources use "template" to mean "coding"...
I just remember that coding = what we want = mRNA and then work the rest out from that. I don't think you'd really need to worry about the tRNA being complementary to the original DNA strand, just worry about how it relates to mRNA and the ribosome.
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Okay cheers for that :)
And LOL at my tRNA association - I was just being ultra descriptive for some reason. I'm not worrying about it :)
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yep thats right... but i would use the word template and nontemplate strand... just makes it easier i guess
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Therefore, it is easy to assume how much I enjoy learning in a University environment.
Oh you're just going to love next year if you transfer.
Anyway, I want more biology questions! I got all excited when I saw new posts in here :P
I know right, I sit in Psychology and that guy tries to explain QM things and I am like 'dude, I studied this for two years and I still have no idea what you are saying right now'.
Contribution: template and nontemplate ftw.
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okay, what exactly is a barr body? and what is its purpose?
thank you :)
also, could somebody explain the blebs that are formed during apoptosis?
ty
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Great! Love your exuberance :)
So here's a quick one to confirm for me: The non-coding strand (template strand) is complementary to the coding strand and also the mRNA molecule. The tRNA anti-codon is complementary to the DNA coding strand or is the equivalent of the DNA template strand in RNA language.
E.g. the DNA non-coding strand is TAA
the mRNA triplet is AUU
the tRNA triplet is UAA
Both Insight and Lisachem have stuffed this up in their exams and it really irked me. So I'm just making sure that my understanding is correcterino.
Cheers :)
Just make sure you call the DNA a triplet, the mRNA a codon, and the tRNA an anticodon. :)
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stonecold's right, VCE is all about irritating details :S
Barr bodies require a bit of background to understand. They're a phenomenon that result from the process of X-inactivation. In humans, our sex chromosomes have two possible arrangements: XY or XX. Since an XX individual (woman) would have MORE X chromosomes than an XY individual (man), the hypothesis is that one of them is deactivated in order to prevent such an imbalance. The deactivated chromosome forms a "Barr body" and usually sits at the edge of the cell as a thick, dense bundle of chromatin. It has no actual biological "purpose" or function.
It's probably unnecessary for you to know the actual process by which it deactivates, but you should know that all but one X chromosome are deactivated. So if an individual had an aneuploidy (say XXXX), you'd expect three barr bodies to be present in all cells. What would you expect to observe in a man with Klinefelter's syndrome? Finally, the process of inactivation is random - during embryological development the chromosome to be deactivated is randomly selected in each cell, which leads to something called "atypical lyonisation". This means that women can be a chimaera of different alleles based on which ones are deactivated in which part of the body.
Random fact one: think about why almost all tortoiseshell cats are female...it's got to do with atypical lyonisation :P
Blebs in apoptosis: as the cytoskeleton of the cell is broken down, the integrity of the membrane is lost. As such, it can form random invaginations or bulges. This is the process of blebbing, since a bleb is a bulge that will eventually separate entirely from the cell to form an apoptotic body.
Random fact two: since UV light induces apoptosis, it increases the amount of apoptotic bodies in circulation. Since, Lupus patients have "anti nuclear antibodies", UV light exacerbates their condition by increasing the amount of nuclear material circulating through the body.
Sorry for all that, it's just that Xinactivation is probably my favourite thing in genetics and I went off on a bit of a tangent.
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awesome explanations yet again... do you happen to be a biology teacher?
ty
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No, but I wish I was. I'm just a student procrastinating over writing my lab report.
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well, you certainly know your stuff! but maybe spend some more of that biological knowledge for your own best interests instead of other peoples.
okay question 1. : are short tandem repeats present in ribosomal RNA?
2. : what exactly are spacer regions and which types evolve the quickest?
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I'm on break right now, I have spare time.
1. Don't actually know for sure, but if they're present in the DNA that codes for the rRNA then they'd be transcribed into the rRNA
2. Never heard of them evolving, but they sit between genes as a buffer and aid transcription
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yeah, it's all good Russ :)
in regards to 2. yes apparently spacer regions are sequenced to compare different species, and different types of spacer regions have a quicker average rate of mutations (thus evolve quicker) but it's just a bit confusing
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Are you just seeking this for your general knowledge because you totally don't need to know anything about whether ribosomal RNA has short tandem repeats.
I maintain that you need to know about parallel evolution though.
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well, I guess it's partly for general knowledge, but it's actually because I was reading Edmunds notes and he mentioned something that sounded like short tandem repeats, and that it was a large component of rRNA. If I don't need to know that, then it's a benefit.
It's interesting that you mentioned parallel evolution, I gather you know that it's now out of the study design. Regardless I don't think parallel evo is too difficult to understand .
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Most of rRNA is repeated/palindromic sequences (think about its tertiary structure), which might sound like STRs
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are races and sub-species the same thing?
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Not really. One of them (sub species) is part of taxonomical classification, whilst the other (race) isn't. Race is more of a social construct, biologically there's more difference "within" a race than between them.
You can use them synonymously without anyone caring, but technically they're probably different.
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Describe the interrelationship between biological, cultural and technological evolution.
(technological ie. ART - eg. IVF)
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well, I guess with the biological evolution of brain size and the muscles allowing speech, communication was possible. This ability to communicate allows the species to pass down information through the generations (e.g. burials) and gradually information is added/lost/altered, (this is cultural evolution). I'm not so sure about technological evolution but it's passed down tthrough generations, and woudln't be possible without the the intial biological evolution and also cultural evolution. Aight, so a lot of this was guesstimations, but it makes sense ;)
If any details are incorrect, please feel free to correctify!
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ive got a question---
Im a bit confused about the classification of hominids /hominin since Nature of Biology seems different to VCAA, Is there a source where VCAA has updated the study design for this particular bit, cuz ive heard these classfications are ever changing due to constant discoveries/
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"When studying hominid evolution (eighth bullet point page 28 study design) students will encounter the term hominin and when answering relevant questions on Examination 2 will be expected to be familiar with and use both terms correctly as outlined below.
The taxonomic family Hominidae refers to the great apes (chimpanzees, gorillas and orangutans) and includes humans. Hominin refers to modern and extinct humans and their erect-walking ancestors including, for example, Australopithecus , Kenyanthropus and Homo genera. Under some older taxonomic classifications, hominin is used instead of hominid to refer to humans and humanlike ancestors and to describe the early humans now called Hominins. When the classification system changed to include apes in the human lineage (Hominidae), the term Hominid came to include apes and humans.
The term Hominin is used today, when talking about the human lineage and its ancestors. These changes in taxonomy have arisen from fossil, biochemical and genetic data. For further information: www.amonline.net.au/human_evolution/about.htm"
From VCAA.
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yeah cool thanks, apparrently, theres a differentiation now betweeen australopithecus species, they've introduced a new one calle paranthropus, of which there is no mention in Nature of BIo. Just read that ammendment . VCAA released a paper on this topic recently ifanyone's interested just google it.
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IF PLANNING TO DO THE AUSTED EXAM AND DON'T LIKE SEEING QUESTIONS DON'T READ THIS.
(http://i52.tinypic.com/4t3d4j.png)
The answers list B and A respectively. However, although it is more likely to be X-linked (not directed to answer for the most likely in question) D and C are also correct. Can someone please confirm this and or point out some obvious mistake that I made? Thanks.
Also, what would your answer for this be and please tell me that these are stupid options:
Question 22
Fossils in the genus Australopithecus are thought to represent branches on the tree of life intermediate between apes and humans because:
A. They show many features that are intermediate between apes and humans
B. They show a mixture of the features of apes and humans
Cheers.
EDIT 3: THE F##K'S SAKE EDITION
Also these questions which are not good at all. I'm getting angry at the answers. So before I disclose them I want to know what people would say:
The forelimbs of birds and bats are:
A. Homologous
B. Convergent
C. Analogous
D. Both analogous and convergent
Question 24
Which of the following does not come under the category of genetic drift?
A. The founder effect
B. The bottleneck effect
C. Sexual recombination
D. Gene flow
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Your photo isn't loading, switch it from google hosting to a proper photohost (tinypic or imageshack etc.) and I'll answer that.
For 23, the forelimbs are analogous structures but examples of convergent evolution, which suggests D. Depending on how literal the question is, it could conceivably be C.
For 24...I really need to go check if gene flow is part of drift or independent of it, but I'm thinking C
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Thanks Russ.
Ahh yeah will do right now, thought it worked because it was displaying for me.
I agree with you Russ. I put analogous and convergent and they had homologous which is clearly wrong considering they are of different classes. Besides are we expected to know that bats are mammals and birds aves?
Also, for 24, they have the answer as D but I am 98% sure it is recombination (which can clearly result in drift because of its randomness).
Don't know if you missed it, but how about 22?
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I see no way in which they're homologous, I agree that A is wrong unless I'm missing something pretty major. Can't speak for whether or not you need to know it, but the birds/bats thing is a pretty typical example so I suspect it might be on the design somewhere.
In that case I'll actually go find last semester's notes (not doing population genetics again till next year). It's possible that since recombination is a random event, that classifies it as drift...bit of a sneaky question if so.
I skipped 22, the two options confused me since I was taught that either would be suitable. Maybe someone else can help with that.
For the pedigree: even though the question doesn't specifically say that you have to nominate the most likely, you always do. When answering pedigree questions, it's always theoretically possible that a trait that skips a generation could be dominant (eg spontaneous mutation arose). Because of stuff like that, you're always working out which mode of inheritance is most likely.
Assuming you meant q8, C is incorrect, it can't be X-dominant or I-4 would need to be affected. D is plausible, but less likely due to the 2:1 ratio of men:women affected.
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Yeah I agree 100%. They are wrong.
I was also thinking that either could be correct for Q22 so don't worry about it.
For the pedigree I definitely agree that I should have circled sex-linked (I somehow disproved it, in the timed exam), but I trust VCAA to have a pedigree with only one inheritance mode or make it clear that there may be a more likely option in the exam.
Yeah for Q8 C is definitely incorrect.
As always the study designs are ambiguous as ever so it's hard to know exactly what they want of us, although it's my opinion that specific examples are usually not needed for VCAA exams because enough information is always present in the stem of the question.
There are even more errors going through the answers, but I won't bother you with them. Thanks for your efforts anyway, always appreciate your readiness to help:
And to anyone wanting to do this exam - don't do it; it sucks.
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These are from LisaChem 2007. Not too sure of their answers.
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Here are the answers :)
Unless you thought the answers were wrong?
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yeah, i thought they might be wrong :S
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don't quote me but im pretty sure the answer for that one is d
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don't quote me but im pretty sure the answer for that one is d
They say A. I personally thought that they were all wrong.
Wouldn't the genotypes be ABE abe ABe abE ?
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Question 7 - I'm not sure about: I find that stuff very confusing.
But question 3, I am 100% sure that all answers are wrong.
EDIT: Haha, just noticed that I wrote "question 7" twice.
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oh hang on yeah it would be A. i'm not gonna bother explaining it cause i will totally stuff it up but remember the "A/a" aren't swapped over and i think that's how you got your answer that you just wrote
they've also put the possibilities written in answer A in a different order to make it more confusing (logically the second and third combos should be switched around)
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How is A right? Doesn't that represent crossing over which has occurred between alleles A/a and B/b ?
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How is A right? Doesn't that represent crossing over which has occurred between alleles A/a and B/b ?
Yes.
Your original list (ABE/abe/ABe/abE) was correct, none of the options for that MCQ are right
e, might just mention if something like 3 comes up in an exam, you can cross out anything that has thymine in it (in that case you would eliminate A/B/C straight away :) )
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woops sorry guys.. just ignore me :]
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To what extent do we need to understand Geological time and the eras/periods/epochs etc.
Thanks
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To what extent do we need to understand Geological time and the eras/periods/epochs etc.
Thanks
I m pretty sure they give us any information of that sort in the question, at least that hasbeen from my experience.
Another question
Some of these answers in external company exams, say gondwana instead of pangea, which one should we refer to.
Our teachers said to say Pangea, but Gondwana has been used alot . But isn't gondwana the souther mass continent, the Earth was broken into two, and Laurasia was the Norhern one?
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Yeah thats how i've learnt it
Pangaea (super continent)
separates into:
Gondwana = southern (africa, antarctica, nz, aus, south america, india)
Laurasia = nortern (north america, europe, asia)
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cheers mate
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Do extranuclear genes include ribosomal RNA?
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Wouldn't think so. rRNA structure is determined by nuclear DNA anyway, right?
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Do extranuclear genes include ribosomal RNA?
Not in eukaryotes. No idea about prokaryotes, can't remember last semester :P
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Well they can't have extranuclear genes if they don't have a nucleus... Or they would all be extranuclear.
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This is from CSE 2008 btw...
It is these two questions which are confusing me. I know that the cytoplasm for a zygote comes from the mother, but I don't get why A is wrong for Q12.
And Q23, why doesn't disabling the apoptosis protein stop autoimmune diseases?
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Q12 - A is wrong because ribosomes do not carry genes. B is correct because the mt.DNA comes from the egg.
Q23 - The answer should be D. The immune system is not reliant on apoptosis for eliminating material it is recognising as non-self.
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Well they can't have extranuclear genes if they don't have a nucleus... Or they would all be extranuclear.
Sleep deprivation is doing strange things to me, I associated extranuclear with plasmids for some weird reason.
I suppose it's worth noting that for q12, it's rare for male organelles to be transferred but it does happen
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Stop helping us and get some sleep Russ! :) Really, you help us too much.
Re. Q12 that's interesting to know. Love hearing things in Biology that make you realise that in life there are almost always exceptions and nothing is uniform.
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I'll sleep after exams, plenty of time then right? Nah, I love biology, I'd teach it professionally if it was a realistic option for me.
Anyway, I had a poke around with rRNA and the mitochondrion and apparently it does encode part of it, specifically here
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Hmm so the mitochondrion has a gene which codes for rRNA but the rRNA itself does not have any genes?
Haha, that's the spirit! What are you planning on doing?
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you need apoptosis to get rid of autoreactive T cells in the thymus and in the periphery. so if you shut off apoptosis you can't get rid of these cells so they stick around and if they become activated and proliferate and can't die then you will probably get autoimmune disease... so yeah i would say D too
genes encode the rrna ... the rna itself is not a gene it is a product of a gene
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thanks everyone. sleep deprivation is killing me right now sorry...
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then you will probably get autoimmune disease... so yeah i would say D too
Yeah, agree
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This is from STAV 08
For question 1c) , I don't really get how they arrive at the conclusion that only XBY and XbY will survive. I see it says that recessive pollen is not viable, but then how do you end up with an XbY
Also, how do you know which chromosomes are going to pair with which in meiosis for question 2c? Don't you need to know to work out the combinations of gametes?
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Okay. The female's genotype is XBXb, meaning she can produce the gametes XB and Xb. The male's genotype is XbY, so it would produce the gametes Xb and Y, but its Xb gametes do not survive (as stated in the stem of the question). It would have only "Y" viable gametes.
Hence the offspring can have genotypes XbY or XBY, but not XBXb or XbXb.
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I get the feeling I was supposed to know that pollen means male yeah?
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Yeah I would think so. I think there's a tipoff in that it uses the term "ovules" for 2b
2c is a little cheap.
Basically, when you get a translocation like that the altered chromosomes pair to make "whole" complements. Numbering left to right, one to three, #1 would go with #3 and #2 would be by itself. I hope :P
What's throwing me is the fact that they've deleted the other material, which I wasn't aware would happen. If you want to do some reading, go here to section 5.2.3.2
Diagram 5.3 shows the standard "cross" method of pairing at meiosis, where you get adjacent/alternate segregation.
This sort of stuff has a LOT of complex layers underlying it, there are plenty of extra things that complicate translocation pairing
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Yeah I would think so. I think there's a tipoff in that it uses the term "ovules" for 2b
2c is a little cheap.
Basically, when you get a translocation like that the altered chromosomes pair to make "whole" complements. Numbering left to right, one to three, #1 would go with #3 and #2 would be by itself. I hope :P
Okay, so they are clever and kind of know how to overcome the defect lol. Still some of the gametes are abnormal though...
This was a question from the same exam. I just want to know how B is wrong.
According to Wikipedia, "Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species"
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I added a whole lot of stuff to my post, check it out.
For a start, wikipedia is wrong, or at least not exactly right (typical). Polymorphism occurs when there are two or more alleles present in a population, where the rarest allele is at a frequency higher than can be explained by mutation alone. The presence of multiple phenotypes is not sufficient to define polymorphism. Furthermore, I'd say that polymorphic refers more to a specific allele rather than to the overall expression of a trait (ie at more of a genetic level than a phenotypic level)
The trait is clearly polygenetic and if B had replaced "polymorphic" with "polygenetic" it would be correct. What was the correct answer, C? (not sure between C or D)
edit, i just checked the wiki page, if you scroll down to "genetic polymorphism" it does have the correct definition, albeit one that's worded terribly
Since all polymorphism has a genetic basis, genetic polymorphism has a particular meaning:
* Genetic polymorphism is the simultaneous occurrence in the same locality of two or more discontinuous forms in such proportions that the rarest of them cannot be maintained just by recurrent mutation.
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Thanks Russ. For the multi choice, they said D...
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Okay, this is probably an example of unnecessarily pedantic examiners. The question states that it's a wide range of colours but never says that they're continuously distributed (which is an assumption you would make given the trait).
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quick question: what is the role of ribosomal RNA within a cell?
thanks
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It's a structural component of the ribosome - it helps "read" the mRNA.
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this might sound like an ignorant question, but are the X and Y chromosomes a homologous pair?
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this might sound like an ignorant question, but are the X and Y chromosomes a homologous pair?
For the purpose of meiosis, yeah. And also, the Y chromosome has some homologous regions with the X chromosome. i.e. It has some of the same genes. These regions can undergo crossing over with the X chromosome, but I don't think we are required to know it.
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Nah very fair question. They are :) But they do not form a chiasma because different genes are held on them.
Hmm interesting stonecold :)
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this might sound like an ignorant question, but are the X and Y chromosomes a homologous pair?
Yes, in theory. They pair during meiosis but don't have the same loci. You'll get different answers depending on which textbook you read, but I think of them as homologous
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I'm pretty sure I've seen VCAA refer to them as homologous but don't quote me on that.
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wow, awesome to know guys ;)
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Nah very fair question. They are :) But they do not form a chiasma because different genes are held on them.
Hmm interesting stonecold :)
It was in the 2008 NEAP exam IIRC.
