Post by: Joseph41 on November 03, 2017, 09:16:32 am
COMPLETE SAMPLE SOLUTIONS HERE
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Post by: PhoenixxFire on November 03, 2017, 11:57:45 am
After all those immunity questions people were asking yesterday, the only short answer questions were on innate immunity.
What did people pick for MC Q40? I changed my mind last minute.
Post by: thushan on November 03, 2017, 12:09:54 pm
Post by: LPadlan on November 03, 2017, 12:24:31 pm
Post by: bingoman2000 on November 03, 2017, 12:24:45 pm
Post by: PhoenixxFire on November 03, 2017, 12:26:26 pm
Did everyone say c, for mc q13? It took me a while to get to that conclusionWhich question was that? I don't remember all the numbers.
Post by: Wendles278 on November 03, 2017, 12:28:09 pm
They gave us a 6 mark question that was about mass extinction of Australian MegaFauna. we had to read an excerpt of an article (something from The Conversation) and identify 3 points that provided evidence against the rapid extinction theory and why. It felt like an English exam >:(
After all those immunity questions people were asking yesterday, the only short answer questions were on innate immunity.
What did people pick for MC Q40? I changed my mind last minute.
OMG I so feel it's like they ran out of questions like what happened to apoptosis, signal transduction, photosynthese and cell two and translation or translation. There were so many better questions was so pushed for time because it was so wordy!!!
Post by: ezferns on November 03, 2017, 12:31:17 pm
Post by: Zaljc on November 03, 2017, 12:34:59 pm
Post by: Sam M on November 03, 2017, 12:35:05 pm
Post by: PhoenixxFire on November 03, 2017, 12:37:24 pm
omg on that question asking why one gene could produce multiple proteins, I've realised the answer is probably due to exon splicing. Do you think I would get any marks if I mentioned the actions of regulatory genes affecting other gene's expression? :oDepends on what exactly you wrote. Probably not. I knew straight away it was talking about exon splicing because I read it in another exam...there seemed to be lots of questions only slightly reworded from past exams.
Post by: PhoenixxFire on November 03, 2017, 12:38:58 pm
For Q13 I got D because below 10 arbitrary units, the rate of aerobic respiration would be higher than photosynthesis because more oxygen is being used than produced.if that's the question I think it is then I'm pretty sure that's what I picked too.
Post by: jaronmak on November 03, 2017, 12:43:00 pm
For the question with venom inhibitors, could you say it was humoral immunity?If you’re asking about which part of the immune system it was from, I said innate immune system because it also talked about cytokines and lysozymes
Post by: JaeSunRyoo on November 03, 2017, 12:43:21 pm
I can't remember what option c's answer was, tho.
There were a few questions that trundled me, like the one about the two control variables. I kinda feel like an idiot for not having answered that question satisfactorily, and realizing that one of the control variables I put in had already been answered by the question when the guy measured the O2/CO2/temperature for 4 mins without the cockroach in it.
Other than that... it wasn't too bad.
Post by: Roryr99 on November 03, 2017, 12:45:09 pm
Post by: LPadlan on November 03, 2017, 12:48:12 pm
if that's the question I think it is then I'm pretty sure that's what I picked too.I got c) 1/3 of point s or something. I assumed point s was around 0.18 and i divided by 3 resukting in 0.06. If you look at the graph it kinda makes sense. Hopefully Thushan can provide some clarifications
Post by: PhoenixxFire on November 03, 2017, 12:49:20 pm
Post by: JaeSunRyoo on November 03, 2017, 12:49:29 pm
If you’re asking about which part of the immune system it was from, I said innate immune system because it also talked about cytokines and lysozymes
You can say 2nd line of defence, right? That's what I said, and I'm pretty sure it falls under innate immunity...
I'm starting to feel anxious XD
Post by: JaeSunRyoo on November 03, 2017, 12:51:23 pm
Can you say amount of food coackroche consumes before testing each day and the same type of food consumed for two controlled variables?
I have a feeling I messed up that question now, lol.
I talked about humidity in the chamber given the distance of the heat lamp to the chamber and the amount of moisture in the air contributing to having an effect on relative cellular respiration on the cockroach, but I feel like I'm blabbing again. Not really sure, will be waiting to see solutions.
Post by: PhoenixxFire on November 03, 2017, 12:52:24 pm
You can say 2nd line of defence, right? That's what I said, and I'm pretty sure it falls under innate immunity...I just said innate immunity *gulp*. Fairly sure I messed up the question about why the gas levels in the rats container was measured for 4 min instead of one. It felt like I repeated the stem of the question.
I'm starting to feel anxious XD
The controlled variables I picked were way worse than the ones you used.
Post by: True Dat on November 03, 2017, 12:54:40 pm
I have a feeling I messed up that question now, lol.I'm guessing my answers of an Air tight container and Constant temperature are wrong then?
I talked about humidity in the chamber given the distance of the heat lamp to the chamber and the amount of moisture in the air contributing to having an effect on relative cellular respiration on the cockroach, but I feel like I'm blabbing again. Not really sure, will be waiting to see solutions.
Post by: PhoenixxFire on November 03, 2017, 12:57:02 pm
I had trouble determining the purpose of that group a caterpillar question hahaIt was a control - You can't know if they're going to eat 'less' if you don't know what normal is. I think I answered it badly though.
Post by: JaeSunRyoo on November 03, 2017, 12:57:38 pm
I'm guessing my answers of an Air tight container and Constant temperature are wrong then?
Air tight I think was already given since it said it was a "closed" chamber. That, and we don't want the cockroach to die, right? That being said, I don't think it would be in the chamber long enough to die from lack of 02, but... eh, I don't know, really. We'll have to see.
Constant temperature was one of the variables being tested. In the first part of the question, he tested the chamber without the cockroach for 4 mins, labeling the C02, 02 levels and the relative temperature. Even tho 02 levels decreased, I don't think constant temperature would've been a constant variable. I put that as a independent variable.
Post by: True Dat on November 03, 2017, 12:57:59 pm
It was a control - You can't know if they're going to eat 'less' if you don't know what normal is. I think I answered it badly though.I answered it with : To provide an example of what would happen over the 4 days without the presence of a caterpillar
Post by: Stolfin on November 03, 2017, 12:58:52 pm
1. the amount of ice around the chamber had to be consistant due to cooling temps differed
2. the food the cockroach ate had to be the same over the 6 days
i was effy about it tho :/
Post by: Ahmad_A_1999 on November 03, 2017, 12:59:23 pm
Post by: PhoenixxFire on November 03, 2017, 01:00:50 pm
The two controls i said was..I said the first one too I didn't even think about food - the other one I said was that the cockroach had to be kept in an environment of the same temperature whenever its not in the container - fairly sure it was wrong :-\
1. the amount of ice around the chamber had to be consistant due to cooling temps differed
2. the food the cockroach ate had to be the same over the 6 days
i was effy about it tho :/
Post by: JaeSunRyoo on November 03, 2017, 01:01:08 pm
The two controls i said was..