They are called pseudoautosomal regions.
http://en.wikipedia.org/wiki/Pseudoautosomal_region
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Oh okay. Far out, although it's nice to know, it annoys me that these things are included on exams geared towards VCE students, clearly not necessary.
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also, what are the satellite endings on chromosomes, and how are they relevant to the karyotyping of chromosomes?
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Oh okay. Far out, although it's nice to know, it annoys me that these things are included on exams geared towards VCE students, clearly not necessary.
The translocation Q in STAV 2008 left me with no idea about what to do... They really do go too far sometimes.
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Nah very fair question. They are :) But they do not form a chiasma because different genes are held on them.
Hmm interesting stonecold :)
It was in the 2008 NEAP exam IIRC.
They are called pseudoautosomal regions.
http://en.wikipedia.org/wiki/Pseudoautosomal_region
the NEAP exams, always seem to have information which is slightly out of the area of information that we need to know.
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Oh okay. Far out, although it's nice to know, it annoys me that these things are included on exams geared towards VCE students, clearly not necessary.
The translocation Q in STAV 2008 left me with no idea about what to do... They really do go too far sometimes.
but, I believe that translocation could actually come up in the biology exam
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also, what are the satellite endings on chromosomes, and how are they relevant to the karyotyping of chromosomes?
They're just differently dense regions of chromatin, so they stain slightly differently and thus can be used to determine chromosomes for karyotyping. Seriously doubt you need to know that.
The translocation Q in STAV 2008 left me with no idea about what to do
If that was the one you posted, then there's no way it'll come up. You need to know what a translocation is, not the mechanics of a cross with altered chromosomes (they suck)
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If that was the one you posted, then there's no way it'll come up. You need to know what a translocation is, not the mechanics of a cross with altered chromosomes (they suck)
Yeah, it was that one.
Was the biology Exam always one of the first? I wish it was later so I would have more time to study for it.
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Don't know, didn't do it. I think they should have stuck with english on a friday though.
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okay, so do ligase enzymes anneal the complementary base pairs, or the DNA backbone?
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backbone...
bps can pair by themselves v h bonds
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backbone...
bps can pair by themselves v h bonds
yeah I thought so, thanks :)
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do recombinant plasmids need to be placed with a donor cell, in order for successful insertion into a target cell,
or can they be inserted without being placed within a donor cell?
thanks.
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Also, is a liposome a micelle?
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No: Liposomes are made out of a phospholipid bilayer, and a micelle is made out of a phospholipid layer - so a liposome can carry aqueous substances while a micelle can only carry lipid-soluble substances
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do recombinant plasmids need to be placed with a donor cell, in order for successful insertion into a target cell,
or can they be inserted without being placed within a donor cell?
thanks.
Either. Relying on a donor cell takes longer/has a lower success rate, which is why we usually use other processes.
Electroporation is the standard, just zap stuff with electricity so that it's induced to take up plasmids
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here we go again;
how could one accurately define polymorphism?
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also; do most fossils that are above a certain age, require mineralisation, in order to be preserved as a fossil?
(this might be a slightly confusing question)
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additionally; what is the difference between a selection pressure, and a selective agent?
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here we go again;
how could one accurately define polymorphism?
Polymorphism occurs when there are two or more alleles present in a population, where the rarest allele is at a frequency higher than can be explained by mutation alone.
It's critical that you have the second bit about mutation, multiple alleles alone means nothing.
additionally; what is the difference between a selection pressure, and a selective agent?
At a guess, pressure is something macroscopic (say the environment) whilst a selective agent is a much more specific factor (say an antibiotic on a culture dish)
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yep, thank you..
I think you are actually right about your guess too.
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also; do most fossils that are above a certain age, require mineralisation, in order to be preserved as a fossil?
(this might be a slightly confusing question)
I'm relatively sure all fossils in sedimentary rock result in mineralization, only exceptions would be like tree sap or ice fossils which we barely have mentioned.
for instance a bone would decompose after less than 100 years so the only way it can really be preserved over thousands and thousands of years is by being replaced by minerals and forming a rock-based fossil.
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okay, this was in the 2010 insight.
Question 8
A woman with type B blood has two children, one with type A blood and one with type O blood. Her partner has type O blood. What can be concluded from this information?
A. Neither the woman nor the man could be the biological parent of the child with type A blood.
B. The man could not be the biological father of either child.
C. The man could be the biological father of the child with type O blood, but not the child with type A blood.
D. The man must be the biological father of the child with type O blood and could be the biological father of the child with type A blood.
what do you believe the answer is?
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okay, this was in the 2010 insight.
Question 8
A woman with type B blood has two children, one with type A blood and one with type O blood. Her partner has type O blood. What can be concluded from this information?
A. Neither the woman nor the man could be the biological parent of the child with type A blood.
B. The man could not be the biological father of either child.
C. The man could be the biological father of the child with type O blood, but not the child with type A blood.
D. The man must be the biological father of the child with type O blood and could be the biological father of the child with type A blood.
what do you believe the answer is?
C.
What's the right answer?
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yes, C was marked correct, but I don't understand why A can't also be correct.
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okay hang on, this child could be IA and i right?
so the man could be the father. my bad.
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In regards to this question from insight 2010
In the wild, the likelihood of producing a white, crossed-eyed Bengal tiger is 1 in every 10,000, an approximation based on documented observations of white cubs in their natural habitat. There are very few adult white tigers in the wild. When bred in captivity, mortality rates of cubs are in excess of 80%. The recessive allele that produces white, cross eyed tigers is also linked with other, often fatal characteristics including immune deficiency, scoliosis (curvature) of the spine, cleft palates and early death.
1d. i. What is the name of the event that has produced the recessive allele in the Bengal tiger?
1 mark
Solution
Deleterious mutation.
^what is a deleterious mutation... I just wrote gene mutation.
is this just a deletion mutation? and how could that be inferred?
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In regards to this question from insight 2010
In the wild, the likelihood of producing a white, crossed-eyed Bengal tiger is 1 in every 10,000, an approximation based on documented observations of white cubs in their natural habitat. There are very few adult white tigers in the wild. When bred in captivity, mortality rates of cubs are in excess of 80%. The recessive allele that produces white, cross eyed tigers is also linked with other, often fatal characteristics including immune deficiency, scoliosis (curvature) of the spine, cleft palates and early death.
1d. i. What is the name of the event that has produced the recessive allele in the Bengal tiger?
1 mark
Solution
Deleterious mutation.
^what is a deleterious mutation... I just wrote gene mutation.
is this just a deletion mutation? and how could that be inferred?
del·e·te·ri·ous/ˌdeliˈti(ə)rēəs/
Adjective: Causing harm or damage
It's just a word describing that the mutation is fatal. Nothing to do with deletion :) If I had done that question I would have just wrote mutation, but I wouldn't know if the "deleterious" is necessary for getting a mark. Probably ask a teacher.
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Deleterious mutations aren't necessary fatal, they just reduce the relative fitness of the organism. Most are probably just early stop codons (nonsense mutations).
An example might be SCA in humans (not nonsense though) which is deleterious but not fatal. As you've probably been told over and over again, it actually protects you from malaria.
Requiring "deleterious mutation" is a pretty harsh marking scheme, personally I would have written just "mutation"
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Mutation should be good enough.
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Hi :)
Can anyone tell me what we need to know about apoptosis?
Thanks in advance!
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In general:
Know a VCAA approved definition of what it is and why it occurs. Can it occur without external stimuli etc. Be able to give a rough sequence of events. Be able to differentiate between apoptosis and necrosis.
If you want extra credit, know the p53 gene :P
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Yeah, p53 gene and tumor suppressing gene are involved. Cell shrinks, nucleus breaks down, organelles recycled, dead cell fragments engulfed by phagocytes. :)
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What is the difference between a hypervariable region and a short tandem repeat?
Also, with gene therapy, the effects are sometimes short lived - is this because the cells usually die before it has a chance to undergo cell division to produce another cell with the gene?
Thanks.
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mmm fine distinction, i had to go find my biology dictionary.
i get the feeling than an HVR is much more variable than an STR. so whilst we have a library of STR sequences that we can match individuals to, an HVR could conceivably be different across the entire population
For gene therapy, that's one of the reasons but the crux is just that the procedure is still being refined empirically. In other words, nobody reaaally knows what they're doing and every time they make a mistake they change something to fix it. So until we have solutions to problems like immune response/stability/vectors etc. it's very hard to get a long term response
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I see, so if there was a question on the exam that stated for example:
What is the difference between a short tandem repeat and a hypervariable region, and or:
Why are the effects of gene therapy sometimes short lived?
What is the best way to answer these questions?
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im just posting so it goes into the " show new replies" lol
i wanna know the answer to your questions
they are good ones.
lol sorry i cant help.. got no clue
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Wikipedia defines it as:
Short tandem repeat:
A short tandem repeat (STR) in DNA occurs when a pattern of two or more nucleotides are repeated and the repeated sequences are directly adjacent to each other. The pattern can range in length from 2 to 50 base pairs (bp) (for example (CATG)n in a genomic region) and is typically in the non-coding intron region. A short tandem repeat polymorphism (STRP) occurs when homologous STR loci differ in the number of repeats between individuals. By identifying repeats of a specific sequence at specific locations in the genome, it is possible to create a genetic profile of an individual.
Hypervariable region:
A hypervariable region (HVR) is a location within nuclear DNA or the D-loop of mitochondrial DNA in which base pairs of nucleotides repeat (in the case of nuclear DNA) or have substitutions (in the case of mitochondrial DNA). Changes or repeats in the hypervariable region are highly polymorphic.
Here we are comparing: 'A short tandem repeat (STR) in DNA occurs when a pattern of two or more nucleotides are repeated...' with '...in which base pairs of nucleotides repeat (in the case of nuclear DNA) or have substitutions (in the case of mitochondrial DNA)...'
Can you distinguish the differences between this information provided?
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Nature of Biology Third Edition Book 2 defines it as:
Short tandem repeats (STRs): Chromosomal sites where many copies of short DNA sequence are joined end to end; also termed microsatellites. Sequences are normally 2 to 4 base pairs, and the number of repeats are very variable between unrelated people.
Hypervariable regions (HVRs): Regions on chromosomal DNA in which great variation exists in unrelated individuals, often as a result of variation in the number of repeats in short base sequences.
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Nature of Biology Third Edition Book 2 states:
Hypervariable regions of DNA that are currently used for identification are:
Short tandem repeats in nuclear DNA...
Hypervariable regions in mtDNA...
Would that mean that short tandem repeats are hypervariable regions? But if that was the case, then why categorize it in this way?
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I see, so if there was a question on the exam that stated for example:
Why are the effects of gene therapy sometimes short lived?
Check however many marks it is, then list the appropriate amount of reasons in a paragraph: cell death before replication, immune response, low efficacy delivery etc.
On the HVR/STR thing, it seems to be a very subtle difference. From what I understand, the HVR is referring to the literal location on the chromosome where there is variation. An STR, however, describes the specific mutation/insertion that has been observed.
So it would seem that an STR could be at an HVR location.
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Thanks Russ.
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1. Are germ line cells diploid?
2.
It would be expected that the mass of the cell would increase measurably during
A. S phase.
B. G1 phase.
C. G2 phase.
D. M and C phases.
Answer: A.
Is DNA that heavy?
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Question 2
The chromosomes in a human somatic cell can be arranged to form a karyotype. In a normal
human male the chromosomes in a karyotype will be arranged into
A. 46 pairs of chromosomes, which include one large X chromosome and a smaller Y
chromosome.
B. 44 pairs of chromosomes, which include one large X chromosome and a smaller Y
chromosome.
C. 23 pairs of homologous chromosomes, including one large X chromosome and a
smaller Y chromosome.
D. 22 pairs of homologous chromosomes and one large X chromosome and a smaller
Y chromosome.
Apparently the answer is D.
Aren't the X and Y chromosome homologous to one another? I heard somewhere these two are homologous that's why meiosis cannot occur if you are missing a homologous chromosome such as a Y chromosome (in a male).
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The answer is C. Whoever wrote the exam should be punched in the head. You are right.
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To answer the other questions yes germline cells are diploid and I'll leave the other question to Russ but I'm thinking that it could be correct - if you've ever isolated DNA in a prac there's a shitload of it. But, having said that, I think it is a silly question and that there is also a likelihood that one of the G phases results in a large increase in mass because of the considerable growth that occurs in the cytoplasm either general activities or in preparation for mitosis.
Also, I have a question of my own: what's the difference between centrioles and centrosomes? They seem to have very similar functions. Relating to this, would any discussion about centrioles/centrosomes best be left out when answering a question on nuclear division so as not to discriminate against plants?
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q2.
Isn't D? I remember my teacher said X and Y aren't homolgous so if its for a male then theres 22 pairs (autosomal) and 2 of the sex chromsomes (X and Y) and if it's a female then you can say there are 23 homologous pairs due to thier sex chromsomes both XX. I think....
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q2.
Isn't D? I remember my teacher said X and Y aren't homolgous so if its for a male then theres 22 pairs (autosomal) and 2 of the sex chromsomes (X and Y) and if it's a female then you can say there are 23 homologous pairs due to thier sex chromsomes both XX. I think....
I thought that too originally.
Source: http://www.wisegeek.com/what-are-homologous-chromosomes.htm
For example, human somatic cells have 46 chromosomes within their nuclei, or 23 pairs of homologous chromosomes. One of each pair of the homologous chromosomes comes from the mother and one from the father. The human gamete cells, sperm and ova (eggs), each contain only 23 chromosomes. During fertilization, one sperm and one ovum fuse creating a cell that has the full complement of 46 chromosomes.
I remember Andrew Douch saying the two were homologous though.
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Just because they are not autosomal it doesn't mean that they are not homologous. Your teacher is plain wrong. (Sorry but this really frustrates me).
http://en.wikipedia.org/wiki/Homologous_chromosome
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexChromosomes.html
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It would be expected that the mass of the cell would increase measurably during
A. S phase.
B. G1 phase.
C. G2 phase.
D. M and C phases.
Answer: A.
i think the answer is right, he way that i interpretted it was when it said 'measurably' i thought of DNA replication because it does hapen quickly and the mass does increase a lot - i think :)
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Q. Why are the effects of gene therapy for CF so temporary?
A. Effects of gene therapy are temporary because the normal CFTR gene is not incorporated into the DNA of chromosomes.
Are we expected to know this? I would have said that it is due to the cells normally dying before the replication can take place in large enough amounts.
These questions are from Insight 2007 Exam 2 (Biology).
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To answer the other questions yes germline cells are diploid and I'll leave the other question to Russ but I'm thinking that it could be correct - if you've ever isolated DNA in a prac there's a shitload of it. But, having said that, I think it is a silly question and that there is also a likelihood that one of the G phases results in a large increase in mass because of the considerable growth that occurs in the cytoplasm either general activities or in preparation for mitosis.
Also, I have a question of my own: what's the difference between centrioles and centrosomes? They seem to have very similar functions. Relating to this, would any discussion about centrioles/centrosomes best be left out when answering a question on nuclear division so as not to discriminate against plants?
An associated pair of centrioles, arranged perpendicularly and surrounded by an amorphous mass of dense material (the pericentriolar material) constitutes the compound structure known as the centrosome.[1]
Centrioles are a very important part of centrosomes, which are involved in organizing microtubules in the cytoplasm.[8][9] The position of the centriole determines the position of the nucleus and plays a crucial role in the spatial arrangement of the cell.
(Wikipedia)
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Insight exams are a load of crap (if you can't tell I'm in a feisty mood). If the information about the exact type of gene therapy is not given to you then you shouldn't have to know this. Some vectors incorporate DNA into the chromosomes, others insert it into the cell as free DNA so it is not replicated during mitosis.
I'm not sure if we need to know this. Nature of Biology covers this in unit three (and refers you onto this in its unit four discussion of gene therapy). Either adenoviruses or retroviruses can be used as vectors in humans. I think knowing the basics is suffice but it's hard to know really.
Thanks for the info on centrosomes/centrioles :)
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Question 22
Mitochondrial DNA (mtDNA) can be used to trace the evolutionary history of a species. A
characteristic of mtDNA not used to distinguish it from nuclear DNA is
A. lack of recombination.
B. descent through the maternal line.
C. high copy number.
D. molecular structure.
Can anyone explain?
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Question 17
Mitochondrial DNA is used to establish the relatedness between organisms in evolutionary biology, because
it
A. Is only inherited in males.
B. Has more genes than nuclear DNA.
C. Mutates more slowly than nuclear DNA.
D. Is only inherited in females
I'm pretty sure it mutates more rapidly than nuclear DNA.
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Question 17
Mitochondrial DNA is used to establish the relatedness between organisms in evolutionary biology, because
it
A. Is only inherited in males.
B. Has more genes than nuclear DNA.
C. Mutates more slowly than nuclear DNA.
D. Is only inherited in females
I'm pretty sure it mutates more rapidly than nuclear DNA.
yeah i always thought it did/
is D the answer?
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Q. Why are the effects of gene therapy for CF so temporary?
A. Effects of gene therapy are temporary because the normal CFTR gene is not incorporated into the DNA of chromosomes.
Are we expected to know this? I would have said that it is due to the cells normally dying before the replication can take place in large enough amounts.
These questions are from Insight 2007 Exam 2 (Biology).
Yeah, I would definitely say you should know about retroviruses/adenoviruses as well as other methods of gene therapy such as use of liposomes, bacteria, such as the agrobacterium in plants, and ballistics and microinjection. Plus the benefits/risks of each.
A major one is chromosome incorporation, which is obviously beneficial, as the gene would be permanently part of the genome, and any cells derived from this cell would contain the corrected gene.
Also, probably not a bad idea to have an idea of stem cell, and nuclear transfer and embryo splitting.
Anyone else learn about DNA chips? I reckon it is a pretty cool technique.
Anyhow, for this question, poorly worded, or just me? From VCAA 2001.
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Molecular structure is the same except for its circularity - it is DNA after all.
mt.DNA mutates more slowly except for the D-loop.
-
Q. Why are the effects of gene therapy for CF so temporary?
A. Effects of gene therapy are temporary because the normal CFTR gene is not incorporated into the DNA of chromosomes.
Are we expected to know this? I would have said that it is due to the cells normally dying before the replication can take place in large enough amounts.
These questions are from Insight 2007 Exam 2 (Biology).
Yeah, I would definitely say you should know about retroviruses/adenoviruses as well as other methods of gene therapy such as use of liposomes, bacteria, such as the agrobacterium in plants, and ballistics and microinjection. Plus the benefits/risks of each.
A major one is chromosome incorporation, which is obviously beneficial, as the gene would be permanently part of the genome, and any cells derived from this cell would contain the corrected gene.
Also, probably not a bad idea to have an idea of stem cell, and nuclear transfer and embryo splitting.
Anyone else learn about DNA chips? I reckon it is a pretty cool technique.
Anyhow, for this question, poorly worded, or just me? From VCAA 2001.
Is it B?
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Question 22
Mitochondrial DNA (mtDNA) can be used to trace the evolutionary history of a species. A
characteristic of mtDNA not used to distinguish it from nuclear DNA is
A. lack of recombination.
B. descent through the maternal line.
C. high copy number.
D. molecular structure.
Can anyone explain?
The question said NOT. Differences betweeen mtDNA and nuclearDNA include mtDNA's lack of recombination, passage down only through the maternal line, high copy number, meaning that there are more mitochondria in a cell than nuclei, and hence more mtDNA than nuclear DNA. One thing that is the same between the two is that they both have identical structure, hence option D is correct.
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Q. Why are the effects of gene therapy for CF so temporary?
A. Effects of gene therapy are temporary because the normal CFTR gene is not incorporated into the DNA of chromosomes.
Are we expected to know this? I would have said that it is due to the cells normally dying before the replication can take place in large enough amounts.
These questions are from Insight 2007 Exam 2 (Biology).
Yeah, I would definitely say you should know about retroviruses/adenoviruses as well as other methods of gene therapy such as use of liposomes, bacteria, such as the agrobacterium in plants, and ballistics and microinjection. Plus the benefits/risks of each.
A major one is chromosome incorporation, which is obviously beneficial, as the gene would be permanently part of the genome, and any cells derived from this cell would contain the corrected gene.
Also, probably not a bad idea to have an idea of stem cell, and nuclear transfer and embryo splitting.
Anyone else learn about DNA chips? I reckon it is a pretty cool technique.
Anyhow, for this question, poorly worded, or just me? From VCAA 2001.
Is it B?
Yeah. The way I read the question, it implies that both of the plants are heterozygous though...
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Question 7
a. A widely accepted theory of evolution states than species will gradually change over time.
Name this theory and state 3 key elements involved with the theory
Question 7
a. Natural selection (1 mark);
Any two of:
- individuals in a population contain differing genotypes and therefore differing
phenotypes
- a struggle for survival occurs in populations due to selective pressures
- the best suited phenotypes produce more offspring and therefore each new
generation will contain proportionally more of the favourable phenotype
- overtime, the new variations are so different from the original population that a new
species has evolved
Would gradualism be correct?
By the way, would anyone be in favour of creating a new post (part 2) of this one?
Or perhaps we should stay in this one?
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Could someone please explain to me how the gametes of the mother arose? Why can't there be a possibility for a gamete to have a translocated chromosome and a green one as well? They have one with a translocated chromosome and a red one :S
I'm just so confused :(
EDIT: I'm mostly confused about the "possible gametes"- surely you could have another combination? :S
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Could someone please explain to me how the gametes of the mother arose? Why can't there be a possibility for a gamete to have a translocated chromosome and a green one as well? They have one with a translocated chromosome and a red one :S
I'm just so confused :(
EDIT: I'm mostly confused about the "possible gametes"- surely you could have another combination? :S
You generally have one of each chromosome going into the gametes. Remember the translocated chromosome still can have chromosome 21 beside it because it is part of chromosome 21.
But with a translocated chromosome and a chromosome 14, you are counting 2 chromosome 14s.
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Golden yeah the answer is screwed, it's clearly leading you into gradualism. Both gradualism and punctuated equilibrium are theories explaining natural selection.
Akira - there can't be a green/red and a green because they are now part of a homologous pair and will segregate.
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Question 7
a. A widely accepted theory of evolution states than species will gradually change over time.
Name this theory and state 3 key elements involved with the theory
Question 7
a. Natural selection (1 mark);
Any two of:
- individuals in a population contain differing genotypes and therefore differing
phenotypes
- a struggle for survival occurs in populations due to selective pressures
- the best suited phenotypes produce more offspring and therefore each new
generation will contain proportionally more of the favourable phenotype
- overtime, the new variations are so different from the original population that a new
species has evolved
Would gradualism be correct?
By the way, would anyone be in favour of creating a new post (part 2) of this one?
Or perhaps we should stay in this one?
I reckon they are right. Gradualism/punctuated equilibrium are types of evolution. The process is still the same. i.e. population variation, lots of offspring and hence a struggle for survival and inheritable characteristics.
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4c. What are two techniques that might be used to develop transgenic organisms?
Solution
Any two of the following:
1. Micro-injection of DNA of the gene into the host cell (somatic or egg cell)
2. Transfer using a virus (adenovirus or retrovirus)
3. Ballistics (gene gun)
4. Electric pulse
Was 1,3,4 even part of the course?
Thanks to all that have answered my questions. I really appreciate it.
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4c. What are two techniques that might be used to develop transgenic organisms?
Solution
Any two of the following:
1. Micro-injection of DNA of the gene into the host cell (somatic or egg cell)
2. Transfer using a virus (adenovirus or retrovirus)
3. Ballistics (gene gun)
4. Electric pulse
Was 1,3,4 even part of the course?
Thanks to all that have answered my questions. I really appreciate it.
Yes. If you have a Biozone book, I highly recommend reading it.
Microinjection is literally injecting a gene into the nucleus with a tiny needle.
Retroviruses infect a cell and then incorporate their DNA into chromosomes (like the herpes virus) Adenoviruses do not.
Ballistics uses a gene gun which shoots small gold/tungsten particles coated with the gene of interest into cell nuclei.
Electric pulse is the 'heat shock' method used to make bacteria more competent to take up a recombinant plasmid.
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Question 7
a. A widely accepted theory of evolution states than species will gradually change over time.
Name this theory and state 3 key elements involved with the theory
Question 7
a. Natural selection (1 mark);
Any two of:
- individuals in a population contain differing genotypes and therefore differing
phenotypes
- a struggle for survival occurs in populations due to selective pressures
- the best suited phenotypes produce more offspring and therefore each new
generation will contain proportionally more of the favourable phenotype
- overtime, the new variations are so different from the original population that a new
species has evolved
Would gradualism be correct?
By the way, would anyone be in favour of creating a new post (part 2) of this one?
Or perhaps we should stay in this one?
I reckon they are right. Gradualism/punctuated equilibrium are types of evolution. The process is still the same. i.e. population variation, lots of offspring and hence a struggle for survival and inheritable characteristics.
But but but... They are saying that the process is gradual. There is enough debate for neither gradualism nor punk ekk to be entrenched as the adopted theory. Therefore, the answer should be specific to the "type" of natural selection. If you answer natural selection you are implying that all selection is slow.
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Aren't the X and Y chromosome homologous to one another? I heard somewhere these two are homologous that's why meiosis cannot occur if you are missing a homologous chromosome such as a Y chromosome (in a male).
It's a crap question, you can make a case for C or D. I treat them as homologous but it really depends on which textbook you get your definition from. Wikipedia intimates that they're not, fwiw.
is D the answer?
Can't be, both genders inherit mtDNA. The wording is easy to misinterpret though.
Yeah. The way I read the question, it implies that both of the plants are heterozygous though...
They're being sneaky, it specifies a test cross so one is homozygous recessive.
Akira - there can't be a green/red and a green because they are now part of a homologous pair and will segregate.
Essentially yes. Translocation gametes are a pain to do in your head...have you been taught the "cross" method for them? You could probably also comment that even though there are 4 possible gametes that could form, only 2 are viable.
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Question 7
a. A widely accepted theory of evolution states than species will gradually change over time.
Name this theory and state 3 key elements involved with the theory
Question 7
a. Natural selection (1 mark);
Any two of:
- individuals in a population contain differing genotypes and therefore differing
phenotypes
- a struggle for survival occurs in populations due to selective pressures
- the best suited phenotypes produce more offspring and therefore each new
generation will contain proportionally more of the favourable phenotype
- overtime, the new variations are so different from the original population that a new
species has evolved
Would gradualism be correct?
By the way, would anyone be in favour of creating a new post (part 2) of this one?
Or perhaps we should stay in this one?
I reckon they are right. Gradualism/punctuated equilibrium are types of evolution. The process is still the same. i.e. population variation, lots of offspring and hence a struggle for survival and inheritable characteristics.
But but but... They are saying that the process is gradual. There is enough debate for neither gradualism nor punk ekk to be entrenched as the adopted theory. Therefore, the answer should be specific to the "type" of natural selection. If you answer natural selection you are implying that all selection is slow.
True. You'd be hard pressed to find 3 differences between the two though. Essentially they are the same thing, just the rate at which the process occurs is disputed.
I think they meant to keep it simple, but too much reading into the question with this...
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Yeah :) It's all in the interpretation of the question, not the theory itself that we are disagreeing :) At least VCAA exams are okay (generally). Speaking of which, the assessment report came out...
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Yeah :) It's all in the interpretation of the question, not the theory itself that we are disagreeing :) At least VCAA exams are okay (generally). Speaking of which, the assessment report came out...
They are such dogs. They stuff up on a question, and don't even have the guts to own up to it or explain their reasoning!
I feel like emailing the chief examiner and politely asking them for their reasoning... that is all I want.
Do you think this translocation gametes stuff is going to come up? I have no idea how to work them out. :S
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Oh I agree! I am so pissed off about them not explaining!
Translocation of gametes - it shouldn't come up in a confusing form. Shouldn't...
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I would be extremely surprised if they asked you about the mechanics of a cross/gametes involving translocation. Far more likely (if there's a question on it) you'll be asked about how it can occur, consequences, associated diseases, etc.
Or potentially what you would expect if someone with a translocation had a child with a normal person
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I am drawing out how the translocation gametes by hand. Think I am onto something. If I work it out, I shall post. :)
Just for peace of minds sake. :P
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I think Russ knows this...
Only the chromosome 14's will pair because they have more genes on them so it is more important that they are conserved right?
Because if I pair the chromosome 21's then I get gametes which don't come up in that chart thing...
Edit: Here it says there will be six types of gametes. Which one is it?
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I would be extremely surprised if they asked you about the mechanics of a cross/gametes involving translocation. Far more likely (if there's a question on it) you'll be asked about how it can occur, consequences, associated diseases, etc.
Or potentially what you would expect if someone with a translocation had a child with a normal person
i think it would be a question like how gametes are effected by translocation at either meiotic division....
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I would be extremely surprised if they asked you about the mechanics of a cross/gametes involving translocation. Far more likely (if there's a question on it) you'll be asked about how it can occur, consequences, associated diseases, etc.
Or potentially what you would expect if someone with a translocation had a child with a normal person
i think it would be a question like how gametes are effected by translocation at either meiotic division....
The only thing which makes it hard is not knowing how the chomosomes are going to pair...
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Here are 2 photos that might clear that up, they're from my notes last semester. You might want to download them, viewing them in your browser probably won't be easy.
If you don't mind, I'll answer the question properly tomorrow, head is killing me from futsal earlier
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Yeah :) It's all in the interpretation of the question, not the theory itself that we are disagreeing :) At least VCAA exams are okay (generally). Speaking of which, the assessment report came out...
They are such dogs. They stuff up on a question, and don't even have the guts to own up to it or explain their reasoning!
I feel like emailing the chief examiner and politely asking them for their reasoning... that is all I want.
Do you think this translocation gametes stuff is going to come up? I have no idea how to work them out. :S
Hmm well I came across a translocation question in Checkpoints (2009) and it gave the chromosomes in 2 gametes, and asked for what the other 2 gametes would consist of. But what I asked before was if those 4 gametes shown in that diagram were the ONLY possible gametes that would form from the mother...
And sorry if you actually did answer it and I just quickly scanned past it due to my fatigue zZZzz.
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I seriously hope translocation involving gametes does not show up on the biol exam, because it confuses the hell out of me.
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I'm a bit confused about the difference between incomplete dominance and co-dominance as I've heard many different opinions on the matter.
For example:
If you were to breed a white flower with a red flower and the offspring were all pink would VCAA call this incomplete dominance or co-dominance? My teacher at school says its incomplete as its a blend of the two, but I've also heard that it would be co-dominance because in effect both alleles are fully expressed because there are both red and white pigments they are just such small 'dots' they appear to be pink.
What are your thoughts?
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Co-dominance; incomplete dominance is not in the study design, so if VCAA asks a question and you are unsure about whether it is incomplete dominance or co-dominance (the ones where you have to split hairs), just put in co-dominance.
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Co-dominance; incomplete dominance is not in the study design, so if VCAA asks a question and you are unsure about whether it is incomplete dominance or co-dominance (the ones where you have to split hairs), just put in co-dominance.
haha, I can tell you have been listening to douchy.
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Co-dominance; incomplete dominance is not in the study design, so if VCAA asks a question and you are unsure about whether it is incomplete dominance or co-dominance (the ones where you have to split hairs), just put in co-dominance.
haha, I can tell you have been listening to douchy.
He has
AND OMG DOUCHY MENTIONED MY NAME ( MATEEN) AND MY QUESTION ( ABOUT EVOLUTION) IN HIS LAST PODCAST
EVERYONE GO READ IT
IM SO PUMPED
lol :)
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LOL Douchy also mentioned my name - although he couldn't pronounce it properly :P
it came out as "thoosun"
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really??? ah I kinda regret not asking him direct questions...
haha, maybe next year I will send some questions to make up for it.
or not.
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I remember douchy talking about you thusan, but wat was your question matt?
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About the foramen magnum what would be a response about the position of the foramen magnum or how it has changed in hominins to allow bipedalism that is by VCAA standards?
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the foramen magnum gradually became more centrally positioned at the base of the skull as a result of bipedalism (and greater balance), as opposed to quadripedal animals who have a foramen magnum positioned at the back of the skull
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the foramen magnum became more centrally positioned at the base of the skull as a result of bipedalism (and greater balance), as opposed to quadripedal animals who have a foramen magnum positioned at the back of the skull
Sounds good. Thanks.
50th post.
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If you were to breed a white flower with a red flower and the offspring were all pink would VCAA call this incomplete dominance or co-dominance? My teacher at school says its incomplete as its a blend of the two, but I've also heard that it would be co-dominance because in effect both alleles are fully expressed because there are both red and white pigments they are just such small 'dots' they appear to be pink.
What are your thoughts?
This is overthinking it way too much. Neither of the phenotypes observed in the parents are in the child, instead there's an intermediate phenotype. If you wanted to work out whether it was actually just "really small" sections of the different pigments, you'd need to do a biochemical investigation to check cell samples etc.
So until otherwise, incomplete.
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I remember douchy talking about you thusan, but wat was your question matt?
I asked him
If we evolved from the monkeys lol.
And we are still here .. and they are still here.
why the hell arnt the "things in the middle" .. such as H.erectus and aferensis etc .. still here too?
how is it possible that they just "dissapeared "
lol
listen to the podcast
he answers it well
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We need more biology teachers like Douchy!
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We need more biology teachers like Douchy!
Agreed
my teacher is so bad .. I think id learn more if he actually wasnt there.
He gives you the WRONG information and isnt even certified to teach bio lols
our teacher left half way thru sem 1 and now were stuck with this guy.
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I remember douchy talking about you thusan, but wat was your question matt?
I asked him
If we evolved from the monkeys lol.
And we are still here .. and they are still here.
why the hell arnt the "things in the middle" .. such as H.erectus and aferensis etc .. still here too?
how is it possible that they just "dissapeared "
lol
listen to the podcast
he answers it well
I remember that question!!! hahahaha good question too.
We need more biology teachers like Douchy!
Agreed
my teacher is so bad .. I think id learn more if he actually wasnt there.
He gives you the WRONG information and isnt even certified to teach bio lols
our teacher left half way thru sem 1 and now were stuck with this guy.
and yeah I actually think I have might have a greater understanding of year 12 biology, than my biol teacher.
It sucks, because I think I would probably be much more knowledgable and motivated with a better teacher.
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I remember douchy talking about you thusan, but wat was your question matt?
I asked him
If we evolved from the monkeys lol.
And we are still here .. and they are still here.
why the hell arnt the "things in the middle" .. such as H.erectus and aferensis etc .. still here too?
how is it possible that they just "dissapeared "
lol
listen to the podcast
he answers it well
I remember that question!!! hahahaha good question too.
We need more biology teachers like Douchy!
Agreed
my teacher is so bad .. I think id learn more if he actually wasnt there.
He gives you the WRONG information and isnt even certified to teach bio lols
our teacher left half way thru sem 1 and now were stuck with this guy.
and yeah I actually think I have might have a greater understanding of year 12 biology, than my biol teacher.
It sucks, because I think I would probably be much more knowledgable and motivated with a better teacher.
Yeah agreed
I think I easily ( with the VERY limited bio I have) .. know more than my teacher ...
eaaasilly . he marked out prac exams and gave me 9 marks less than i should have received.
He did the same prac exam in his spare time and got 62% ... LOL???? .. I think a teacher shouldnt really get under 95% in any subject they teach.
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I remember douchy talking about you thusan, but wat was your question matt?
I asked him
If we evolved from the monkeys lol.
And we are still here .. and they are still here.
why the hell arnt the "things in the middle" .. such as H.erectus and aferensis etc .. still here too?
how is it possible that they just "dissapeared "
lol
listen to the podcast
he answers it well
I remember that question!!! hahahaha good question too.
We need more biology teachers like Douchy!
Agreed
my teacher is so bad .. I think id learn more if he actually wasnt there.
He gives you the WRONG information and isnt even certified to teach bio lols
our teacher left half way thru sem 1 and now were stuck with this guy.
and yeah I actually think I have might have a greater understanding of year 12 biology, than my biol teacher.
It sucks, because I think I would probably be much more knowledgable and motivated with a better teacher.
Yeah agreed
I think I easily ( with the VERY limited bio I have) .. know more than my teacher ...
eaaasilly . he marked out prac exams and gave me 9 marks less than i should have received.
He did the same prac exam in his spare time and got 62% ... LOL???? .. I think a teacher shouldnt really get under 95% in any subject they teach.
I don't like to be harsh, but that's just pathetic.
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The day teachers are forced to sit exams alongside students will be the day we might get a decent secondary education system.
Teachers would go stupid and strike. Shows how pathetic they are, and how they are afraid they might get exposed.
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its true, they expect us to be able to recite all this knowledge, yet they themselves are incapable. the amount of times i went to the front of class to explain a concept my teacher couldn't....
not that he didn't know, but he couldn't paraphrase and explain it in such a manner that was comprehendable to people who were struggling to grasp the ideologies of the concept.