1. the amount of ice around the chamber had to be consistant due to cooling temps differed
2. the food the cockroach ate had to be the same over the 6 days
i was effy about it tho :/
Though the food thing is probably a good point that I should have fricking put in, not too sure about ice. I think it was assumed from the graphs that a consistent amount of ice would be placed in order to lower the temperature to 10 degrees Celsius... unless they're using a different form of ice?
Post by: PhoenixxFire on November 03, 2017, 01:01:59 pm
WELL... Did VCAA run out of questions or something, there was half the course missing and they replaced it with a 9 marker on Mega fauna extinctions :'( struggled with time too :-\I'm so mad about that - It didn't even really test our knowledge, it was more can you understand what you're reading. There's so many things they didn't cover too. I was expecting lots of experimental design but it was 2 long questions...
Post by: PhoenixxFire on November 03, 2017, 01:02:38 pm
Though the food thing is probably a good point that I should have fricking put in, not too sure about ice. I think it was assumed from the graphs that a consistent amount of ice would be placed in order to lower the temperature to 10 degrees Celsius... unless they're using a different form of ice?I wrote the same amount of ice because it didn't mention it taking the same amount of time to cool to 10 degrees.
Post by: JaeSunRyoo on November 03, 2017, 01:05:00 pm
I wrote the same amount of ice because it didn't mention it taking the same amount of time to cool to 10 degrees.
Hm... good point. I don't remember thinking about it that way, had a brain block in that question :/
In regards to the fauna question though, it seems like a massive giveaway of like 9 marks. Though I'm happy it was an easy slot of marks, it was quite disappointing.
That being said, the exam did feel a bit empty. Multiple choice did have a decent range, but the long answers seemed a bit... lacking.
Post by: jaronmak on November 03, 2017, 01:05:17 pm
You can say 2nd line of defence, right? That's what I said, and I'm pretty sure it falls under innate immunity...uhh I’m not too sure, because the lysozymes would’ve been a physical barrier from the first line of defence
I'm starting to feel anxious XD
I suppose it might be ok, but I guess we’ll have to wait for Thushan’s opinion or for VCAA to put out the examiners report
Post by: PhoenixxFire on November 03, 2017, 01:06:08 pm
uhh I’m not too sure, because the lysozymes would’ve been a physical barrier from the first line of defence
I suppose it might be ok, but I guess we’ll have to wait for Thushan’s opinion or for VCAA to put out the examiners report
When does the examiner report come out? Is it before we get our results or after?
Post by: K888 on November 03, 2017, 01:07:36 pm
From memory, it's after results. Takes a decent amount of time.
When does the examiner report come out? Is it before we get our results or after?
I could be wrong, though. :)
Post by: LPadlan on November 03, 2017, 01:09:10 pm
Depends on what exactly you wrote. Probably not. I knew straight away it was talking about exon splicing because I read it in another exam...there seemed to be lots of questions only slightly reworded from past exams.Wouldnt it be due to being a regulatory gene? A gene that produces proteins that controls other genes?
Post by: PhoenixxFire on November 03, 2017, 01:11:58 pm
Wouldnt it be due to being a regulatory gene? A gene that produces proteins that controls other genes?No. It talked about alternate proteins being produced. Regulatory genes make transcription factors that alter the rate of expression of a protein not the actual protein. (although I could be wrong - maybe they control exon splicing?)
Post by: sadcats_club on November 03, 2017, 01:15:26 pm
Post by: JaeSunRyoo on November 03, 2017, 01:16:15 pm
Eh..............
Post by: jaronmak on November 03, 2017, 01:17:02 pm
From memory, it's after results. Takes a decent amount of time.Yeah I'm pretty sure they take a while; I did psych last year and from memory the examiner's report didn't come out until about June this year :/
I could be wrong, though. :)
Post by: PhoenixxFire on November 03, 2017, 01:17:19 pm
For the control question at the end I had food given and relate it to glucose level and impact on cell resp rate, as well as time of day of experiment due to different metabolism rates of the cockroach at these different times...OMFG i wish I had a time machine. My brain was stuck on a loop about temperature. I wish I had thought of food.
Post by: JaeSunRyoo on November 03, 2017, 01:18:00 pm
For the control question at the end I had food given and relate it to glucose level and impact on cell resp rate, as well as time of day of experiment due to different metabolism rates of the cockroach at these different times...
It doesn't say anything about the cockroach being awake 24/7, and it did mention that the guy was trying to minimize or otherwise prevent the cockroach from being stressed. Sounds like a plausible answer, the 2nd part. Not sure what the examiners will think about it, though...
Post by: sagisingareddy on November 03, 2017, 01:28:17 pm
You can say 2nd line of defence, right? That's what I said, and I'm pretty sure it falls under innate immunity...
I'm starting to feel anxious XD
i think its innate first and second line, cuz lysozymes are first line defence
Post by: JaeSunRyoo on November 03, 2017, 01:32:12 pm
i think its innate first and second line, cuz lysozymes are first line defence
It was only mark, and the way it was asked, it seemed as if there was only one type of immunity they wanted in the answers...
¯\_(ツ)_/¯
Post by: PhoenixxFire on November 03, 2017, 01:32:41 pm
Post by: jaronmak on November 03, 2017, 01:33:45 pm
Innate system is the second line of defence. Lysozymes are part of the second line of defenceAren't lysozymes also in our tears, which would then mean it acts as part of the first line of defence, as a chemical barrier?
Post by: JaeSunRyoo on November 03, 2017, 01:36:19 pm
Post by: LPadlan on November 03, 2017, 01:36:31 pm
Aren't lysozymes also in our tears, which would then mean it acts as part of the first line of defence, as a chemical barrier?Yes, you're right. Had a bit of a brain-blank there. Innate =natural, non specific
Post by: sagisingareddy on November 03, 2017, 01:39:13 pm
It was only mark, and the way it was asked, it seemed as if there was only one type of immunity they wanted in the answers...
¯\_(ツ)_/¯
ahh dw, if u feel bad think abt how i lost marks on the first question which i wrote that the small hydrophobic substance doesnt need a carrier
:-[ :-[
Post by: Wendles278 on November 03, 2017, 01:44:28 pm
ahh dw, if u feel bad think abt how i lost marks on the first question which i wrote that the small hydrophobic substance doesnt need a carrier
:-[ :-[
Wait wouldn't it be the other way around as hydrophillic substances would be repelled by the hydrophobic fatty acids tail hence they need a protein channel. Whereas hydrophobic substances simiplying under diffusion.
Post by: vox nihili on November 03, 2017, 01:45:46 pm
Wait wouldn't it be the other way around as hydrophillic substances would be repelled by the hydrophobic fatty acids tail hence they need a protein channel. Whereas hydrophobic substances simiplying under diffusion.
You’re correct
Post by: vox nihili on November 03, 2017, 01:46:19 pm
Post by: LifeisaConstantStruggle on November 03, 2017, 02:00:13 pm
Post by: vox nihili on November 03, 2017, 03:20:55 pm
Post by: JaeSunRyoo on November 03, 2017, 03:24:15 pm
Our champion vox
Post by: Zaljc on November 03, 2017, 03:24:33 pm
Also, if I said innate immune response but then added (the second line of defence) in brackets, would I still get a mark for that? Because technically lysosomes aren’t part of the second line of defence but I did say innate
Post by: KANYEWEST on November 03, 2017, 03:26:42 pm
Post by: LifeisaConstantStruggle on November 03, 2017, 03:33:06 pm
What about the six marker question with the megafauna? What did everybody write for that?
Also, if I said innate immune response but then added (the second line of defence) in brackets, would I still get a mark for that? Because technically lysosomes aren’t part of the second line of defence but I did say innate
Absence of the fire plants and stuff
Coexisted for a long ass time
And small aboriginal population.
My bio terminologies are weird after the exam cuz I cbs doing it in detail HAHAHAHA
Post by: jaronmak on November 03, 2017, 03:35:34 pm
What about the six marker question with the megafauna? What did everybody write for that?For this question, the three pieces of evidence I used were:
- Aboriginal populations were small, so it is unlikely they could have caused significant damage to habitats and thus would likely not have caused mass extinctions
- The wombat mammal thing not dying until 33,000 years after or whatever; evidence that the First Aboriginals and some animal species were able to coexist peacefully, therefore mass extinction may not have been due to the First Aboriginals
- No evidence of fire-sensitive plants experiencing a genetic bottleneck; further evidence to support the fact that the First Aboriginals didn't necessarily burn the entire landscape and completely destroy habitats
It was a pretty weird question in my opinion, I wasn't really sure how they were expecting it to be answered so I just wrote that 😕
Post by: PhoenixxFire on November 03, 2017, 03:37:19 pm
Absence of the fire plants and stuffNow I feel a little better that's what I wrote too. I'm so pissed about that and like 4/5 pages of experimental design. I knew there would be a lot but that's crazy. So many things they could have assessed.
Coexisted for a long ass time
And small aboriginal population.
My bio terminologies are weird after the exam cuz I cbs doing it in detail HAHAHAHA
Post by: Zaljc on November 03, 2017, 03:38:08 pm
Post by: LifeisaConstantStruggle on November 03, 2017, 03:45:33 pm
Now I feel a little better that's what I wrote too. I'm so pissed about that and like 4/5 pages of experimental design. I knew there would be a lot but that's crazy. So many things they could have assessed.
Tbh yeah the experimental design stuff took the most time but it wasn't really unexpected tho the questions asked were quite predictable for experimental design (unless if you count the possible controlled variables then WOW)
And I wrote that the cockroach should be put in the chamber at the same time of the day due to probable difference in rate of respiration at day/night I wonder if it is correct or not : o
Post by: JaeSunRyoo on November 03, 2017, 04:12:16 pm
Would 45 megafauna already being extinct and megafauna was already declining in numbers before first Australians came to Australia be two distinct answers or are they kind of similar?
I wrote some stuff about the 45 megafauna already being extinct, but also had another point talking about how the presence of the wombat-like megafauna co-existing with the First Australians for 17000 years also meant that there were possibilities that the extinction model was incorrect.
It does seem a bit similar to me, though, what you wrote.
Post by: James Holgate on November 03, 2017, 04:17:55 pm
For megafauna I did;
•Fire plants didnt die out therefore megafauna eating them didnt die out
•Mega fauna going extinct before arrival of first australians
•Wombat thing and humans existing together for 17,000 years
For cockroach controls I did;
•Keep chamber air tight when putting the cockroach in to prevent gas exchange from occurring with the external environment
•Make the container small/restrict movement of cockroach—> if it moves more the rate of respiration will increase
Post by: PhoenixxFire on November 03, 2017, 04:33:08 pm
All those hours of studying spent on apoptosis, signalling molecules, specific immunity, fossils etc etc and THOSE are the questions they decide to give us? Stupid study design and its stupid dot points :( 😢Ikr I'm so annoyed. I crammed apoptosis because I didn't know it very well. No short answer on gene expression, apoptosis, acquired immunity...
Post by: JaeSunRyoo on November 03, 2017, 04:35:56 pm
Ikr I'm so annoyed. I crammed apoptosis because I didn't know it very well. No short answer on gene expression, apoptosis, acquired immunity...
But hey, some of it was on MC. A lot of things were still asked on MC.
Still, no short answers on those does suck...
Post by: Cloudy99 on November 03, 2017, 04:36:18 pm
Post by: neenah on November 03, 2017, 04:37:09 pm
Ikr I'm so annoyed. I crammed apoptosis because I didn't know it very well. No short answer on gene expression, apoptosis, acquired immunity...Instead they just tell us to define sterile... oh well just glad it's finally over and who knows if everyone seemed to find it somewhat difficult it may scale up quite a bit? Because honestly looking at this years questions and last year's questions, 2016 was much easier in my opinion
Post by: fluff on November 03, 2017, 04:40:10 pm
Post by: rainbowsparkles15 on November 03, 2017, 04:40:55 pm
They gave us a 6 mark question that was about mass extinction of Australian MegaFauna. we had to read an excerpt of an article (something from The Conversation) and identify 3 points that provided evidence against the rapid extinction theory and why. It felt like an English exam >:(
After all those immunity questions people were asking yesterday, the only short answer questions were on innate immunity.
What did people pick for MC Q40? I changed my mind last minute.
Cannot agree more!! The short answer missed so so so many points I thought would come up: allergies, adaptive immunity, apoptosis, types of fossils, vaccines, BMP4 and master genes, monoclonal antibodies HIV/MS, signal transduction, a 'typical' natural selection/ speciation question, designing an experiment and so many more! Then we get asked to define sterile :(((( Different to what I expected for sure
I thiiiink I put A for 40 but can't quite remember which q it was, what was it about?