(sorry for long words, but the exam is coming up and feel as though practise makes perfect :))
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exactly. if they are teaching the content, they should have no problem doing the exam. i would feel bad for the 10% of good teachers who wouldn't really deserve it because they do their job properly, but I doubt it would be an issue for them, because they would know their stuff and have nothing to worry about.
so many teachers would get found out...
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exactly. if they are teaching the content, they should have no problem doing the exam. i would feel bad for the 10% of good teachers who wouldn't really deserve it because they do their job properly, but I doubt it would be an issue for them, because they would know their stuff and have nothing to worry about.
so many teachers would get found out...
hahaha, they would be exposed as witches and burnt at the stake!
but then there would not be enough teachers left..
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I think the problem here isn't really with the teachers, more to do with the fact that teaching has a bad reputation, a low pay:effort ratio and a lot of hidden requirements.
It certainly does attract some brilliant professionals but they invariably get paid off by private schools, so the government is forced to offer incentives to uni graduates to do a DipEd and start teaching (that six week intensive course that made headlines earlier this year).
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What is meant by the diploid chromosome number?
I got this wrong on VCAA 2004 :(
Also, what exactly is an index fossil, and what features does it need to possess?
Thanks.
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What is meant by the diploid chromosome number?
I got this wrong on VCAA 2004 :(
Also, what exactly is an index fossil, and what features does it need to possess?
Thanks.
yea the wording cost me a mark too. diplod number refers to the nuber of chromosomes, so normally 46, but in my question i had nondisjunction occuring (so 47) so be aware of those tricks they might pull.
index fossil/transitional fossil/indicator fossil is sort of the standard upon which unknown fossils are compared. by having that index fossil at a known age of eg. 45 mya, and then a newly discovered, same fossil found at a different location can be presumed to have the same age.
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hey guys, been getting my head back around the confusion of sister chromatids and chromosomes etc and came up with a question,
when a chromosome is single stranded this is equal to one molecule of dna,
when the chromosome is double stranded (so contains two sister chromatids) is this still one molecule of dna, or two?
thanks in advance :)
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hey guys, been getting my head back around the confusion of sister chromatids and chromosomes etc and came up with a question,
when a chromosome is single stranded this is equal to one molecule of dna,
when the chromosome is double stranded (so contains two sister chromatids) is this still one molecule of dna, or two?
thanks in advance :)
Shud be 2 I think.
im no bio expert
But I think .. every chromatid consist of 1 molecule of Dna.
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hey guys, been getting my head back around the confusion of sister chromatids and chromosomes etc and came up with a question,
when a chromosome is single stranded this is equal to one molecule of dna,
when the chromosome is double stranded (so contains two sister chromatids) is this still one molecule of dna, or two?
thanks in advance :)
Shud be 2 I think.
im no bio expert
But I think .. every chromatid consist of 1 molecule of Dna.
yep is two :)
they are both connected at the centromere but remain as separate strands
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thanks!
such a minor thing yet there's still been questions on this... one problem with bio, you need an understanding of every minor detail aha.
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Do restriction enzymes cut through covalent bonds? :S
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It cuts the phosphodiester bond, so yes.
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It cuts the phosphodiester bond, so yes.
so what would be the best answer if they ask what is the name of the bond between the sugar and phospahte?
would it be covalent bond or phosphodiester?
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It cuts the phosphodiester bond, so yes.
Lol I completely forgot unit 3 chemistry :P
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It cuts the phosphodiester bond, so yes.
so what would be the best answer if they ask what is the name of the bond between the sugar and phospahte?
would it be covalent bond or phosphodiester?
Covalent is just a type of bond, if they specifically ask for the name then I would put phospodiester
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It cuts the phosphodiester bond, so yes.
so what would be the best answer if they ask what is the name of the bond between the sugar and phospahte?
would it be covalent bond or phosphodiester?
Covalent is just a type of bond, if they specifically ask for the name then I would put phospodiester
cheers, my teacher mentioned it to us in class, but i didnt realy take notes of it cos in most prac exams the answers are usually covalent bonds.
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Another question, do we need to know about promoters for the unit 4 exam? If so, what are they and what is their role? There's nothing about them in my textbook but I've came across them in a few practise exams...
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I would know what they are, it's not exactly hard: a region of DNA that regulates transcription of another region of DNA. They're typically immediately prior to whatever gene(s) they regulate but they don't have to be (they can be on other chromosomes)
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Does crossing over occur during meiosis: prophase 1 or metaphase 1??? ive gotten those two answers from different teachers...
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Does crossing over occur during meiosis: prophase 1 or metaphase 1??? ive gotten those two answers from different teachers...
Yes I would like to know this as well.... I swear my teachers and textbook say metaphase, but somewhere else I heard/saw it was propase? Sometimes I wish that VCAA wrote the damn textbooks so we would know what to learn for the exams :P
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Prophase 1 - the actual crossing over occurs
Metaphase 1 - the chiasmata are still joined
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Prophase 1 - the actual crossing over occurs
Metaphase 1 - the chiasmata are still joined
Agreed
its actually in the notes book.
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Prophase is pretty pro.
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Prometaphase is even more pro ;)
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Gotta love questions like in VCAA 2006 about why the shrimp are the same species and then the answer is the are not the same species. VCAA are so lame. :P
Anyway, I don't really get how they arrived at the answer for this question. If the male bee produces haploid gametes by mitosis, and the female produces haploid gametes by meiosis, then how do you end up with males? :S
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It's a different sex determination system, males can be produced without fertilization of the oocyte (so they're still haploid)
That's specific knowledge though, you can't infer it from the question.
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And we are supposed to know this?
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Can't hurt, but I doubt it.
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This came from a VCAA exam though, and from the current study design. :(
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Gotta love questions like in VCAA 2006 about why the shrimp are the same species and then the answer is the are not the same species. VCAA are so lame. :P
Actually, I think that VCAA have simply mis-worded their answer on the assessment report. The question was
"Why is the inability to mate sufficient evidence to call the two groups two different species?"
I think that VCAA meant that many students came up with the following response:
'because they cannot mate' --> 0/1
I think VCAA wanted the following answer:
'inability to mate implies inability to produce viable and fertile offspring, which is the criterion for calling two groups different species' --> 1/1
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Gotta love questions like in VCAA 2006 about why the shrimp are the same species and then the answer is the are not the same species. VCAA are so lame. :P
Actually, I think that VCAA have simply mis-worded their answer on the assessment report. The question was
"Why is the inability to mate sufficient evidence to call the two groups two different species?"
I think that VCAA meant that many students came up with the following response:
'because they cannot mate' --> 0/1
I think VCAA wanted the following answer:
'inability to mate implies inability to produce viable and fertile offspring, which is the criterion for calling two groups different species' --> 1/1
You messaged douchy about this didn't you? :P
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Yes! How do you know?
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hey thooozen,
get of VN and do some bio
and lol at your sig, im sure you would not be happy with 46 in boths or bio.
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hey thooozen,
get of VN and do some bio
and lol at your sig, im sure you would not be happy with 46 in boths or bio.
lol. that is how I know. you said he always pronounces your name wrong.
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@ Jdog -> I am!
@ stonecold -> LOL. Always? He only mentioned me once!
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@ Jdog -> I am!
@ stonecold -> LOL. Always? He only mentioned me once!
Serious? I swear I've heard your questions a few times, but I don't really pay much attention, so probably not haha...
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I'm a bit confused about the difference between incomplete dominance and co-dominance as I've heard many different opinions on the matter.
For example:
If you were to breed a white flower with a red flower and the offspring were all pink would VCAA call this incomplete dominance or co-dominance? My teacher at school says its incomplete as its a blend of the two, but I've also heard that it would be co-dominance because in effect both alleles are fully expressed because there are both red and white pigments they are just such small 'dots' they appear to be pink.
What are your thoughts?
Is your name actually ally? because your username is gold if so :P
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no his name is thushan but douch pronounced it thooozen
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lol jdog,
i think he was referring to me
and yeah my name is ally :P
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lol jdog,
i think he was referring to me
and yeah my name is ally :P
haha that is awesome! too clever :p
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hopefully nobody gets freaked out by my very large assortment of questions:
1. How could I describe sticky ends and blunt ends?
2. Does DNA ligase anneal both covalent and hydrogen bonds?
3. Is an Adenovirus simply an alternative name for a Retrovirus?
4. Is a Bacteriophage a virus which infects bacteria?
5. What are some effective/common vectors for the genetic modification of plants?
6. What are the differences between a microsatellite and a STR? and are these sections of DNA mainly used fro DNA fingerprinting and profiling?
7. What is the main purpose of the southern blot technique?
8. Can both Substitution and Frameshift mutations be classified as Point mutations?
9. What exactly is Deamination and how can it cause a mutation?
10. What exactly is a Tautomeric shift and how can it cause a mutation?
11. Is comparative anatomy an evidence of evolutionary relationships?
12. Is Ribosomal RNA single stranded and linear?
13. Could random mating be a source of variation.
14. Can Sex-linked traits be either X-linked or Y-linked?
thank you, and as usual + karma to anybody who helps :)
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1. sticky ends have a complementary overhang of bases allowing them to form hydrogen bonds so can 'stick' to the matching strand. Blunt ends are when both strands are cut at exactly the same point with no overhang so cannot be rejoined, more useful in gel electropherisis where you just want sections to be separate.
2. not a clue in the world...it sure does though. haha
3. I think retrovirus' contain RNA where as adenovirus' contain DNA, do we need to know that?
4. Nay, they're a virus that affect bacteria
5. Bacteria i think is the main one, i remember an exam question on this where they placed bacteria around a plant and the trick was that the infectious strand in the dna had to be removed so that it did not act as a vector
and that's a start for now, need to scoot. :)
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misread question 2, i thought you said HOW does dna ligase anneal the bonds...
i'm relatively sure it re-joins the covalent(phosphodiester) bonds, yet i think the hydrogen bonds occur themselves b/w matching bases. not 100% positive
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1. sticky ends have a complementary overhang of bases allowing them to form hydrogen bonds so can 'stick' to the matching strand. Blunt ends are when both strands are cut at exactly the same point with no overhang so cannot be rejoined, more useful in gel electropherisis where you just want sections to be separate.
2. not a clue in the world...it sure does though. haha
3. I think retrovirus' contain RNA where as adenovirus' contain DNA, do we need to know that?
4. Nay, they're a virus that affect bacteria
5. Bacteria i think is the main one, i remember an exam question on this where they placed bacteria around a plant and the trick was that the infectious strand in the dna had to be removed so that it did not act as a vector
and that's a start for now, need to scoot. :)
haha thank you, and I mistyped plants instead of bacteria for 4. :)
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2. Does DNA ligase anneal both covalent and hydrogen bonds?
It joins the fragments, but the hydrogen bonds are a product of interaction between the 2 strands.
3. Is an Adenovirus simply an alternative name for a Retrovirus?
No. They're two different taxonomical virus families.
6. What are the differences between a microsatellite and a STR? and are these sections of DNA mainly used fro DNA fingerprinting and profiling?
microsatellites can be STRs, yes. and yes, pretty much, i've never heard of any other major uses
7. What is the main purpose of the southern blot technique?
Detection of nucleic acids (ie DNA sequences). There's also western blot etc.
8. Can both Substitution and Frameshift mutations be classified as Point mutations?
Point mutations are where there's only 1 base difference, so frameshift can't cause them.
9. What exactly is Deamination and how can it cause a mutation?
From the name, it's the removal of an amine group. It can occur to any molecule, not just DNA. When it happens in DNA, if not repaired it has altered the base sequence and thus the protein. The thing is, since the bases are similar, deamination can change one base to another...this won't be flagged by the inbuilt repair system of the body.
10. What exactly is a Tautomeric shift and how can it cause a mutation?
This is seriously on the course? Mao can give you a way better answer than me, since it's a chemical term but there are keto and enol forms of molecules and tautomeric shift is between them. When it happens in DNA -> mutation.
12. Is Ribosomal RNA single stranded and linear?
From memory, it's single stranded but it can form loops when complementary sequences match up. Can't remember if all the subunits do the same thing.
13. Could random mating be a source of variation.
It enables genetic variation in a population (why it's part of the HW preconditions) but I wouldn't describe it as a "source" of genetic variation. That's semantics though.
14. Can Sex-linked traits be either X-linked or Y-linked?
Yes, but X linked are way more common/interesting
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10. What exactly is a Tautomeric shift and how can it cause a mutation?
This is seriously on the course? Mao can give you a way better answer than me, since it's a chemical term but there are keto and enol forms of molecules and tautomeric shift is between them. When it happens in DNA -> mutation.
probably not specifically, but it's a good example of a possible cause of mutations.
btw, thanks again.
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Whoa, VCAA 2007 was a stretch!
Some difficult questions in there.
Anyone reckon this would be an acceptable answer for question 9b.
"DNA evidence which indicates a reduction in production of fibrous proteins such as keratin, which could indicate less hair production and would likely coincide with when humans began wearing clothes."
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i don't think so ,
becuase less hair wasn't a direct conseqeunce of cltohes it was becuase body was more exposed to sunlight, I m pretty sure we began losing hair before cltohes.
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i don't think so ,
becuase less hair wasn't a direct conseqeunce of cltohes it was becuase body was more exposed to sunlight, I m pretty sure we began losing hair before cltohes.
fair enough. :)
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Whoa, VCAA 2007 was a stretch!
Some difficult questions in there.
Anyone reckon this would be an acceptable answer for question 9b.
"DNA evidence which indicates a reduction in production of fibrous proteins such as keratin, which could indicate less hair production and would likely coincide with when humans began wearing clothes."
Probably not
I think my answer was relevant though ;)
We began wearing clothes when the female decided to run shit their way
No more needs to be said.
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Whoa, VCAA 2007 was a stretch!
Some difficult questions in there.
Anyone reckon this would be an acceptable answer for question 9b.
"DNA evidence which indicates a reduction in production of fibrous proteins such as keratin, which could indicate less hair production and would likely coincide with when humans began wearing clothes."
Probably not
I think my answer was relevant though ;)
We began wearing clothes when the female decided to run shit their way
No more needs to be said.
llollll! that was good :p
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"6. What are the differences between a microsatellite and a STR? and are these sections of DNA mainly used fro DNA fingerprinting and profiling?"
I know about STR's but I actually haven't heard of microsatellites?
do we need to know them well?
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Where did that question come from?
Wikipedia says theyre the same thing... "Microsatellites, also known as Simple Sequence Repeats (SSRs), or sometimes Short Tandem Repeats (STRs), are repeating sequences of 1-6 base pairs of DNA.[1]"
*shrug*
(I haven't heard of them either)
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it was just sillysmile's question from the last page but yeah, left me lost as i hadn't heard of them at all (haven't seen it in any exams or anything either)
STR's are solely useful for dna profiling, yus?
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Yeah not much else...(Dont code for anything)
There may be a subtle difference thought..."A short tandem repeat (STR) in DNA occurs when a pattern of two or more nucleotides are repeated and the repeated sequences are directly adjacent to each other. The pattern can range in length from 2 to 50 base pairs (bp) (for example (CATG)n in a genomic region) and is typically in the non-coding intron region"... seems longer but besides from that i cant see much, i wouldnt let it keep me up at night anyway
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if ~50 base pairs of length is the only difference i wouldn't imagine there'll be any questions concerning it then, short tandem repeats should be enough, thanks man
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VCAA lists this as part of the course:
Application of gene technologies: cloning of organisms; transformation; stem cell differentiation; genetic screening, gene therapy.
How much do we need to know about cloning of organisms? Would we be required to state the steps in cloning techniques?
With gene therapy what would be a VCAA friendly response with regards to the process?
How much do we need to know about stem cell differentiation?
Embryonic stem cells can differentiate into any cell, however the removal will consequently prevent the embryo from further development and 'die'.
Adult stem cells are more specialised.
There are many ethical issues associated with this research.
(Any more?)
Can anyone add to that list of what we have to know - addressing any of these topics would be appreciated - cloning of organisms; transformation; stem cell differentiation; genetic screening, gene therapy.
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for cloning http://vcenotes.com/forum/index.php/topic,30868.0.html
i must admit in class we didn't go over this dotpoint of the course in huge detail, lots of people i've heard didn't even know it was a part of the course.
therefore this, backed up with the fact that exams i've seen usually ask questions about these whereas the whole thing is explained in the question seems to indicate a pretty general knowledge is enough.
Gene Therapy would be the insertion of a functioning gene into an organism so as to allow normal function/ production of necessary proteins.
a neap question on this got me because it has to be remembered that the non-functioning gene isn't "replaced", it would still be present yet a new functioning gene also present.
Also that you can discuss the affects that these have on allele distributions in human population
And maybe one or two pre-prepared ethical issues ( haven't thought of these myself yet)
I've seen questions on this point in neap exams but i haven't noticed it much in vcaa. Bit odd.
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well i gave my detailed explanation on cloning in the thread, i think u were there lol, so id rather not repeat.
stem cells come in 3 forms
totipotent- can differentiate into any cells (taken from 2-8 cell embryos)
pluripotant- can differentiate into most cells (taken from inner lining of embryos)
multipotent- can only differentiate into a specific cell (taken from adult bone marrow cells, adult stem cells)
genetic screening involves the analysis of one's DNA in order to determine if genetic disorders exist. this is usually associated with the interruption of speciation in humanity, so you can go on to say that through treatments those that would usually be deemed 'unfit' due to genetic disadvantages are able to survive well enough to yield children, thus giving rise to more people able to carry that disadvantaged allele, and so increasing the allele frequency of a condition that would otherwise decrease by natural selection.
gene therapy involves the therapeutic process by which genes that are lacked by someone with an untreatable, inherited condition are cultured and implated into the specific cells as treatment. disadvantages include the safety of the process and how not all cells can have genes introduced to them (eg. brain cells). cells ideal for gene therapy include adult bon marrow cells as they are in constant supply, and divide motitically to yield more cells with the introduced gene. viruses and liposomes are usually used as vectors for gene therapy, as the viruses will find a host and transmit its DNA (and the desired gene) into the cell.
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well i gave my detailed explanation on cloning in the thread, i think u were there lol, so id rather not repeat.
stem cells come in 3 forms
totipotent- can differentiate into any cells (taken from 2-8 cell embryos)
pluripotant- can differentiate into most cells (taken from inner lining of embryos)
multipotent- can only differentiate into a specific cell (taken from adult bone marrow cells, adult stem cells)
you forgot omnipotent: Having unlimited authority or power and can differentiate into every single cell at the same time(taken from the awesomeness cells of a deity/god ).