Post by: neenah on November 03, 2017, 05:04:03 pm
Cannot agree more!! The short answer missed so so so many points I thought would come up: allergies, adaptive immunity, apoptosis, types of fossils, vaccines, BMP4 and master genes, monoclonal antibodies HIV/MS, signal transduction, a 'typical' natural selection/ speciation question, designing an experiment and so many more! Then we get asked to define sterile :(((( Different to what I expected for sureseeing all that content being listed like that makes me wanna cry :( I studied all those things so intensely and dedicated so much time but no. For nothing :( btw what was question 40? Also what did people get for question 39? Kinda confused my brain
I thiiiink I put A for 40 but can't quite remember which q it was, what was it about?
Post by: PhoenixxFire on November 03, 2017, 05:06:28 pm
Post by: captkirk on November 03, 2017, 05:07:18 pm
Post by: PhoenixxFire on November 03, 2017, 05:09:20 pm
Copy of the exams still isn't up? 🤔Vox is going to put up answers sometime tonight
Post by: K888 on November 03, 2017, 05:10:08 pm
Copy of the exams still isn't up? 🤔It's happening soon. Should be up within the next few hours.
And as PhoenixxFire said, vox nihili will put up answers tonight.
Post by: captkirk on November 03, 2017, 05:10:38 pm
Vox is going to put up answers sometime tonight
Hmm, I thought he would only put up the solutions.
Hopefully he puts up copy with solutions then :D
Post by: Roadrunnerani on November 03, 2017, 05:12:41 pm
- Seconary immune response (because Lysozymes are also technically found in the phagocytes)
- MegaFauna may have been docile as they'd never encountered humans before (increasing the liklihood that they'd be hunted)
- Antiseptics could be used to wash skin; disinfectant for hard surfaces (to clean for a hospital)
- Ethical issues: Should we tell the parents if the child carries a heritable disease? What happens if the disease doesn't develop (i.e. phenotype is also formed as part of an interaction with the enviroment)
- I said "Sterile means that the substance has no pathogens in it. In this context, the milk is not sterile."
Post by: ardria on November 03, 2017, 05:23:41 pm
Do these answers sound valid? They are the ones I'm not entirely confident in.
- MCQ 40: Last option which was that it was transgenic. My thinking was that it's transgenic because RNA is inserted into the plant, and the RNA is genetic material not usually found in the organism.
- The answer for the different proteins from one gene question could only have been alternative splicing of exons, sorry guys :(. I feel the vast majority of the state wouldn't have known this answer. I only knew cus I did some wider reading.
- I said: "innate, non-specific immunity (2nd line of defense)"
- For the question about antibody function, I answered with descriptions of both agglutination and neutralization of the specific antigen.
- Sterile meaning: 'No pathogenic microbes present, e.g. bacteria'.
- For hospital sterilization methods, I took a totally wild guess and said:
1. Frequent sanitisation/disinfection of surfaces using santising/disinfecting chemicals (hahaha). Then I explained how this prevents spread of germs.
2. Frequent hand-washing of staff, patients and visitors after coming into contact with sick people or contaminated objects.
- I thought the mass extinction of megafauna question was so silly! For the 3 marker bit I had to rush it so I said something like:
"Arrival of First humans and their behavior caused extinction of many megafauna due to behavior like excessive hunting. Their behaviour also resulted in damage to ecology and habitat destruction that caused megafauna to go extinct".
Which I felt was just paraphrasing half the passage? I had no idea how to hit that 3rd mark.
For the 6-marker I believe I did:
- Fire plants(?) not going through genetic bottleneck something something, because this means burning of the plants couldn't have damaged ecology
- Aborigine population not very big, because it's unlikely they would've had an impact great enough to cause mass extinctions
- Can't remember 3rd...I think it was about the megafauna and Aborigines not existing at the same time so Aborigines couldn't have caused their extinction
- For the cockroach experiment controlled variables (omg, this was tough), I put:
1. Same amount of food given to cockroach. Explanation was cus glucose from food is a reactant of cellular respiration so the amount of it affects rate of cellular respiration and thus O2 and CO2 levels.
2. Same level of activity cockroach is allowed to have. Because more activity > more the cockroach respires, affecting O2 and CO2 levels. Eeek, dunno about this one haha.
Post by: neenah on November 03, 2017, 05:28:26 pm
Post by: chrisjudd00 on November 03, 2017, 05:31:43 pm
Post by: PhoenixxFire on November 03, 2017, 05:34:53 pm
Post by: chrisjudd00 on November 03, 2017, 05:36:48 pm
Post by: JaeSunRyoo on November 03, 2017, 05:38:49 pm
Post by: chrisjudd00 on November 03, 2017, 05:40:32 pm
Post by: ardria on November 03, 2017, 05:52:00 pm
But that would mean the STR's from the child would have to come from the parents. Thus every number would have to be common with one of the parents and i didnt think they were but i could be wrong.
I chose the Individual 4/Parents 1 +2 answer as well simply because the child's STR markers were more similar to the parents' than the other similar answer.
Post by: Ahmad_A_1999 on November 03, 2017, 05:56:34 pm
I was unusually and extremely rushed for time. I was really careful doing MCQ because I could tell it was easy to trip up and pick the answer that "seemed" right if you rushed it. My examiner teacher said this was definitely an "unfair" exam in how mean and vague it suddenly became, especially compared to 2016's relative straight-forwardness.
Do these answers sound valid? They are the ones I'm not entirely confident in.
- MCQ 40: Last option which was that it was transgenic. My thinking was that it's transgenic because RNA is inserted into the plant, and the RNA is genetic material not usually found in the organism.
- The answer for the different proteins from one gene question could only have been alternative splicing of exons, sorry guys :(. I feel the vast majority of the state wouldn't have known this answer. I only knew cus I did some wider reading.
- I said: "innate, non-specific immunity (2nd line of defense)"
- For the question about antibody function, I answered with descriptions of both agglutination and neutralization of the specific antigen.
- Sterile meaning: 'No pathogenic microbes present, e.g. bacteria'.
- For hospital sterilization methods, I took a totally wild guess and said:
1. Frequent sanitisation/disinfection of surfaces using santising/disinfecting chemicals (hahaha). Then I explained how this prevents spread of germs.
2. Frequent hand-washing of staff, patients and visitors after coming into contact with sick people or contaminated objects.
- I thought the mass extinction of megafauna question was so silly! For the 3 marker bit I had to rush it so I said something like:
"Arrival of First humans and their behavior caused extinction of many megafauna due to behavior like excessive hunting. Their behaviour also resulted in damage to ecology and habitat destruction that caused megafauna to go extinct".
Which I felt was just paraphrasing half the passage? I had no idea how to hit that 3rd mark.