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well i gave my detailed explanation on cloning in the thread, i think u were there lol, so id rather not repeat.
stem cells come in 3 forms
totipotent- can differentiate into any cells (taken from 2-8 cell embryos)
pluripotant- can differentiate into most cells (taken from inner lining of embryos)
multipotent- can only differentiate into a specific cell (taken from adult bone marrow cells, adult stem cells)
you forgot omnipotent: Having unlimited authority or power and can differentiate into every single cell at the same time(taken from the awesomeness cells of a deity/god ).
lmao somebody's been reading 1984......
oh btw people, can someone link me to the thread with the vcaa 09 exam? i just did it and need to vent.
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I think after the length of time this bio study design has been going for (since 2006) they realise what most common text books and teachers would teach and what they would not teach. Unless they wanted to be real assholes they wouldn't put something in there like cloning or nuclear transfer(hopefully..)
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I think that's just the sort of thing they would do.
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I think after the length of time this bio study design has been going for (since 2006) they realise what most common text books and teachers would teach and what they would not teach. Unless they wanted to be real assholes they wouldn't put something in there like cloning or nuclear transfer(hopefully..)
Nuclear transfer is rather simple, and has been in past exam(s).
If they wan't to be assholes, there will be a question saying:
a) What is DNA sequencing?
b) Outline the process by which a DNA sequence is obtained
Our teacher said we don't have to know it so I haven't bothered to learn it.
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I never learnt anything about it ... damn
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i'm looking at the statistical grade assesment on vcaa for bio last year,
anyone get why it's out of 150?
if there are 90 marks...how...does this total to...150?
o.O
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i'm looking at the statistical grade assesment on vcaa for bio last year,
anyone get why it's out of 150?
if there are 90 marks...how...does this total to...150?
o.O
there are 90 marks for psychology, in regards to biology there are 75.
since the biology exams are marked separately by different teachers this becomes 150.
75 times 2 =150.
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aaaha. ah i'm a fool. thanks :)
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this also means 77% was an a+ last year...
i like that.
a lot.
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this also means 77% was an a+ last year...
i like that.
a lot.
that's sexy news.
btw did you do the umat this year?
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yay i got 88%
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i was thinking a+ would be 90% so was a bit eh. so this is damn attractive, aha. :)
and didn't do the umat actually. for undergraduate med i don't have the funds or interest to travel outside melbourne and monash as the only current undergrad degree is just too competitive.
also i'm not 100% positive medicine is for me, i have a huge interest in a lot of sciences and other things so i'd rather start out undergraduate and living the high life, then go after post-grad if i decide it's definitely for me.
oops, lifestory.
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i was thinking a+ would be 90% so was a bit eh. so this is damn attractive, aha. :)
and didn't do the umat actually. for undergraduate med i don't have the funds or interest to travel outside melbourne and monash as the only current undergrad degree is just too competitive.
also i'm not 100% positive medicine is for me, i have a huge interest in a lot of sciences and other things so i'd rather start out undergraduate and living the high life, then go after post-grad if i decide it's definitely for me.
oops, lifestory.
I like the thinking, and I think you will figure out what you really want to be.
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VCAA 09 sucked, especially the multi choice question about operons.
Main evolution question was stupid too.
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Can someone explain Q7 from VCAA 2009.
I don't get where all these normal alleles come from, and won't the daughters DNA just be whatever colour that was used to stain it?
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What do you mean "all these normal alleles"? If you're referring to the 4 used to plate onto the microarray, they've been artificially synthesised and supplied to whoever is doing the investigation.
The DNA colour is determined by its fluorescence. So if it anneals with the dna already in the plate, it will remain and thus show a colour. The idea is that they've put all 4 possible mutations of that base onto the microarray. Then they've added the "normal" DNA and the daughter's DNA to each field. If it matches, it binds and thus is not washed away and will fluoresce.
So the daughter's DNA will only fluoresce based on what she got from her parents - if normal, green and if mutated, red. You're not actually "staining" the DNA.
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What do you mean "all these normal alleles"? If you're referring to the 4 used to plate onto the microarray, they've been artificially synthesised and supplied to whoever is doing the investigation.
The DNA colour is determined by its fluorescence. So if it anneals with the dna already in the plate, it will remain and thus show a colour. The idea is that they've put all 4 possible mutations of that base onto the microarray. Then they've added the "normal" DNA and the daughter's DNA to each field. If it matches, it binds and thus is not washed away and will fluoresce.
So the daughter's DNA will only fluoresce based on what she got from her parents - if normal, green and if mutated, red. You're not actually "staining" the DNA.
So the probes won't fluoresce if DNA doesn't bind to them?
Isn't that what they have said though? Normal DNA is labelled green, and cancer person DNA is labelled red?
I am used to the other way around, where you label the DNA, and then it can hybridise with the probes, and then only labelled DNA will remain.
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So the probes won't fluoresce if DNA doesn't bind to them?
Nope, because then they're washed away and aren't retained in the well, so there's nothing there that's been tagged.
They're labelling the probe because if they labelled the DNA then every well would produce a colour when inspected. This way if it doesn't bind, there'll be no colour.
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What I don't get is these 'normal' alleles that have been fluoresced to appear green right?
I'm guessing they've been made in the lab?
They will hybridise with the normal DNA chips.
Why can't the red ones do that?
The cancer persons DNA has been fluoresced red. What if they have the normal allele?
They don't have to have a mutant allele, as mentioned in the stem. 'Only 60%'
I don't get what the colours are for either. VCAA's explanation has me confused...
And sorry, in the question it says the solutions with the DNA are labelled.
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Ah okay, 60%. I skimmed it and just assumed it was saying p53 is always there, since it's such a major factor.
Okay, the cancer person's DNA will fluoresce red always (because it's been labelled red). If they have the mutant allele, you will see the red in one of the other wells (ie NOT the normal allele well). If they don't have a p53 mutation, you will see the red in the far left well...although it'd be mixed with green to make...some other colour.
So the red tagged DNA can bind any of them, depends on whether the cancer patient has the mutation or not. In the question, however, since the red fluorescence is in the 3rd well, the patient has the mutation.
The question does suck though, i doubt they'll make this mistake again.
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i didnt really find a problem in this question, lost a mark by stating the probe as a RNA strand instead of DNA, damn u primers!
what is it that you guys dont understand? (sorry but i really cbf reading through previous posts)
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okay, so what do you think the answer to the following question (from stav 2007) is?
Turner's Syndrome is an example of chromosomal aneuploidy, i.e. a variation in chromosome number. In the case of Turner's Syndrome the individual has only one X chromosome
Q12
A person with the turner genotype would phenotypically be:
A. male as males have one X chromosome
B. female as there is no Y chromosome
C. unisexual being phenotypically uncertain regarding gender
D. normal female as only one X chromosome is ever activated in a cell
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i'd say c as the others are somewhat referring to genotype where as the question says phenotypically.
though i could be wrong, don't know x&y chromosomes in that much detail so i guess one of the others could be correct.
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i'd say c as the others are somewhat referring to genotype where as the question says phenotypically.
though i could be wrong, don't know x&y chromosomes in that much detail so i guess one of the others could be correct.
I thought C too, but apparently the answer is B
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Ah okay, 60%. I skimmed it and just assumed it was saying p53 is always there, since it's such a major factor.
Okay, the cancer person's DNA will fluoresce red always (because it's been labelled red). If they have the mutant allele, you will see the red in one of the other wells (ie NOT the normal allele well). If they don't have a p53 mutation, you will see the red in the far left well...although it'd be mixed with green to make...some other colour.
So the red tagged DNA can bind any of them, depends on whether the cancer patient has the mutation or not. In the question, however, since the red fluorescence is in the 3rd well, the patient has the mutation.
The question does suck though, i doubt they'll make this mistake again.
Thanks Russ. This is what I thought. Wouldn't that make their answer to the last question wrong as well, because I said the daughters alleles would appear whatever colour they stained them?
My understanding of DNA probes/microarray chips was that every allele in the wells is a probe and is known. Labelled DNA from the source, is then added to the DNA chip, and if the person has an present allele on the chip, it will hybridize, and become stuck to that particular probe. Then, the chip is rinsed, and all DNA which has not hybridized get washed away. Then, whichever probes fluoresce, are known to have come from the source DNA.
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i'd say c as the others are somewhat referring to genotype where as the question says phenotypically.
though i could be wrong, don't know x&y chromosomes in that much detail so i guess one of the others could be correct.
I thought C too, but apparently the answer is B
Yeah, it is B.
My teacher told me this.
Y chromosome = male
No Y chromosome = female
So XXY is male and XXX is female etc.
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i'd say c as the others are somewhat referring to genotype where as the question says phenotypically.
though i could be wrong, don't know x&y chromosomes in that much detail so i guess one of the others could be correct.
I thought C too, but apparently the answer is B
Yeah, it is B.
My teacher told me this.
Y chromosome = male
No Y chromosome = female
So XXY is male and XXX is female etc.
I dont get how the answer is B.
If you only have 1 x chromosome for turner .. how can it be in a female? .. xxx = 3 x chromosomes??
what obvious thing am i missing here?
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i'd say c as the others are somewhat referring to genotype where as the question says phenotypically.
though i could be wrong, don't know x&y chromosomes in that much detail so i guess one of the others could be correct.
I thought C too, but apparently the answer is B
Yeah, it is B.
My teacher told me this.
Y chromosome = male
No Y chromosome = female
So XXY is male and XXX is female etc.
I dont get how the answer is B.
If you only have 1 x chromosome for turner .. how can it be in a female? .. xxx = 3 x chromosomes??
what obvious thing am i missing here?
What I just said. :P
SRY gene, which makes someone male, is on the Y chromosome. No Y chsm, no SRY gene, no male. Simple really.
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Because the Y chromosome pretty much only encodes genes for making you "male".
If you don't have it, you will be phenotypically female.
Wouldn't that make their answer to the last question wrong as well, because I said the daughters alleles would appear whatever colour they stained them?
Yeah that's what I thought as well. I suspect that they've made a mistake, because I cannot see how you can reconcile the two pieces of information. They probably wrote the questions first (to assess XYZ dot points of the study design) and then provided appropriate background information. Unfortunately, in the background information was the fact about the 60% penetrance and it all got confused. I think what you would expect to see if the girl has the mutation is a green well and a red well and 2 black wells. If she doesn't, you'd see 3 black wells and a brown? well. I suppose if you used the appropriate technique you could observe the individual light emissions, but yeah...don't like that question.
that, or i've gotten horribly confused somewhere
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i'd say c as the others are somewhat referring to genotype where as the question says phenotypically.
though i could be wrong, don't know x&y chromosomes in that much detail so i guess one of the others could be correct.
I thought C too, but apparently the answer is B
Yeah, it is B.
My teacher told me this.
Y chromosome = male
No Y chromosome = female
So XXY is male and XXX is female etc.
I dont get how the answer is B.
If you only have 1 x chromosome for turner .. how can it be in a female? .. xxx = 3 x chromosomes??
what obvious thing am i missing here?
What I just said. :P
SRY gene, which makes someone male, is on the Y chromosome. No Y chsm, no SRY gene, no male. Simple really.
that is simple, thanks :)
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Because the Y chromosome pretty much only encodes genes for making you "male".
If you don't have it, you will be phenotypically female.
Wouldn't that make their answer to the last question wrong as well, because I said the daughters alleles would appear whatever colour they stained them?
Yeah that's what I thought as well. I suspect that they've made a mistake, because I cannot see how you can reconcile the two pieces of information. They probably wrote the questions first (to assess XYZ dot points of the study design) and then provided appropriate background information. Unfortunately, in the background information was the fact about the 60% penetrance and it all got confused. I think what you would expect to see if the girl has the mutation is a green well and a red well and 2 black wells. If she doesn't, you'd see 3 black wells and a brown? well. I suppose if you used the appropriate technique you could observe the individual light emissions, but yeah...don't like that question.
that, or i've gotten horribly confused somewhere
This exactly what I was thinking when I did the Q Russ. I was like, there was going to be both colours, but I just new that wouldn't be the answer.
Just hope that stupid ambiguous stuff like this doesn't come up on Friday. It will wreck everything...
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Stupid question. Completely stupid.
The daughter's result would have been red regardless, because that was the colour her DNA would have been stained with. The question should have been worded like this:
Would the results of the daughter be identical to those of the mother as depicted above?
VCAA stuffs up questions, and we students pay for it.
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Stupid question. Completely stupid.
The daughter's result would have been red regardless, because that was the colour her DNA would have been stained with. The question should have been worded like this:
Would the results of the daughter be identical to those of the mother as depicted above?
VCAA stuffs up questions, and we students pay for it.
wait, the way i interpreted the question was there are two probes introduced to the DNA sample. one which will illuminate green and another red. should someone possess the mutant allele, the will-be-red probe will bind to the complimentary sequence and thus when the sample is karyotyped it will illuminate red, indicating the base sequence for the mutation exists. if it is the normal allele, the opposite will occur but with the will-be-green probe.
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That's right, but if the daughter inherited the normal allele, her DNA would be stained red anyway; so the result would actually be yellow, as the 'red' and 'green' DNA hybridise at the same field.
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That's right, but if the daughter inherited the normal allele, her DNA would be stained red anyway; so the result would actually be yellow, as the 'red' and 'green' DNA hybridise at the same field.
i think your understanding this from a chemistry ph point of view. try and visualise it as a electrophoresis graph, with separate lines, a line will be green and the other red. i think i get where your coming from though, in that as they are the same fragment lengths they will travel the same distance and so illuminate in the same position giving the hybrid colour. im sure if your explained your point legitimately you'd get the mark for this one....i hope anyway....
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It is the DNA which is stained, not the probes. The probes are fixed in the little holes in the micro array chip.
And it has nothing to do with electrophoresis.
The cultural/technological evolution question plain sucked as well.
And I still don't get the operon question from MC. Why can't there be genes on a plasmid with an operon?
We did an experiment with plasmids and green fluorescent protein this year, and to get the the bacteria to glow, we had to supply arabanose sugar to activate the operon so that the gene would be expressed,
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That's right, but if the daughter inherited the normal allele, her DNA would be stained red anyway; so the result would actually be yellow, as the 'red' and 'green' DNA hybridise at the same field.
Where they fucked up with this question was with
a) The staining of and hybridization with normal alleles. Why? What is the point?
b) The use of two dyes. Again irrelevant. The point of the dye is so that you can see which ones have hybridised to the probes. Or to identify different DNA samples if you are using more than one.
This in my opinion was one of the shittest exams VCAA has ever put out.
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Heh, I remember everyone bitching about this question last year. Yeh, it's messed up. Just depends on whatever colour they labelled it. Hurrah for VCAA. I've also just realised that this is my first post in a 19 page Biology thread. How the hell have I not posted in this sooner.
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It is the DNA which is stained, not the probes. The probes are fixed in the little holes in the micro array chip.
And it has nothing to do with electrophoresis.
The cultural/technological evolution question plain sucked as well.
And I still don't get the operon question from MC. Why can't there be genes on a plasmid with an operon?
We did an experiment with plasmids and green fluorescent protein this year, and to get the the bacteria to glow, we had to supply arabanose sugar to activate the operon so that the gene would be expressed,
wasn't there? well i must not remember the exam well..
well for the operon question this is how interpreted it.
it cannot be a) eukaryotic stem cells have all genes switched on, because they are undifferentiated.
cannot be b) the environment has no impact on whether a gene is switched on or off, because a phenotype is influenced by genotype and the environment, so a chemical is produced as required by the body, eg. sweating to reduce heat, the gene which correlates to the protein which allows for pores to open blah blah u get the idea.
canot be d) mutations in distinct regularoy genes will have no effect on related structural genes in eukaryotic cells, because the sole purpose of the regulatory gene is to control structual genes regardless of locus.
it must therefore be c) all bacterial operons are located on a large circular chromosome within a cell, because prokaryotes only consist of a single circular DNA strand. plasmids do not carry the basic genes of the bacterium, but rather additional information transported through the tubey thingies lol.
sorry im not of much help, i just it as the bacterium genome is embodied in the single circular chromosome, not plasmids who i regard as vectors for variation
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That's right, but if the daughter inherited the normal allele, her DNA would be stained red anyway; so the result would actually be yellow, as the 'red' and 'green' DNA hybridise at the same field.
Also, that makes the answer to the prior question wrong, for the purpose of the dyes. Because the red dye doesn't HAVE to be for mutant alleles.
I am feeling slightly better about this exam now, considering that question was completely dud.
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It is the DNA which is stained, not the probes. The probes are fixed in the little holes in the micro array chip.
And it has nothing to do with electrophoresis.
The cultural/technological evolution question plain sucked as well.
And I still don't get the operon question from MC. Why can't there be genes on a plasmid with an operon?
We did an experiment with plasmids and green fluorescent protein this year, and to get the the bacteria to glow, we had to supply arabanose sugar to activate the operon so that the gene would be expressed,
wasn't there? well i must not remember the exam well..
well for the operon question this is how interpreted it.
it cannot be a) eukaryotic stem cells have all genes switched on, because they are undifferentiated.
cannot be b) the environment has no impact on whether a gene is switched on or off, because a phenotype is influenced by genotype and the environment, so a chemical is produced as required by the body, eg. sweating to reduce heat, the gene which correlates to the protein which allows for pores to open blah blah u get the idea.
canot be d) mutations in distinct regularoy genes will have no effect on related structural genes in eukaryotic cells, because the sole purpose of the regulatory gene is to control structual genes regardless of locus.
it must therefore be c) all bacterial operons are located on a large circular chromosome within a cell, because prokaryotes only consist of a single circular DNA strand. plasmids do not carry the basic genes of the bacterium, but rather additional information transported through the tubey thingies lol.
sorry im not of much help, i just it as the bacterium genome is embodied in the single circular chromosome, not plasmids who i regard as vectors for variation
I'm happy to be proven wrong, but that question is also complete bull shit. All the anwers are wrong.
See my post above on the experiment we did in class. The solutions in VCAA says that this does not involve pasmids. Well, a) that is a lie, because from what I understand it does, and b) they don't even mention that is doesn't involve plasmids in the question.
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That's right, but if the daughter inherited the normal allele, her DNA would be stained red anyway; so the result would actually be yellow, as the 'red' and 'green' DNA hybridise at the same field.
Where they fucked up with this question was with
a) The staining of and hybridization with normal alleles. Why? What is the point?
b) The use of two dyes. Again irrelevant. The point of the dye is so that you can see which ones have hybridised to the probes. Or to identify different DNA samples if you are using more than one.
This in my opinion was one of the shittest exams VCAA has ever put out.
a) i think the point was to test students understanding of hybridisation, but in terms of the experiment yea pretty pointless.
b) i think they use two dyes to sort of indicate that the gene is actually present, instead of using one dye and risking that section of DNA going missing of something :S
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Also, that makes the answer to the prior question wrong, for the purpose of the dyes. Because the red dye doesn't HAVE to be for mutant alleles.
I am feeling slightly better about this exam now, considering that question was completely dud.
Yeah, my answer was:
"The purpose of the red dye was to indicate the DNA sequence of the breast cancer allele and show that the breast cancer allele occurred due to the base substitution from the normal allele - G to A"
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It is the DNA which is stained, not the probes. The probes are fixed in the little holes in the micro array chip.
And it has nothing to do with electrophoresis.
The cultural/technological evolution question plain sucked as well.
And I still don't get the operon question from MC. Why can't there be genes on a plasmid with an operon?
We did an experiment with plasmids and green fluorescent protein this year, and to get the the bacteria to glow, we had to supply arabanose sugar to activate the operon so that the gene would be expressed,
wasn't there? well i must not remember the exam well..
well for the operon question this is how interpreted it.
it cannot be a) eukaryotic stem cells have all genes switched on, because they are undifferentiated.
cannot be b) the environment has no impact on whether a gene is switched on or off, because a phenotype is influenced by genotype and the environment, so a chemical is produced as required by the body, eg. sweating to reduce heat, the gene which correlates to the protein which allows for pores to open blah blah u get the idea.
canot be d) mutations in distinct regularoy genes will have no effect on related structural genes in eukaryotic cells, because the sole purpose of the regulatory gene is to control structual genes regardless of locus.
it must therefore be c) all bacterial operons are located on a large circular chromosome within a cell, because prokaryotes only consist of a single circular DNA strand. plasmids do not carry the basic genes of the bacterium, but rather additional information transported through the tubey thingies lol.
sorry im not of much help, i just it as the bacterium genome is embodied in the single circular chromosome, not plasmids who i regard as vectors for variation
I'm happy to be proven wrong, but that question is also complete bull shit. All the anwers are wrong.
See my post above on the experiment we did in class. The solutions in VCAA says that this does not involve pasmids. Well, a) that is a lie, because from what I understand it does, and b) they don't even mention that is doesn't involve plasmids in the question.
look i get that your frustrated, and i would be too. but fact for me is i only lost 1 mark for that question :D lol sorry not to brag because it looks like my approach to it was way off, but you know, i cant complain.
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Yeah, I didn't like that question either...
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lol. sorry if sounds like i'm taking this out on everyone. but this exam got me so frustrated. and i am seriously counting on bio or else i'm screwed...
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likewise :( english and bio i need 42+
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likewise :( english and bio i need 42+
your lang analysis was good. you should get the 42+ you want. i'm screwed for english. done absolutely nothing. put all my eggs in the englang basket, and that isn't going too well either.
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likewise :( english and bio i need 42+
your lang analysis was good. you should get the 42+ you want. i'm screwed for english. done absolutely nothing. put all my eggs in the englang basket, and that isn't going too well either.
thanks :) but at least you have that increadable 48 from last year as a safety net. my 35 for business is gonna drop to 31, shouldve taken it more seriously for sacs...
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And I still don't get the operon question from MC. Why can't there be genes on a plasmid with an operon?
you can get genes organized in an operon that are found on a plasmid
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likewise :( english and bio i need 42+
your lang analysis was good. you should get the 42+ you want. i'm screwed for english. done absolutely nothing. put all my eggs in the englang basket, and that isn't going too well either.
thanks :) but at least you have that increadable 48 from last year as a safety net. my 35 for business is gonna drop to 31, shouldve taken it more seriously for sacs...
thanks, but still there is a long way to go. at least it will all be over soon. :)
We did this experiment in class it. It was actually cool...
http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20laboratory/bacterial%20transformation/results.htm
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http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20laboratory/bacterial%20transformation/results.htm
coooooooollllll
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Is there any difference between a probe and a marker?
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Is there any difference between a probe and a marker?
Yeah, a probe is a single stranded labelled piece of DNA which will hybridise with an allele if it is present, so it can be identified.
A marker is a gene which is located very closely to a gene of interest. If the marker gene is inherited and expressed (i.e. it might produce a specific protein or something) then the gene of interest which is located close to the marker gene will also have been inherited, unless recombination has occurred between the two, which is less and less likely the closer together the two genes are.
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Okay, so I am a little confused about labelling of probes and DNA. If you label your DNA, then obviously it will hybridise with the probe, and fluoresce.
However how do labelled probes work? If you are looking for a single gene/ segment of DNA, you label your probe, then add it to your DNA sample. How do you get rid of non hibridised probes without also washing away the DNA?
Or in each of the experiments, are one of them constantly fixed to a dish?
This is how I would think of DNA probing:
http://upload.wikimedia.org/wikipedia/en/a/a8/NA_hybrid.svg
How does it exist the other way around, where the probe is labelled and not the DNA?
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They're probably fixed, I can't imagine it being too different to heatfixing for an enzyme assay but with a different technique.
I don't do these, but I'd guess that after adding a labelled probe the specific interaction with the target DNA will prevent it being washed away. This could be for a variety of reasons, depending on what lab technique you were using.
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VCAA 2008 Q2a, http://www.vcaa.vic.edu.au/vcaa/vce/studies/biology/pastexams/2008/2008biol2-w.pdf
Assessor's solution:
The newborn baby is DS 11, 15.
• either allele could have come from the mother
• neither allele could have come from the father
What's it saying? Is the child from the mother or not?
I wrote that it was not from the mother, as at least one of the 'DS' genes must have been inherited from the father (as we assume no mutations)
Don't know what the answer is saying
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Didn't go through the paper, but those are just the two points they want you to make: either of the alleles could come from the mother (doesn't determine anything) but since neither could come from the father it's not his child.
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VCAA 2008 Q2a, http://www.vcaa.vic.edu.au/vcaa/vce/studies/biology/pastexams/2008/2008biol2-w.pdf
Assessor's solution:
The newborn baby is DS 11, 15.
• either allele could have come from the mother
• neither allele could have come from the father
What's it saying? Is the child from the mother or not?
I wrote that it was not from the mother, as at least one of the 'DS' genes must have been inherited from the father (as we assume no mutations)
Don't know what the answer is saying
What you've said is right :)
The baby has not inherited any of the father's alleles so it cannot be his child.
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VCAA 2008 Q2a, http://www.vcaa.vic.edu.au/vcaa/vce/studies/biology/pastexams/2008/2008biol2-w.pdf
Assessor's solution:
The newborn baby is DS 11, 15.
• either allele could have come from the mother
• neither allele could have come from the father
What's it saying? Is the child from the mother or not?
I wrote that it was not from the mother, as at least one of the 'DS' genes must have been inherited from the father (as we assume no mutations)
Don't know what the answer is saying
What you've said is right :)
The baby has not inherited any of the father's alleles so it cannot be his child.
Yeah, it says it a bit further down that some people wrongly tried to argue it was his baby
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1. what is an operon and what is it's purpose?
2. what is a restriction fragment length polymorphism. (wow that's long)
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an operon is only found in prokaryotic organism where it consists of the gene and the promoter region.
do you need to know about polymorphism?
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Operons can have more than one gene.
RFLP: you've got restriction sequences that are cut, but they're in different places in different people (hence the term polymorphism). This means that when you do restriction enzyme analysis, you get different fragment lengths in different people
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What do we need to know about cultural and technological evolution?
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What do we need to know about cultural and technological evolution?
basically understand and know the definitions of them.
questions regarding them will typically be a definition question
OR
you'll get a scenario and need to be able to distinguish what type of evolution it is
ie. when hominins started burial rituals this was an example of what kind of evolution?
(answer is cultural)
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What do we need to know about cultural and technological evolution?
basically understand and know the definitions of them.
questions regarding them will typically be a definition question
OR
you'll get a scenario and need to be able to distinguish what type of evolution it is
ie. when hominins started burial rituals this was an example of what kind of evolution?
(answer is cultural)
that's could be interpreted either way though.. I mean what about cryogenics???
nah I'm only joking :)
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hhhahah true that.
i keep getting questions on this wrong though, it's like "what is the most evolving evolution since hominins"
and i'd say with all the technology we have it'd be that, but it's always cultural...
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hhhahah true that.
i keep getting questions on this wrong though, it's like "what is the most evolving evolution since hominins"
and i'd say with all the technology we have it'd be that, but it's always cultural...
cultural develops technological
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Can someone exaplain the Q 6di on VCAA 2009.
I don't get VCAA's answer at all.
And for 6dii. you couldn't say bipedal locomotion because australopithicus and paranthropos had that as well is that right?
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And also, i found out why they label probes haha.
http://en.wikipedia.org/wiki/Fluorescent_in_situ_hybridization
Learn this people. I have a feeling it will come up in some form, seeing how poorly probes were answered on last years paper.
Also, examiners report said it was made of DNA, but it could also be made of RNA yeah. Why not, it would still hybridize all the same.
Wiki says probes can be DNA or RNA, not that that is the best source though. :P
Also, primers are strictly RNA yeah?
I know you need them for PCR to target the gene of interest
Also, in DNA replication are primers required, and likewise, are they required in transcription, or do the polymerases recognise the promoter regions ?
I remember reading somewhere that on the lagging strand of DNA, small primers are added and elongated by DNA polymerase, and they are later replaced with DNA, and then ligase joins the phosphodiester bonds between okazaki fragments..
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Also, examiners report said it was made of DNA, but it could also be made of RNA yeah. Why not, it would still hybridize all the same.
Wiki says probes can be DNA or RNA, not that that is the best source though. :P
-_- i wrote RNA and corrected it wrong. damn u assessors!
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Also, examiners report said it was made of DNA, but it could also be made of RNA yeah. Why not, it would still hybridize all the same.
Wiki says probes can be DNA or RNA, not that that is the best source though. :P
-_- i wrote RNA and corrected it wrong. damn u assessors!
Nah, it is right. The main bit is that you wrote labelled.
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Also, examiners report said it was made of DNA, but it could also be made of RNA yeah. Why not, it would still hybridize all the same.
Wiki says probes can be DNA or RNA, not that that is the best source though. :P
-_- i wrote RNA and corrected it wrong. damn u assessors!
Nah, it is right. The main bit is that you wrote labelled.
labelled? hold on ill write my response :)
A synthesised piece of RNA,single-stranded,this is used to identify a sequence of DNA by binding to its complimentary fragment and illuminating under UV light.
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Also, examiners report said it was made of DNA, but it could also be made of RNA yeah. Why not, it would still hybridize all the same.
Wiki says probes can be DNA or RNA, not that that is the best source though. :P
-_- i wrote RNA and corrected it wrong. damn u assessors!
Nah, it is right. The main bit is that you wrote labelled.
labelled? hold on ill write my response :)
A synthesised piece of RNA,single-stranded,this is used to identify a sequence of DNA by binding to its complimentary fragment and illuminating under UV light.
I'm not sure. See, a probe doesn't have to be labelled. In the question that followed, they labelled the DNA, and not the probe, whereas in the FISH technique above, the probe is labelled and not neccessarily the DNA, although it probably has some stain to make it visible.
The probe won't fluoresce unless it has some kind of radiactive of fluorescent marker on it though, but as I said, you didn't need the probe to be labelled for that experiment, because the DNA had been labelled.
This was what I wrote:
"A probe is a labelled piece of single stranded DNA or RNA which has a complementary base sequence to a segment of DNA of interest (i.e. a gene), which allows it to be identified by hybridisation."
Probably best to just go with VCAA's definition though...
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lol very true, yours was a good answer though
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could a probe really be RNA?
i mean RNA is only for translation and transcription... i don't think i've heard of it bonding to DNA...
though i suppose they have complementary bases so...maybe. hm
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could a probe really be RNA?
i mean RNA is only for translation and transcription... i don't think i've heard of it bonding to DNA...
though i suppose they have complementary bases so...maybe. hm
For VCAA's purposes, just stick to DNA. Doubt RNA is wrong though...
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Yeh it can be RNA as well NOB Page 424: "This kind of probe is commonly a piece of single-stranded DNA (or RNA)"
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Adaptive Radiation and Divergent Evolution; how would you define the difference between them?
and yeah true thanks, vcaa seem to say DNA so may as well just keep it simple and stick to just DNA probes.
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I read somewhere they were the same thing but not sure
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AWMG brohz
u guys are all technical about this shit
just wing the exam
stop asking questions
ur too smart for me . and im getting jalous!
JUst winG it !
be SIKKKKKK and fkkk the exam upppp
goodlucklkkskdkkk
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Probes can be RNA but DNA is more often used in exams, etc. You pretty much can't go wrong stating DNA probes unless the question has specified that it used RNA probes or the probe contains uracil (etc.).
Adaptive radiation is divergent evolution except it involves different populations (usually many) adapting to a range of environment niches.
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hey, i just did this question from lisachem 2010and need advice for marking. question was "name the method that would be used to determine the definite age for a 100 million year old fossilised fish" to which i responded "uranium-144 dating" but the answer is radioisotopic dating. is this still a correct answer or wrong?
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hey, i just did this question from lisachem 2010and need advice for marking. question was "name the method that would be used to determine the definite age for a 100 million year old fossilised fish" to which i responded "uranium-144 dating" but the answer is radioisotopic dating. is this still a correct answer or wrong?
Isn't the isotope of uranium usually used uranium-235?
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eh either way im wrong lol
but regardless would putting the actual technique instead the type of technique lose me the mark?
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eh either way im wrong lol
but regardless would putting the actual technique instead the type of technique lose me the mark?
'
I would always go with " radiometric/radioisotopic dating"
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hey, i just did this question from lisachem 2010and need advice for marking. question was "name the method that would be used to determine the definite age for a 100 million year old fossilised fish" to which i responded "uranium-144 dating" but the answer is radioisotopic dating. is this still a correct answer or wrong?
The question stated 'name the method' rather than 'name a method' - you might lose a mark depending on the marker.
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hey, i just did this question from lisachem 2010and need advice for marking. question was "name the method that would be used to determine the definite age for a 100 million year old fossilised fish" to which i responded "uranium-144 dating" but the answer is radioisotopic dating. is this still a correct answer or wrong?
The question stated 'name the method' rather than 'name a method' - you might lose a mark depending on the marker.
Better off just saying radioisotopic or radiometric and specify if it asks. ie. if it asked is carbon-14 usable to date this 1bajilion year old fossil? ... obviously not.
Our teacher said that you still get the mark if you specify the isotope BUT if you specify the wrong isotope for the age, you lose the mark. whereas if you just gave the general answer, you can't go wrong.
Probes can be RNA but DNA is more often used in exams, etc. You pretty much can't go wrong stating DNA probes unless the question has specified that it used RNA probes or the probe contains uracil (etc.).
Adaptive radiation is divergent evolution except it involves different populations (usually many) adapting to a range of environment niches.
So is this whereas divergent evolution only involves...two populations?
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Can anyone describe the procedure of microarray technology and genetic screening?
Can't find a website that clearly explains them, and the notes I have just give a general answer, like "to detect the presence/absence of a particular allele", but it doesn't exactly say how it does that.
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watch some youtube clips on microarrays they're okay
http://www.youtube.com/watch?v=VNsThMNjKhM
http://www.youtube.com/watch?v=SNbt--d14P4
http://www.youtube.com/watch?v=ui4BOtwJEXs
virtual lab
http://learn.genetics.utah.edu/content/labs/microarray/
it just shows you the relative level of expression of each gene between two samples... just a quantitative measure
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we need to know microarrays? :/
derp.
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As evidenced by last year, they'll provide the details but I knowing it can't hurt.
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ahh yeah that's fine.
this virtual lab thing's kind of interesting anyways...
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Also, primers are strictly RNA yeah?
I know you need them for PCR to target the gene of interest
Also, in DNA replication are primers required, and likewise, are they required in transcription, or do the polymerases recognise the promoter regions ?
I remember reading somewhere that on the lagging strand of DNA, small primers are added and elongated by DNA polymerase, and they are later replaced with DNA, and then ligase joins the phosphodiester bonds between okazaki fragments..
Anyone please?
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Yes, they're required for DNA replication for DNA pol to build off.
And yes, on the lagging strand you get primers added every so often, as the replication fork extends. The DNA polymerases that replace the primer/synthesize new DNA are actually different but I doubt you need to know that. And yes, ligase joins gaps.
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And also, i found out why they label probes haha.
http://en.wikipedia.org/wiki/Fluorescent_in_situ_hybridization
Learn this people. I have a feeling it will come up in some form, seeing how poorly probes were answered on last years paper.
Also, examiners report said it was made of DNA, but it could also be made of RNA yeah. Why not, it would still hybridize all the same.
Wiki says probes can be DNA or RNA, not that that is the best source though. :P
Also, primers are strictly RNA yeah?
I know you need them for PCR to target the gene of interest
Also, in DNA replication are primers required, and likewise, are they required in transcription, or do the polymerases recognise the promoter regions ?
I remember reading somewhere that on the lagging strand of DNA, small primers are added and elongated by DNA polymerase, and they are later replaced with DNA, and then ligase joins the phosphodiester bonds between okazaki fragments..
in pcr the primers are short dna oligonucleotides
yes in dna replication you need primers
no you don't need primers in transcription since rna pol can synthesize rna without a free hydroxyl group
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Omg I hate the vagueness of the biology study design. So do we actually have to know about operons and their function? RFLP?
And could someone have a look at the image attached-
In stage one shouldn't there be a double up of the X and Y chromosomes so that they are XX and YY? Because if they weren't doubled up how would each cell that originated from the diploid cell be XX and YY?
Also, why are they now "haploid"? I thought the sperm would be haploid.
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watch some youtube clips on microarrays they're okay
http://www.youtube.com/watch?v=VNsThMNjKhM
http://www.youtube.com/watch?v=SNbt--d14P4
http://www.youtube.com/watch?v=ui4BOtwJEXs
virtual lab
http://learn.genetics.utah.edu/content/labs/microarray/
it just shows you the relative level of expression of each gene between two samples... just a quantitative measure
Ahhhk I get how they work now, but then how does hybridisation between the DNA sample and the probes on the array give you an indication on the expression of each gene?