For the 6-marker I believe I did:
- Fire plants(?) not going through genetic bottleneck something something, because this means burning of the plants couldn't have damaged ecology
- Aborigine population not very big, because it's unlikely they would've had an impact great enough to cause mass extinctions
- Can't remember 3rd...I think it was about the megafauna and Aborigines not existing at the same time so Aborigines couldn't have caused their extinction
- For the cockroach experiment controlled variables (omg, this was tough), I put:
1. Same amount of food given to cockroach. Explanation was cus glucose from food is a reactant of cellular respiration so the amount of it affects rate of cellular respiration and thus O2 and CO2 levels.
2. Same level of activity cockroach is allowed to have. Because more activity > more the cockroach respires, affecting O2 and CO2 levels. Eeek, dunno about this one haha.
Hahahaha this is so relatable, the trial exams I was doing I could finish with an hour left, I don't know what happened today :( and yeah 2016 was easier for sure
Post by: VH on November 03, 2017, 05:59:32 pm
Post by: PhoenixxFire on November 03, 2017, 06:01:24 pm
Post by: ardria on November 03, 2017, 06:01:54 pm
Hahahaha this is so relatable, the trial exams I was doing I could finish with an hour left, I don't know what happened today :( and yeah 2016 was easier for sure
Same for me! I was finishing significantly early in trial exams but finished seconds before time was up today. I think it was largely because only like 5% of the MCQ were ones you could skim-read and know the definite answer, whereas I was used to it being more like 30-40% or something in trial exams.
Also a lot of the short answer questions had long and detailed premises that you had to read fully to make sure you weren't going to make a wrong assumption, e.g. the runner/ramet one where the questions were straightforward and quite simple but you had to read and digest so much text.
I feel like the style of this exam made it more advantageous to know extension stuff and general knowledge of the world (e.g. the sterilization stuff) I feel like this was one of those exams where doing 150 practice exams wouldn't have been significantly more advantageous than doing like 15. Like, you could've done 150 practice exams (not that I did this many) and still struggled. Am I the only one that feels this way?
Post by: rainbowsparkles15 on November 03, 2017, 06:03:06 pm
For the cockroach controls:
-Same diet/ amount of food
-Same amount of exercise (though I'm not sure how this could be tested!)
For the same gene but different proteins:
-Alternative exon splicing but not sure how to get 3 marks out of this?
For the STR multiple choice (Q39):
-D, Individual 4's parents are 1&2
Multiple choice 40:
-Think I chose the transgenic option, D, but quite unsure!
6 mark extinction:
-Not very big population so unlikely to cause mass extinction
-Evidence they coexisted (wombat mammal or something)
-Evidence that they had died out tens of thousands of years earlier so First Australians didn't cause extinction
Type of immune system:
Innate
Post by: ardria on November 03, 2017, 06:05:45 pm
How did everyone answer the 3 mark question asking how amino acids were joined?
I word-vomited all this Chemistry 3/4 stuff cus I had no idea what the 3 marks were for.
- Condensation reaction where amine group of amino acid joined with carboxyl group of another amino acid.
- H2O molecule removed
- Resulting bond is peptide bond which is a covalent bond
Woohoo I said exact same thing.
For the cockroach controls:
-Same diet/ amount of food
-Same amount of exercise (though I'm not sure how this could be tested!)
I don't remember it being 3 marks but I explained in detail what the process entailed.
For the same gene but different proteins:
-Alternative exon splicing but not sure how to get 3 marks out of this?
Post by: Ahmad_A_1999 on November 03, 2017, 06:10:04 pm
Same for me! I was finishing significantly early in trial exams but finished seconds before time was up today. I think it was largely because only like 5% of the MCQ were ones you could skim-read and know the definite answer, whereas I was used to it being more like 30-40% or something in trial exams.
Also a lot of the short answer questions had long and detailed premises that you had to read fully to make sure you weren't going to make a wrong assumption, e.g. the runner/ramet one where the questions were straightforward and quite simple but you had to read and digest so much text.
I feel like the style of this exam made it more advantageous to know extension stuff and general knowledge of the world (e.g. the sterilization stuff) I feel like this was one of those exams where doing 150 practice exams wouldn't have been significantly more advantageous than doing like 15. Like, you could've done 150 practice exams (not that I did this many) and still struggled. Am I the only one that feels this way?
Yes! There was so much they left out, apoptosis, photosynthesis, signal transduction, allergic response, etc. A lot of my answers were iffy :(
How did everyone answer the 3 mark question asking how amino acids were joined?
For the cockroach controls:
-Same diet/ amount of food
-Same amount of exercise (though I'm not sure how this could be tested!)
For the same gene but different proteins:
-Alternative exon splicing but not sure how to get 3 marks out of this?
For the STR multiple choice (Q39):
-D, Individual 4's parents are 1&2
Multiple choice 40:
-Think I chose the transgenic option, D, but quite unsure!
6 mark extinction:
-Not very big population so unlikely to cause mass extinction
-Evidence they coexisted (wombat mammal or something)
-Evidence that they had died out tens of thousands of years earlier so First Australians didn't cause extinction
Type of immune system:
Innate
For the amino acid question I just talked about the whole translation process and made sure to mention that they join in a condensation polymerisation reaction and the amino acids are joined by peptide links
Post by: Ahmad_A_1999 on November 03, 2017, 06:11:23 pm
Did anyone talk about translation for this question??
Yeah I was thinking of doing this too hahahaha, but I didn't because I was scared that the amino group and carboxyl group stuff was too much for bio
Post by: Hydroxyl on November 03, 2017, 06:12:43 pm
I only did get the first 14 pages of the exam before I got caught aha, the teacher needed to go to a meeting and let me take pictures but it was too late.
Viewable here:
https://ibb.co/bVwqdG
https://ibb.co/kgRZ5w
https://ibb.co/nwY3yG
https://ibb.co/cZ33yG
https://ibb.co/dUq5Cb
https://ibb.co/nbUMkw
https://ibb.co/j3wOyG
https://ibb.co/krY3yG
https://ibb.co/ea55Cb
https://ibb.co/eVs7Qw
https://ibb.co/kRaiyG
https://ibb.co/id8QCb
https://ibb.co/e2A5Cb
https://ibb.co/cy11kw
Post by: James Holgate on November 03, 2017, 06:13:21 pm
For multiple choice I had individual 4 being child of 1 & 2
And for the last one I can’t remember the answer I chose but I remember specifically choosing NOT transgenic, because the dsRNA didnt enter the plants genome, it just entered the cell, and bound to viral RNA that also entered the cell..........I could be completely wrong thats just how I interpreted the question 🤷🏽♂️
Post by: TRA0023 on November 03, 2017, 06:15:47 pm
Post by: Zaljc on November 03, 2017, 06:16:18 pm
Transgenic is when genetic material is inserted to the actual DNA of the organism, right?
I chose B because I thought the spray initiates changes that does effect translation of the viral gene because it said “the dsRNA silences a gene FROM the virus” not the plant
God, this is making me so anxious
Post by: James Holgate on November 03, 2017, 06:23:08 pm
Also I had NO IDEA on MC q24 about multiple sclerosis and what they would find in tissue...I think I guessed Th cells in the spinal fluid
What did you guys put?
Post by: PhoenixxFire on November 03, 2017, 06:23:45 pm
Not sure on A/B I chose A because B said that it bound to viral RNA presenting translation but the stem said something about the RNA breaking down...but then A made no sense to me so now I'm thinking it's B
Post by: PhoenixxFire on November 03, 2017, 06:24:28 pm
Ahh good to see some other non-transgenic answers!I picked the Th cell one too, not because I thought it was right but because I though the others were wrong
Also I had NO IDEA on MC q24 about multiple sclerosis and what they would find in tissue...I think I guessed Th cells in the spinal fluid
What did you guys put?
Post by: neenah on November 03, 2017, 06:31:20 pm
Post by: Ahmad_A_1999 on November 03, 2017, 06:35:43 pm
Also in short answers,my friends kind of confused me in the genetic screening question. Apparently i cant say an ethical implication is the decision of termination/abortion of the baby as it is a NEWBORN baby so the baby is already born. Are they reading to deep into the question or is this what most people thought of the question?OMG I freaked about this in the exam too hahaha, I was going to say the abortion stuff, but I think your friends are right in saying it is a newborn and you can't say that, I don't know, could be wrong though.
Post by: PhoenixxFire on November 03, 2017, 06:36:12 pm
I word-vomited all this Chemistry 3/4 stuff cus I had no idea what the 3 marks were for.I wrote about that and I don't do chem
- Condensation reaction where amine group of amino acid joined with carboxyl group of another amino acid.
- H2O molecule removed
- Resulting bond is peptide bond which is a covalent bond
Woohoo I said exact same thing.
I don't remember it being 3 marks but I explained in detail what the process entailed.
Post by: PhoenixxFire on November 03, 2017, 06:37:13 pm
What did people say for that majorly stuffed up one about MS and the bacteria????which question was this?
Post by: TRA0023 on November 03, 2017, 06:39:06 pm
I think I got the answer with individual one as well but there was another option that had me thinking and I was so confused man. As for the trials, pfft I would literally finish multiple choice in like 30-40 minutes and have so much time left for short answer! I think its because this was the actual exam that I would read the question a few times and look at every single option and analyse it rather then being quick, because I wanted to make sure my answer was as accurate as possible. Also in short answers,my friends kind of confused me in the genetic screening question. Apparently i cant say an ethical implication is the decision of termination/abortion of the baby as it is a NEWBORN baby so the baby is already born. Are they reading to deep into the question or is this what most people thought of the question?
Not too sure about abortion, as it is indeed a newborn...
I said privacy of the information obtained (insurance company, future employer etc.) and the baby not consenting to the test? violation of bodily autonomy? idk... i kinda winged the second one.
Post by: JaeSunRyoo on November 03, 2017, 06:39:59 pm
which question was this?
I think they might be talking about the "Hygiene" approach question concerning the MS context. The question was like "What can you understand/infer from this block of text?" The answer I put down was something like being exposed to this bacterial infection will help against MS or something, time to look at the screenshots that have been put up...
Post by: PhoenixxFire on November 03, 2017, 06:40:57 pm
Post by: LifeisaConstantStruggle on November 03, 2017, 06:41:10 pm
I word-vomited all this Chemistry 3/4 stuff cus I had no idea what the 3 marks were for.
- Condensation reaction where amine group of amino acid joined with carboxyl group of another amino acid.
- H2O molecule removed
- Resulting bond is peptide bond which is a covalent bond
Woohoo I said exact same thing.
Oo damn same. But because it said "join amino acids together" and I didn't know how many so I included "the repetition of the same reaction called condensation polymerisation occurs" just in case.
Post by: PhoenixxFire on November 03, 2017, 06:42:28 pm
I think they might be talking about the "Hygiene" approach question concerning the MS context. The question was like "What can you understand/infer from this block of text?" The answer I put down was something like being exposed to this bacterial infection will help against MS or something, time to look at the screenshots that have been put up...Ohhh the multi choice one about the 30% thing in people who had been infected with the bacteria as a child
Post by: JaeSunRyoo on November 03, 2017, 06:43:19 pm
Post by: LifeisaConstantStruggle on November 03, 2017, 06:43:36 pm
Not too sure about abortion, as it is indeed a newborn...
I said privacy of the information obtained (insurance company, future employer etc.) and the baby not consenting to the test? violation of bodily autonomy? idk... i kinda winged the second one.
Oo I wrote "inducing emotional stress to the parent/child should a positive test for a genetic disease is examined"or something along the lines of it, not sure tho.
Post by: PhoenixxFire on November 03, 2017, 06:44:27 pm
Yeah, Q25 on the MC, I think I put down D since it made the most sense to me.Thats what I picked
Post by: rainbowsparkles15 on November 03, 2017, 06:45:32 pm
Ahh good to see some other non-transgenic answers!
Also I had NO IDEA on MC q24 about multiple sclerosis and what they would find in tissue...I think I guessed Th cells in the spinal fluid
What did you guys put?
Same here :)
Post by: James Holgate on November 03, 2017, 06:46:10 pm
-Will be discriminated against by health insurance company if person has genetic disease susceptibility
-People won’t want to have kids with the person as their offspring could have the disease—>this reduces the genetic diversity in the population
Edit: here’s q24
Multiple sclerosis is an autoimmune disease. In sufferers of MS, the myelin coating of a nerve cell axons us damaged. This damage results in poor transmissiln of nerve messages between the brain, spinal chord and the rest of the body. One aspect of MS diagnosis is imaging the brain to detect visible areas of demylenation, called plaques.
•Researchers investingating MS have analysed various tissue samples from patients, in these samples they would expect to find;
A—An abundance of allergens in nerve cells
B—Cancer cells in MS plaques in brain tissue
C—Increased numbers of T helper cells in spinal fluid
D—An absence of T cytotoxic cells in the spinal chord and brian
.....I picked C at a guess
Post by: neenah on November 03, 2017, 06:50:30 pm
And for the amino acid question I said the same thing about a condesnation reaction and the amine group and the carboxylic group joining together to form a covalent bond (peptide bond) and water (I used H2O in the exam since VCAA looove repeating every year that students should be more confident using abbreviations) being a by product. And for the abortion thing, well just great. I swear time was scaring me so much I hope I can get used to time managment in year 12
Post by: LifeisaConstantStruggle on November 03, 2017, 06:51:57 pm
•The MS question was q24 of multiple choiceNot sure about the second one you wrote(?) As it is the genetic screening of newborn babies so the baby has been born before genetic screening.