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oh wait
the colour... so if its yellow it means there around half green and half red mrna bound ... so no change in the level of gene expression
if its red then there more mrna from a particular sample in a particular condition (i.e.. strongly expressed in cancer cell)
if its green theres more in the other sample in that condition (i.e. strongly repressed in healthy cell)
but the intensity indicates the magnitude of upregulation or downregulation of gene
read through this scroll to the middle
http://www.ncbi.nlm.nih.gov/About/primer/microarrays.html
http://www.csus.edu/indiv/r/rogersa/Bio181/Microarrays.pdf
do u really have to know all this detail?
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I lost like 2 marks on that q last year.
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I lost like 2 marks on that q last year.
It was a terrible question. Don't get me started...
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Omg I hate the vagueness of the biology study design. So do we actually have to know about operons and their function? RFLP?
And could someone have a look at the image attached-
In stage one shouldn't there be a double up of the X and Y chromosomes so that they are XX and YY? Because if they weren't doubled up how would each cell that originated from the diploid cell be XX and YY?
Also, why are they now "haploid"? I thought the sperm would be haploid.
Notice how it says 22 double stranded autosomes on the second part of the picture, it is haploid then.
At the very top it says 22 double stranded pairs 22*2 = 44 of autosomes
In the second Set of Circles these sex chromosomes are present:X,X,Y,Y
One of these gets distributed to each gamete, and the 22 double stranded pairs are pulled apart at anaphase (i think?) so you get 44 single stranded pairs... and 22 of those go to each gamete (sorry if it was hard to follow...shitty diagram)
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Omg I hate the vagueness of the biology study design. So do we actually have to know about operons and their function? RFLP?
And could someone have a look at the image attached-
In stage one shouldn't there be a double up of the X and Y chromosomes so that they are XX and YY? Because if they weren't doubled up how would each cell that originated from the diploid cell be XX and YY?
Also, why are they now "haploid"? I thought the sperm would be haploid.
Notice how it says 22 double stranded autosomes on the second part of the picture, it is haploid then.
At the very top it says 22 double stranded pairs 22*2 = 44 of autosomes
In the second Set of Circles these sex chromosomes are present:X,X,Y,Y
One of these gets distributed to each gamete, and the 22 double stranded pairs are pulled apart at anaphase (i think?) so you get 44 single stranded pairs... and 22 of those go to each gamete (sorry if it was hard to follow...shitty diagram)
I understand that but where did the extra X and Y chromosomes come from? Shouldn't they have become replicated in stage 1 along with the the replicated autosomes (22 double stranded autosomes)?
Aren't sperm the haploid cells? Not the stage before it? After all, gametes are haploid...
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The cells after the first division are haploid, as homologous chromosomes have separated during he first division. The XX and YY actually means ONE sex chromosome (as per a haploid cell) that has TWO X or Y chromatids. The cells after the second division are also haploid as CHROMATIDS have separated at the centromere in the second division.
Before first division: diploid number of double-stranded chromosomes
After first division: haploid number of double-stranded chromosomes
After second division: haploid number of single-stranded chromosomes
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oh wait
the colour... so if its yellow it means there around half green and half red mrna bound ... so no change in the level of gene expression
if its red then there more mrna from a particular sample in a particular condition (i.e.. strongly expressed in cancer cell)
if its green theres more in the other sample in that condition (i.e. strongly repressed in healthy cell)
but the intensity indicates the magnitude of upregulation or downregulation of gene
read through this scroll to the middle
http://www.ncbi.nlm.nih.gov/About/primer/microarrays.html
http://www.csus.edu/indiv/r/rogersa/Bio181/Microarrays.pdf
do u really have to know all this detail?
What do you mean by 'no change in the level of gene expression'?
If the microarray fluoresces yellow what exactly does that mean?
'YELLOW represents a combination of Control and Sample DNA, where both hybridized equally to the target DNA.' - 'http://www.ncbi.nlm.nih.gov/About/primer/microarrays.html'
How do both the control and sample DNA hybridise equally to the target DNA?
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theres no relative change because both the green (eg. healthy) and red (eg. cancer) cDNA have bound to the reference dna
therefore theres not much more or much less of that gene expressed in that cancer...you got them expressed at equal levels. ie. that gene is active in both cell types
they can hybridize equally because theres lots of dna on the chip... so lets say theres 1 million of the same genes on one chip ... 500k of the red labelled cDNA binds and 500k if the green binds too
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So in a normal case with someone without the cancer, and someone with the cancer, how would the results differ in the microarray as a whole?
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well you don't know until you do it and then you see which gene is upregulated in cancer and then so it shows you that it might be important in cancer development... and then you do further studies to show what this gene does etc..
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Russ if you have a better way of explaining it please do!
but i don't think i would be worrying about it... i dont recall learning anything about microarrays in yr 12...
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Outcomes of cultural evolution in the genus Homo include the following with the exception of:
A. the first use of shaped stone objects as tools.
B. the cultivation of crops.
C. the use of written language.
D. the herding of animals.
Can anyone explain why it is D?
Also, is it acceptable to use DNA triplet and DNA codon interchangeably?
Thanks.
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Russ if you have a better way of explaining it please do!
but i don't think i would be worrying about it... i dont recall learning anything about microarrays in yr 12...
If there's a question about it, there'll be plenty of background information supplied. But the general principle is what's important:
DNA is tagged in two colours and added to a well. If you see colour A, then there's lots of DNA A. If you see colour B, there's lots of DNA B. If you see something in between, then there are both.
From that, you can work out which bits of DNA etc. are relevant to certain cells - so it a tumour has extremely low expression of a gene (ie p53 or Rb) you can conclude it's somehow related
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Russ if you have a better way of explaining it please do!
but i don't think i would be worrying about it... i dont recall learning anything about microarrays in yr 12...
If there's a question about it, there'll be plenty of background information supplied. But the general principle is what's important:
DNA is tagged in two colours and added to a well. If you see colour A, then there's lots of DNA A. If you see colour B, there's lots of DNA B. If you see something in between, then there are both.
From that, you can work out which bits of DNA etc. are relevant to certain cells - so it a tumour has extremely low expression of a gene (ie p53 or Rb) you can conclude it's somehow related
Great answer. Thanks.
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Would we say that after transcription the mRNA leaves the nucleus to go into the cytoplasm or cytosol? Or possibly either can be used?
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Would we say that after transcription the mRNA leaves the nucleus to go into the cytoplasm or cytosol? Or possibly either can be used?
my teacher says to just say cytoplasm
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Cytosol is technically going to be more correct, but cytoplasm is perfectly acceptable (since cytosol is a subset of cytoplasm)
Personally, I'd write cytoplasm
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http://img24.imageshack.us/img24/8376/screenshot20101028at122.png
This is a question from the 2001 VCAA exam that I couldn't understand. I thought the answer would be A but apparently it's B. Can anyone explain to me why?
Thanks :)
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http://img24.imageshack.us/img24/8376/screenshot20101028at122.png
This is a question from the 2001 VCAA exam that I couldn't understand. I thought the answer would be A but apparently it's B. Can anyone explain to me why?
Thanks :)
The question implied that one parent was homozygous recessive through the words 'test cross', and mentioned that one parent was heterozygous at both gene loci.
The genes are also unlinked.
If you do the cross you will find that that B is correct.
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oohh, thanks! i misread it :P
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Gotta love Insights attempt at maths on their 2010 exam MCQ10.
Go learn the binomial distribution ffs...
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Mistake, or just me?
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it looks right..cause the triplet given was the non-coding strand of DNA so the template strand of DNA would be ATT? then mRNA UAA and tRNA AUU :\ sorry if i dont help ><
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I agree, their triplets are back to front, i got 5' UUA 3' for the mRNA
Although I'm notoriously bad at doing genetics in my head :P
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it looks right..cause the triplet given was the non-coding strand of DNA so the template strand of DNA would be ATT? then mRNA UAA and tRNA AUU :\ sorry if i dont help ><
Non-coding strand is the template strand which mRNA is complementary to...
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it looks right..cause the triplet given was the non-coding strand of DNA so the template strand of DNA would be ATT? then mRNA UAA and tRNA AUU :\ sorry if i dont help ><
Non-coding strand is the template strand which mRNA is complementary to...
what?
the template strand is the TEMPLATE strand... not the non coding strand?
im lost lol
what u tryin to say bro?
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template/non coding are synonymous and refer to the same strand of DNA...
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isnt that true only if the strand getting synthesised is DNA not RNA?
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The answers are correct. It is B.
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QUESTION PLEASE
ok
so I know the ratio is 9:3:3:1 when 2 homozygous people have a bang.
HOWEVER
when they linked
sometimes you see weird stuff like 3:1:1:3
why is this?
.
" SOMEONE PLEASE EXPLAIN IN EASY BIOLOGY TERMS .. " :)
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I hate these bloody evolution questions...
How do you do the one below for part d?
Also, what exactly is technological evolution and how is it affected by cultural evolution, which I understand to be 'the passing on of information.'
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The answers are correct. It is B.
I don't think so.
http://en.wikipedia.org/wiki/Coding_strand
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QUESTION PLEASE
ok
so I know the ratio is 9:3:3:1 when 2 homozygous people have a bang.
HOWEVER
when they linked
sometimes you see weird stuff like 3:1:1:3
why is this?
9: 3: 3: 1 applies for heterozygotes. When the genes are linked recombination accounts for the lower amounts, as it is usually that the recombinants in number are less than the non-recombinants.
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The answers are correct. It is B.
I don't think so.
http://en.wikipedia.org/wiki/Coding_strand
The wording was probably incorrect then, but the working was correct.
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QUESTION PLEASE
ok
so I know the ratio is 9:3:3:1 when 2 homozygous people have a bang.
HOWEVER
when they linked
sometimes you see weird stuff like 3:1:1:3
why is this?
9: 3: 3: 1 applies for heterozygotes. When the genes are linked recombination accounts for the lower amounts, as it is usually that the recombinants in number are less than the non-recombinants.
Dont understand man.
ur bio terms are too much.
lol dumb it down to grade 1 bio.
??
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template/non coding are synonymous and refer to the same strand of DNA...
add antisense strand as well
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technology evolution is just basically the evolution and advancement of technology eg genetic engineering.
cultural evolution is new characteristicss that arent transmitted by genes more towards socialising and may or may not be affected by technology as u mentioned its just the passing on of information.
thats what i understand of it anyway
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The answers are correct. It is B.
I don't think so.
http://en.wikipedia.org/wiki/Coding_strand
The wording was probably incorrect then, but the working was correct.
ATT = coding strand
TAA = non-coding strand/template strand
AUU = mRNA
UAA = tRNA
How do you get your answer?
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technology evolution is just basically the evolution and advancement of technology eg genetic engineering.
cultural evolution is new characteristicss that arent transmitted by genes more towards socialising and may or may not be affected by technology as u mentioned its just the passing on of information.
thats what i understand of it anyway
I just don't get their answer to question 6di on the 2009 VCAA exam...
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The answers are correct. It is B.
I don't think so.
http://en.wikipedia.org/wiki/Coding_strand
The wording was probably incorrect then, but the working was correct.
ATT = coding strand
TAA = non-coding strand/template strand
AUU = mRNA
UAA = tRNA
How do you get your answer?
from your own link it says the non coding strrand acts as the template for tRNA and the template strand codes for codons. so in this case the TAA would result in the tRNA being AUU and mRNA beign UAA? :S
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The answers are correct. It is B.
I don't think so.
http://en.wikipedia.org/wiki/Coding_strand
The wording was probably incorrect then, but the working was correct.
ATT = coding strand
TAA = non-coding strand/template strand
AUU = mRNA
UAA = tRNA
How do you get your answer?
from your own link it says the non coding strrand acts as the template for tRNA and the template strand codes for codons. so in this case the TAA would result in the tRNA being AUU and mRNA beign UAA? :S
I think you are misinterpreting. The coding strand will have the SAME sequence as mRNA codons, (accept T's substituted with U's) and the non-coding stand will have the same sequence as tRNA anticodons (accept T's substituted with U's)
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QUESTION PLEASE
ok
so I know the ratio is 9:3:3:1 when 2 homozygous people have a bang.
HOWEVER
when they linked
sometimes you see weird stuff like 3:1:1:3
why is this?
.
" SOMEONE PLEASE EXPLAIN IN EASY BIOLOGY TERMS .. "
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when they are linked, they may have also gone through crossing over which results in recombinants. so new phenotypes will arise as u see the two smaller numbers represent the recombinants
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Two homozygous people "having a bang" is not going to give you a 9:3:3:1 ratio, you'll get only one type of offspring irrespective of linkage/recombination.
Linkage changes the 9:3:3:1 ratio because it allows recombination, which alters the ratio/types of gametes.
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Two homozygous people "having a bang" is not going to give you a 9:3:3:1 ratio, you'll get only one type of offspring irrespective of linkage/recombination.
Linkage changes the 9:3:3:1 ratio because it allows recombination, which alters the ratio/types of gametes.
Can you please explain "recombination"??
DO they HAVE to be LINKED to be crossed over?????????????
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Recombination is the process where paired chromosomes exchange content. So as they line up, you get a "crossover" as per this diagram.
For crossing over/recombination to occur, the two genes must be on the same chromosome but do not necessarily have to be linked.
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Recombination is the process where paired chromosomes exchange content. So as they line up, you get a "crossover" as per this diagram.
For crossing over/recombination to occur, the two genes must be on the same chromosome but do not necessarily have to be linked.
But aren't linked genes on the same chromosome?
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Recombination is the process where paired chromosomes exchange content. So as they line up, you get a "crossover" as per this diagram.
For crossing over/recombination to occur, the two genes must be on the same chromosome but do not necessarily have to be linked.
lol. vce definition of linked genes is genes that are on the same chromosome, do not assort independently and can undergo recombination.
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Recombination is the process where paired chromosomes exchange content. So as they line up, you get a "crossover" as per this diagram.
For crossing over/recombination to occur, the two genes must be on the same chromosome but do not necessarily have to be linked.
lol. vce definition of linked genes is genes that are on the same chromosome, do not assort independently and can undergo recombination.
LOL i thought genes that link
ALL CROSS OVER
wait
does crossing over = recombination?
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going over definitions to make sure i know everything and does anyone know;
Haplogroups
and
Theraputic Cloning
and just having a blonde moment -> what's the name of the non-template strand of DNA?
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going over definitions to make sure i know everything and does anyone know;
Haplogroups
and
Theraputic Cloning
and just having a blonde moment -> what's the name of the non-template strand of DNA?
Ive never heard of halogroups and lol wtf is therapeutic cloning?
-
going over definitions to make sure i know everything and does anyone know;
Haplogroups
and
Theraputic Cloning
and just having a blonde moment -> what's the name of the non-template strand of DNA?
not sure about haplogroups...therapeutic cloning is fertilising eggs purely to make embryonic stem cells i believe.
scratch that. its using a somatic cell and taking its nucleus and inserting it into a donor egg so that the resulting stem cells are the same DNA as the patient so it doesnt cause rejection..a quick summary of it :)
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But aren't linked genes on the same chromosome?
Okay, forget I said anything, for your purposes yes, use stonecold's definition
vce definition of linked genes is genes that are on the same chromosome, do not assort independently and can undergo recombinat
A haplogroup is just a collection of haplotypes, so it's a method of identification (haplotype = certain alleles at certain loci)
what's the name of the non-template strand of DNA?
Has a few, but I call it the coding strand or sense strand
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is haplotypes even on the course?
over 40 exams . i have NOT once seen it.
I have seen therapeutic cloning though .. id be pretty angry if that came up.
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what's the name of the non-template strand of DNA?
Has a few, but I call it the coding strand or sense strand
[/quote]
I mean the...non-coding strand?
non-template=non-coding?
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what's the name of the non-template strand of DNA?
Has a few, but I call it the coding strand or sense strand
I mean the...non-coding strand?
non-template=non-coding?
[/quote]
The template strand is the non-coding strand
-
what's the name of the non-template strand of DNA?
Has a few, but I call it the coding strand or sense strand
I mean the...non-coding strand?
non-template=non-coding?
The template strand is the non-coding strand
[/quote]
Yeah correct.
the way i see it
template strand = non coding strand = the strand that is used for the transcription process.
:) correct?
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lol seriously just stick with one
-
if that's the case, then neither DNA strands are coding strands
i would have thought the template strand is the coding strand, as essentially, it is coding for the mRNA piece -> protein etc.
-
what's the name of the non-template strand of DNA?
Has a few, but I call it the coding strand or sense strand
I mean the...non-coding strand?
non-template=non-coding?
The template strand is the non-coding strand
Yeah correct.
the way i see it
template strand = non coding strand = the strand that is used for the transcription process.
:) correct?
[/quote]
yeah, see what I mean with the question from before now?
-
whyyyyyyyyyyyyyyyy is the non-coding strand the strand that mRNA is...coded...from.
last minute confusion, goddamn. aha
-
if that's the case, then neither DNA strands are coding strands
i would have thought the template strand is the coding strand, as essentially, it is coding for the mRNA piece -> protein etc.
whyyyyyyyyyyyyyyyy is the non-coding strand the strand that mRNA is...coded...from.
last minute confusion, goddamn. aha
i argued my case here
http://ebiology.squarespace.com/douchys-biology-forum/post/1125407#post1125923
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if that's the case, then neither DNA strands are coding strands
i would have thought the template strand is the coding strand, as essentially, it is coding for the mRNA piece -> protein etc.
whyyyyyyyyyyyyyyyy is the non-coding strand the strand that mRNA is...coded...from.
last minute confusion, goddamn. aha
i argued my case here
http://ebiology.squarespace.com/douchys-biology-forum/post/1125407#post1125923
People, just learn this. It is right. Forget what others have told you/what you think.
Last thing you want is to lose easy marks on these types of questions.
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cool cool, so coding strand = has same nucleotide base sequence (U for T) as the mRNA piece transcribed
thanks :D
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"coding strand" is the SAME as the "template strand". The other strand is the "Non-coding strand" or the "complementary strand".
is that right??????????????????????
FKIN HELL
i thought the NON CODING ( TEMPLATE STRAND) WAS USED FOR TRANSCRIPTION?
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As to why there's confusion: everyone wants to be responsible for naming something, so there are multiple interpretations
Just rote learn the right one and never forget it
i thought the NON CODING ( TEMPLATE STRAND) WAS USED FOR TRANSCRIPTION?