•For genetic screening implications I put;
-Will be discriminated against by health insurance company if person has genetic disease susceptibility
-People won’t want to have kids with the person as their offspring could have the disease—>this reduces the genetic diversity in the population
Post by: rainbowsparkles15 on November 03, 2017, 06:52:27 pm
•The MS question was q24 of multiple choice
•For genetic screening implications I put;
-Will be discriminated against by health insurance company if person has genetic disease susceptibility
-People won’t want to have kids with the person as their offspring could have the disease—>this reduces the genetic diversity in the population
Glad someone else said the health insurance discrimination too, I was worried it was social and not ethical. I also said the newborn cannot provide its own consent regarding testing (pretty sure this was an answer on last years exam for the back page but could be wrong haha)
Post by: PhoenixxFire on November 03, 2017, 06:53:04 pm
Wait for mcq40, D was the first option I ruled out but now I'm starting to doubt my answer. I'm pretty sure I remember the actual question is what lead me to rule out DD was definitely wrong. It stated that the organism was transgenic but the stem clearly stated that its DNA did not change
And for the amino acid question I said the same thing about a condesnation reaction and the amine group and the carboxylic group joining together to form a covalent bond (peptide bond) and water (I used H2O in the exam since VCAA looove repeating every year that students should be more confident using abbreviations) being a by product. And for the abortion thing, well just great. I swear time was scaring me so much I hope I can get used to time managment in year 12
Post by: ardria on November 03, 2017, 06:53:36 pm
I wrote about that and I don't do chem
I'm not too sure about what people have said about describing translation, cus it said the "reaction" that joins 2 amino acids and I don't think that would be asking for translation.
Also, I'm now totally convinced that the transgenic answer was wrong for MCQ40 haha. Didn't realise transgenic had to involve the genome!
I totally missed that the genetic screening question said "ethical implications", and one of my answers was that genetic screening could have negative health effects that are not known, whether they short-term or long-term. Could this be considered an ethical implication or would it just be wrong?
My other answer was that it causes emotional distress to parents, possibly leading to depression.
Post by: vox nihili on November 03, 2017, 06:53:43 pm
2 B
3 D
4 C
5 B
6 C
7 C
8 D
9 A
10 C
Post by: James Holgate on November 03, 2017, 06:55:46 pm
Not sure about the second one you wrote(?) As it is the genetic screening of newborn babies so the baby has been born before genetic screening.
Nah like the baby’s future kids might have the disease so nobody will want to breed with the baby when it grows up is what I meant......I hope the examiners can see that lol
Post by: LifeisaConstantStruggle on November 03, 2017, 06:56:35 pm
Post by: vox nihili on November 03, 2017, 07:03:51 pm
12 C
13 D
14 B
15 D
16 D
17 C
18 A
19 D
20 B
Post by: goldencale on November 03, 2017, 07:09:35 pm
I ended up going with the stomach ulcers option (c) rather than D because the question said MS individuals had a 30% lower rate of infection. From that I assumed that they had a stronger specific immune response to the bacteria, resulting from previous exposure via the stomach ulcers.
Thoughts?
Post by: Roadrunnerani on November 03, 2017, 07:12:16 pm
My understanding is that using a greater amount of substrate would not increase the reaction rate, as there are limitied enzymes.
However increasing the concentration of catalase (option A) would lead to a greater rate of the production of oxygen?
Post by: vox nihili on November 03, 2017, 07:12:36 pm
22 B
23 B
24 C
25 D
26 A
27 A
28 D
29 C
30 C
31 A
That's all I've got at the moment. When I get the entire exam I'll finish off the results.
There's a potential that question 22 will be struck off. Macrophages are capable of producing interferon. Indeed, anyone who has ever been tested for TB will have potentially had a blood test that relies on the fact that macrophages produce interferon. This is outside the VCE course; however, someone may encourage them to revisit this question, as their answer is technically flawed.
Regarding MC Q25 about MS and hygiene,
I ended up going with the stomach ulcers option (c) rather than D because the question said MS individuals had a 30% lower rate of infection. From that I assumed that they had a stronger specific immune response to the bacteria, resulting from previous exposure via the stomach ulcers.
Thoughts?
Infection with H.pylori does not necessarily mean the development of stomach ulcers. You're right though, they should have used the word colonisation instead of infection. Many patients with H.pylori end up with gastritis instead of stomach ulcers.
Post by: jaronmak on November 03, 2017, 07:14:43 pm
1 AJust with Q10, wouldn't the answer be D, because C implies that the electron transport chain is occurring, and Y isn't technically pointing to the proteins on the plasma membranes, where the electron transport chain occurs?
2 B
3 D
4 C
5 B
6 C
7 C
8 D
9 A
10 C
Post by: LifeisaConstantStruggle on November 03, 2017, 07:15:01 pm
Hey Vox are you sure question 6 is c?
My understanding is that using a greater amount of substrate would not increase the reaction rate, as there are limitied enzymes.
However increasing the concentration of catalase (option A) would lead to a greater rate of the production of oxygen?
The substrate level was kept constant so the volume of oxygen released would eventually reach the same point if you go far enough if you increase the amount of enzymes.
But if you change the amount of substrate the rate will go higher and you will get more oxygen.
Post by: PhoenixxFire on November 03, 2017, 07:15:43 pm
Hey Vox are you sure question 6 is c?It has to be C. The graph shows the amount of O2 produced NOT the rate of the reaction, therefore when the graph levels off, all of the substrate has been used. The only way to increase this level is to add more substrate
My understanding is that using a greater amount of substrate would not increase the reaction rate, as there are limitied enzymes.
However increasing the concentration of catalase (option A) would lead to a greater rate of the production of oxygen?
Post by: vox nihili on November 03, 2017, 07:16:57 pm
Just with Q10, wouldn't the answer be D, because C implies that the electron transport chain is occurring, and Y isn't technically pointing to the proteins on the plasma membranes, where the electron transport chain occurs?
Unfortunately not. The proteins are located in the cristae.
It has to be C. The graph shows the amount of O2 produced NOT the rate of the reaction, therefore when the graph levels off, all of the substrate has been used. The only way to increase this level is to add more substrateThe graph does show the rate too; there's just no change (suggesting that the amount of enzyme is kept constant). You're right though :)
Post by: Joseph41 on November 03, 2017, 07:19:01 pm
Post by: LPadlan on November 03, 2017, 07:19:32 pm
11 DHey Vox, are you sure question 13 is d? I chose c as point p is around 0.18 and s is around 0.06
12 C
13 D
14 B
15 D
16 D
17 C
18 A
19 D
20 B
Post by: goldencale on November 03, 2017, 07:21:12 pm
Infection with H.pylori does not necessarily mean the development of stomach ulcers. You're right though, they should have used the word colonisation instead of infection. Many patients with H.pylori end up with gastritis instead of stomach ulcers.