This is correct. It's non coding because the literal code of the strand is nonsense
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As to why there's confusion: everyone wants to be responsible for naming something, so there are multiple interpretations
Just rote learn the right one and never forget it
i thought the NON CODING ( TEMPLATE STRAND) WAS USED FOR TRANSCRIPTION?
This is correct.
douchy dosnt seem to think so
but i trust you more anyway
:) thanks
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lol your turning crazy from all the study
-
really?
now I'm confused as well :S
Worst part of genetics
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"coding strand" is the SAME as the "template strand". The other strand is the "Non-coding strand" or the "complementary strand".
is that right??????????????????????
FKIN HELL
i thought the NON CODING ( TEMPLATE STRAND) WAS USED FOR TRANSCRIPTION?
Yeah, you were originally right!
That is why I say the insight Q is wrong...
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"coding strand" is the SAME as the "template strand". The other strand is the "Non-coding strand" or the "complementary strand".
is that right??????????????????????
FKIN HELL
i thought the NON CODING ( TEMPLATE STRAND) WAS USED FOR TRANSCRIPTION?
Yeah, you were originally right!
That is why I say the insight Q is wrong...
so your saying.. that
CODING = template strand
and that is used for transcription?
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coding = nontemplate strand
LOL lets go around in merry go rounds
read the links i put up
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Let me give you a logical explantion which will hopefully clear this up.
What is a template?
It is some kind kind of thing which gives the mould for something else.
Now ask yourself what is transcription?
Where mRNA is synthesised for DNA in the nucleus.
Put the two together, and it is obvious that the template strand acts as the 'template' for mRNA sysnthesis.
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Let me give you a logical explantion which will hopefully clear this up.
What is a template?
It is some kind kind of thing which gives the mould for something else.
Now ask yourself what is transcription?
Where mRNA is synthesised for DNA in the nucleus.
Put the two together, and it is obvious that the template strand acts as the 'template' for mRNA sysnthesis.
IS THE TEMPLATE STRAND CODING OR NON CODING?
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template = non coding
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I concur.
Think of the coding strand as "mirroring" the mRNA codons, that's why it's called the "coding strand".
Eg.
template (non-coding) CCCC
CODING (non-template) GGGG
mRNA GGGG
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I GET IT
THANKS GUYS
lol if this actually comes up in the multiple choice
question 1
The strand which Rna is transcripted from is the
A " NON CODING STRAND"
yummmm :)
omg anything on cloning . i am FARKED
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I concur.
Think of the coding strand as "mirroring" the mRNA codons, that's why it's called the "coding strand".
I do this as well, but mirroring is just going to lead to confusion (for others) because it implies it's the complement :P
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i would stick to one but the same
so like
template/nontemplate
noncoding/coding
antisense/sense
and remember the template strand can be either the top or bottom.... doesn't matter
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i would stick to one but the same
so like
template/nontemplate
noncoding/coding
antisense/sense
and remember the template strand can be either the top or bottom.... doesn't matter
waat do u mean top or bottom?
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"template" and "non template" is relative to the gene you're talking about. since genes can be on either strand, the "template" strand of DNA can differ depending on circumstances
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whoever named the DNA strands was one cruel bastard ahah.
but thanks so much! some stupid confusion like that is the last thing i want to lose an easy mark on... aha
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yep so you can potentially get six open reading frames
but only ONE is correct
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Hahah i just hope to god this wont come up or ill hear all of you guys (inculding me) simultanously cry around the state
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In terms of codominance and incomplete dominance, which are the ALLELES symbols? Is it a letter followed by a super script? eg. IB or would it just be B?
Distinguishing this would be important.
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ONLY USE CODOMINANCE
Or so i've been told... i know ive been using incomplete dominance for ages too..
I'd use the superscript one
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Did you mean I should only use codominance as my answer even if the question involved height and it asked what kind of dominance is height?
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I doubt they will ask what kind of dominance is height seeings as it is polygenic and continuous, without proving you with heaps of info. :S
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I've heard around the forums that incomplete dominance doesnt officially exist inside the confines of the study design, so write co-dominance apparently
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is there anything anybody doesn't quite understand yet?
I'll start:
1. does independent assortment occur in meiosis only?
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I've heard around the forums that incomplete dominance doesnt officially exist inside the confines of the study design, so write co-dominance apparently
this.
it's controversial whether a lot of things previously believed to be incomplete dominance are in fact codominance, so unless it's really clear vcaa wouldn't risk it and will stick to codominance.
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is there anything anybody doesn't quite understand yet?
I'll start:
1. does independent assortment occur in meiosis only?
i believe so yes. as in mitosis they aren't randomly/independently assorted as one half of each chromosome must go into each cell so that they are identical daughter cells.
I think The Law of Segregation still applies. ie. it could be either of the two sister chromatids (received from the mother or father) that go to either cell.
in mitosis
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What exactly does the 3" - 5" thing mean... never really paid much attention to it (great time to ask hey)
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http://www.cic-caracas.org/departments/science/images/08P-210-DNA-5-3.jpg
There's always a phosphate group at the 5' end of the dna, yet on the 3' end there is an available OH group.
To the OH group, new phosphate(with a deoxyribose sugar and whatever base) can be added, whereas the 5' cannot be added to as there's always already a phosphate there.
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what types of gene therapy are permanent? im so confused..i see some things say that it isnt incorporated into the DNA some are..
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if gene therapy involves somatic cells then it won't be passed on to future generations, other than that i think the point of most is that they're relatively permanent...?
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in an insight paper, it says the effects of gene therapy for CF (cystic fibrosis) is only temporary. and the things they mentioned were adenoviruses and liposomes. apparentlythey dont incorporate it into the hosts own chromosomes or something? :\
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I keep forgetting. Does mtDNA mutate faster or slower than nDNA
?
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I keep forgetting. Does mtDNA mutate faster or slower than nDNA
?
FASTER
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faster
every 1000 years a mtDNA mutation occurs, allowing it to be a vital clue into the evolution of species, particularly homo sapians. it supports the out-of-africa theory in that those of african descent show greater mtDNA variation than other races
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can anyone give me a clear precise definion on selection pressure?
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thanks :)
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A selection pressure is an abstract force that shapes organisms as they evolve due to mutation, natural selection, and genetic drift. Examples include predation, climate (drought), competition, etc.
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Selection pressures/agents: the biotic and abiotic factors of the environment that can influence the survival and reproduction of individuals, and ultimately of populations and species.
Stole it from my teachers powerpoint haha.
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I keep forgetting. Does mtDNA mutate faster or slower than nDNA
?
FASTER
only the hypervariable d-loop mutates fast
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Are people sure it mutates faster?
Look at question 7 MC VCAA 2007...
they say more slowly. so i am inclined to stick with that.
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thanks :) yeah i thought mtDNA generally mutates slower...and only faster in the hypervariable d-loop. i didnt wanna seem odd haha :\ the d-loop allows us to tell the time of divergence in relatively recent peridos of time i think
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i actually think it does, but a small region, the hypervariable d-loop, mutates faster (i think) as it is non-coding
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i think the more important thing to know anyway is that mtDNA is not subject to variation other than mutation, as it does not undergo independent assortment and recombination. it is therefore a better measure of evolutionary relationships.
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upto how many years can carbon dating measure? 100,000 years?
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upto how many years can carbon dating measure? 100,000 years?
40
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anything past that we use potassium argon dating right?
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anything past that we use potassium argon dating right?
they seem to like uranium as well.
also, sorry to be picky, but it is 50,000 years for C-14 dating IMO... well at least according to douchy and my teacher :P
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carbon dating is 50,000
potassium-argon 1.3 billion years
uranium-238 4.5 billion years
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upto how many years can carbon dating measure? 100,000 years?
40
50-60 thousand years
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anything past that we use potassium argon dating right?
they seem to like uranium as well.
also, sorry to be picky, but it is 50,000 years for C-14 dating IMO... well at least according to douchy and my teacher :P
and VCAA (more importantly)
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carbon dating is 50,000
potassium-argon 1.3 billion years
uranium-238 4.5 billion years
they are the max periods yeah? not half lifes?
douchy keeps saying the half life pf K-40 is 1.1 billion, but I think he is wrong and means millions yeah?
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carbon dating is 50,000
potassium-argon 1.3 billion years
uranium-238 4.5 billion years
they are the max periods yeah? not half lifes?
douchy keeps saying the half life pf K-40 is 1.1 billion, but I think he is wrong and means millions yeah?
c-14 dating is the only specific date you'll ever need to know...
just need to make sure u know that in k-40 dating, the fossil is not dated, the layers above and below are measured
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carbon dating is 50,000
potassium-argon 1.3 billion years
uranium-238 4.5 billion years
they are the max periods yeah? not half lifes?
douchy keeps saying the half life pf K-40 is 1.1 billion, but I think he is wrong and means millions yeah?
c-14 dating is the only specific date you'll ever need to know...
just need to make sure u know that in k-40 dating, the fossil is not dated, the layers above and below are measured
very good point..i got that wrong in a mc somewhere because i put that it dates the fossil not the layers
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carbon dating is 50,000
potassium-argon 1.3 billion years
uranium-238 4.5 billion years
they are the max periods yeah? not half lifes?
douchy keeps saying the half life pf K-40 is 1.1 billion, but I think he is wrong and means millions yeah?
c-14 dating is the only specific date you'll ever need to know...
just need to make sure u know that in k-40 dating, the fossil is not dated, the layers above and below are measured
haha, yeah, 'ignious rock' according to the 'bad language' podcast
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carbon dating is 50,000
potassium-argon 1.3 billion years
uranium-238 4.5 billion years
they are the max periods yeah? not half lifes?
douchy keeps saying the half life pf K-40 is 1.1 billion, but I think he is wrong and means millions yeah?
c-14 dating is the only specific date you'll ever need to know...
just need to make sure u know that in k-40 dating, the fossil is not dated, the layers above and below are measured
haha, yeah, 'ignious rock' according to the 'bad language' podcast
douchy's got it all covered
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douchy is our man <3
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he was quite literally my main teacher this year, our school faild teacher wise.
he's a genius.
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he was quite literally my main teacher this year, our school faild teacher wise.
he's a genius.
same, the teacher supervisor I have is a dud
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how much info should we put in a question about speciation? (3 marks)
is it OK to put natural selection/genetic drift as a step (just a names)?
-
how much info should we put in a question about speciation? (3 marks)
is it OK to put natural selection/genetic drift as a step (just a names)?
-A population is separated into two (or whatever number) by a geographical barrier, no gene flow can occur.
-The different populations are subjected to different selection pressures arising from their different environments
-The populations undergo natural selection and mutation, and progressively become different (allele frequencies change)
-If the two populations are brought together to interbreed but do not produce viable, fertile offspring, speciation has occurred.
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thanks a lot
-
how much info should we put in a question about speciation? (3 marks)
is it OK to put natural selection/genetic drift as a step (just a names)?
-A population is separated into two (or whatever number) by a geographical barrier, no gene flow can occur.
-The different populations are subjected to different selection pressures arising from their different environments
-The populations undergo natural selection and mutation, and progressively become different (allele frequencies change)
-If the two populations are brought together to interbreed but do not produce viable, fertile offspring, speciation has occurred.
also, specify that there is existing variation within the original population
[edit] also i wouldn't mention genetic drift unless they SPECIFY that it is a particularly small population.
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how much info should we put in a question about speciation? (3 marks)
is it OK to put natural selection/genetic drift as a step (just a names)?
-A population is separated into two (or whatever number) by a geographical barrier, no gene flow can occur.
-The different populations are subjected to different selection pressures arising from their different environments
-The populations undergo natural selection and mutation, and progressively become different (allele frequencies change)
-If the two populations are brought together to interbreed but do not produce viable, fertile offspring, speciation has occurred.
also, specify that there is existing variation within the original population
[edit] also i wouldn't mention genetic drift unless they SPECIFY that it is a particularly small population.
Ah yes I missed that. Remember to mention that genetic variation existed before the populations were separated.
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what's the best example to use when describing the evolution of humans, ie. difference from the old+new world monkey
like for bipedalism, do we talk about the larger heel bone? foramen magnum? etc
thanks :)
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Luck we argued about template strands. It was on there. :P
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Luck we argued about template strands. It was on there. :P
LOL
so lucky man.
I wrote the template strand for the "CODING" strand. and talked about the transcriptional process from there.
Did anyone mention 3-5 end.... i forgot about it . fml
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Luck we argued about template strands. It was on there. :P
LOL
so lucky man.
I wrote the template strand for the "CODING" strand. and talked about the transcriptional process from there.
Did anyone mention 3-5 end.... i forgot about it . fml
I was talking about the multi choice Q...
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so, I would say that this thread was a success :)
awesome contribution from lots of people, good luck with your biology study scores...
it's so satisfying to have completed biology, and for me to never have to study it again....
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it's so satisfying to have completed biology, and for me to never have to study it again....
2011: Psychological science @LaTrobe (bundoora campus)
Heh.
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Luck we argued about template strands. It was on there. :P
LOL
so lucky man.
I wrote the template strand for the "CODING" strand. and talked about the transcriptional process from there.
Did anyone mention 3-5 end.... i forgot about it . fml
I was talking about the multi choice Q...
Was the answer to that question like, UCG?
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Luck we argued about template strands. It was on there. :P
LOL
so lucky man.
I wrote the template strand for the "CODING" strand. and talked about the transcriptional process from there.
Did anyone mention 3-5 end.... i forgot about it . fml
I was talking about the multi choice Q...
Was the answer to that question like, UCG?
yeah...
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so, I would say that this thread was a success :)
awesome contribution from lots of people, good luck with your biology study scores...
it's so satisfying to have completed biology, and for me to never have to study it again....
I would also say, in my very best Borat accent...
GREAT SUCCESS!
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ha im sure your all glad its over
and some of you were stressing about microarrays lol
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ha im sure all glad its over
and some of you were stressing about microarrays lol
I think VCAA went out of their way to make sure this years exam was VERY clear and simple, especially after their last two attempts. Mid year and 09 end of year were shockers... One or two bad questions wreck everything.
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that benefits you then cause then you would know alot of the stuff on there... ah well im sure you all did great... too many smart people on here haha
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Well a big thanks to you TL and Russ. Both of your help has been amazing.
Couldn't have done it without your advice and knowledge.
Also thanks to anyone else who helped me out in Bio this year. I really appreciate it. :)
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Luck we argued about template strands. It was on there. :P
LOL
so lucky man.
I wrote the template strand for the "CODING" strand. and talked about the transcriptional process from there.
Did anyone mention 3-5 end.... i forgot about it . fml
I was talking about the multi choice Q...
Was the answer to that question like, UCG?
yeah...
Wasnt it AGT?????
wtf?
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RNA don't have any Ts bro...
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RNA don't have any Ts bro...
Didnt it ask for the Dna strrand from the possible amino acids?
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RNA don't have any Ts bro...
Didnt it ask for the Dna strrand from the possible amino acids?
Pretty sure it asked for the tRNA...
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RNA don't have any Ts bro...
Didnt it ask for the Dna strrand from the possible amino acids?
Pretty sure it asked for the tRNA...
FUKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
omg im so pissed
did so bad on the MC
-
don't worry its only MC I stuffed up heaps of short answer.... never touching evolution or meiosis again in my entire life
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don't worry its only MC I stuffed up heaps of short answer.... never touching evolution or meiosis again in my entire life
I think I did really well for mc, but just okay for sa
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Pretty sure it asked for the tRNA...
This is how i remember it too
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yea was tRNA :) i dont remember which answer i put, but was it the one which was a direct RNA conversion? ie. TTT into UUU?
and from me as well, thanks so much to all you biology brainiacs who helped me throughout the year, i very much doubt i would've got as high scores without you guys :)
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yea was tRNA :) i dont remember which answer i put, but was it the one which was a direct RNA conversion? ie. TTT into UUU?
and from me as well, thanks so much to all you biology brainiacs who helped me throughout the year, i very much doubt i would've got as high scores without you guys :)
Farking hell
im gonna go die
i hate everyone
i hate myself
i hate everything
i hate biology
so stupid
so useless
bye
im dieing
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oh come on matty smile :) is one mark, im sure you ripped the rest of it! i wish i could 50 in a subject (your psych)...
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RNA don't have any Ts bro...
Didnt it ask for the Dna strrand from the possible amino acids?
Pretty sure it asked for the tRNA...
FUKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
omg im so pissed
did so bad on the MC (out of 25)
well hey, that's better than doing bad for the SA (out of 50)...
*points at himself*
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yea was tRNA :) i dont remember which answer i put, but was it the one which was a direct RNA conversion? ie. TTT into UUU?
and from me as well, thanks so much to all you biology brainiacs who helped me throughout the year, i very much doubt i would've got as high scores without you guys :)
Farking hell
im gonna go die
i hate everyone
i hate myself
i hate everything
i hate biology
so stupid
so useless
bye
im dieing
haha, hey remember your perfect psych score so far.....
remember the likely 50... and relax.
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oh come on matty smile :) is one mark, im sure you ripped the rest of it! i wish i could 50 in a subject (your psych)...
Its not one mark
I rekon i dropped 6-8 Stupid mc.
and atleast 10 SA
ffsssssssssssssssssssss
another B+
fkkkkkkkkkkkkkkkkkkkkk
all those hours
guys im going off vn for a bit
talk to you in few DECADES WHEN IM DEAD
cye
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well talk to you tomorrow :) night
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Matt123 -> don't be too disheartened! I reckon the A+ cutoff will be around 59-60 although the exam was easyish, as there were quite a few subtle and some hard questions in there that many people would not have picked up. If you dropped 6 in MC and 10 in SA you may scrape an A+ or get an A, not a B+!
And remember you have other VCE subjects that you are going to gun!
so as cypriottiger says - relax man! you'll be fine, i expect you'll be pleasantly surprised with your study score
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Matt123 -> don't be too disheartened! I reckon the A+ cutoff will be around 59-60 although the exam was easyish, as there were quite a few subtle and some hard questions in there that many people would not have picked up. If you dropped 6 in MC and 10 in SA you may scrape an A+ or get an A, not a B+!
And remember you have other VCE subjects that you are going to gun!
so as cypriottiger says - relax man! you'll be fine, i expect you'll be pleasantly surprised with your study score
Cheers buddy , Appreciate it.
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The answers are correct. It is B.
I don't think so.
http://en.wikipedia.org/wiki/Coding_strand
I think the wording is incorrect, but (and this is a question not an argument) shouldn't the template run from the 3' -> 5' direction as the mRNA is constructed from the 5' -> 3'? Shouldn't you be able to deduce from that fact that the mRNA must in that direction, so B is correct?