Thanks for explaining, but what information in the stem suggests that childhood infection helps protect against MS?
Post by: Roryr99 on November 03, 2017, 07:21:41 pm
Also why is 25 not C?
Post by: Pandable on November 03, 2017, 07:25:20 pm
Why is question 12 multi choice C and not B? chloroplasts do not have a single circular chromosome, but many circular chromosomes, and they do reproduce by dividing in half?Yes Chloroplasts do have circular chromosomes and for question 25 people with stomach ulcers have a slight immunity to MS as 30% of the women with MS didnt have Stomach Ulcers
Also why is 25 not C?
Post by: Roryr99 on November 03, 2017, 07:26:18 pm
Post by: vox nihili on November 03, 2017, 07:27:14 pm
1 A
2 B
3 D
4 C
5 B
6 C
7 C
8 D
9 A
10 C
11 D
12 C
13 D
14 B
15 D
16 D
17 C
18 A
19 D
20 B
21 C
22 B
23 B
24 C
25 D
26 A
27 A
28 D
29 C
30 C
31 A
32 B
33 C
34 D
35 B
36 B
37 D
38 B
39 D
40 B
Post by: Pandable on November 03, 2017, 07:28:03 pm
It says "SINGLE" circular chromosomeYes Most chloroplast only have 1 Circular Plasmid or Chromosome
Post by: PhoenixxFire on November 03, 2017, 07:28:39 pm
Thanks for explaining, but what information in the stem suggests that childhood infection helps protect against MS?It says that of those with MS 30% less had the childhood infection than those without MS.
Post by: ardria on November 03, 2017, 07:33:29 pm
I was debating whether it was A or B and decided A as it was debatable whether what was listed would be considered "highly developed". Also because a larger brain is needed to be capable of speech (which is needed to have burial rites, as a previous VCAA exam directly suggested) and to make complex tools.
Post by: chrisjudd00 on November 03, 2017, 07:35:16 pm
Post by: Pandable on November 03, 2017, 07:36:24 pm
Why is 36 not A?I will tell you this, (its not something biologist admit) but Neaderthals had larger brains then us, we just had more of our brain allocated to complex thinking rather then memory storage
I was debating whether it was A or B and decided A as it was debatable whether what was listed would be considered "highly developed". Also because a larger brain is needed to be capable of speech (which is needed to have burial rites, as a previous VCAA exam directly suggested) and to make complex tools.
Post by: waterangel82 on November 03, 2017, 07:37:22 pm
Thank you for the answers. I'm pretty happy with getting 39/40 for MC, but I don't really understand question 8 for the pH meter, because aren't instruments calibrated to ensure better precision. But then again, I did search up pH meter calibration, and it said that it was calibrated to ensure accurate results. Is it alright if you could explain to me? Thanks!
Post by: LifeisaConstantStruggle on November 03, 2017, 07:37:51 pm
Post by: PhoenixxFire on November 03, 2017, 07:39:25 pm
Post by: PhoenixxFire on November 03, 2017, 07:41:33 pm
Post by: James Holgate on November 03, 2017, 07:41:35 pm
I will tell you this, (its not something biologist admit) but Neaderthals had larger brains then us, we just had more of our brain allocated to complex thinking rather then memory storage
For neanderthal question I chose they had evidence of culture...?
Post by: ardria on November 03, 2017, 07:42:05 pm
Hi Vox,
Thank you for the answers. I'm pretty happy with getting 39/40 for MC, but I don't really understand question 8 for the pH meter, because aren't instruments calibrated to ensure better precision. But then again, I did search up pH meter calibration, and it said that it was calibrated to ensure accurate results. Is it alright if you could explain to me? Thanks!
That has to do with the definitions of precision and accuracy.
Precision: e.g. if you repeat a measurement, the machine will produce the same measurement each time. This measurement could be wrong (inaccurate), but the machine is precise.
Accuracy: whether the measurement is factually corrected or not. E.g. if a student is conducting a test for the optimum pH of human body enzymes and the results suggested it was 25 degrees, this would be inaccurate as it goes against fact.
Post by: Pandable on November 03, 2017, 07:43:05 pm
For neanderthal question I chose they had evidence of culture...?Sorry i was not clear enough yes the answer is that they had evidence of culture
Post by: Joseph41 on November 03, 2017, 07:43:23 pm
https://atarnotes.com/forum/index.php?topic=174920.msg1000351#msg1000351
Post by: ardria on November 03, 2017, 07:44:08 pm
For neanderthal question I chose they had evidence of culture...?
I'm not really sure what Pandable is trying to say because I said I chose the answer about bigger brains haha, because both culture and complex tool making needs a developed brain.
I didn't choose the "highly developed culture" answer because it didn't seem like you could confirm that it was "highly developed".
I'm trying to understand why it would definitely be B but I don't get why A is wrong :-\
Post by: vazi on November 03, 2017, 07:44:31 pm
Post by: PhoenixxFire on November 03, 2017, 07:46:00 pm
I'm not really sure what Pandable is trying to say because I said I chose the answer about bigger brains haha, because both culture and complex tool making needs a developed brain.All the things listed in the stem indicate a highly developed culture.
I didn't choose the "highly developed culture" answer because it didn't seem like you could confirm that it was "highly developed".
Post by: Pandable on November 03, 2017, 07:46:57 pm
I'm not really sure what Pandable is trying to say because I said I chose the answer about bigger brains haha, because both culture and complex tool making needs a developed brain.Well let me be clear, we already know they have big brains, but we previously thought they were culturally inferior, bigger brain does not necessarily=complex brain.
I didn't choose the "highly developed culture" answer because it didn't seem like you could confirm that it was "highly developed".
Post by: PhoenixxFire on November 03, 2017, 07:48:01 pm
Could 37 be B since it says yellow virus fever is transmitted by mosquitoes?I thought about that. But it says primarily spread by mozzies not only spread by them. Also D is more right.
Post by: vox nihili on November 03, 2017, 07:55:32 pm
Could 37 be B since it says yellow virus fever is transmitted by mosquitoes?
I thought about that. But it says primarily spread by mozzies not only spread by them. Also D is more right.
This was one I had to think about a bit. The most compelling reason for me is that we don't know whether other parts of Brazil have those mosquitoes do. In the absence of that info, we have to assume they do and that therefore when people travel there, they can be better by mosquitoes, loading those mosquitoes up to the virus, which then spread it to other people.
Post by: PhoenixxFire on November 03, 2017, 07:58:25 pm
Would everyone prefer that I slowly trickled out the short answer questions one by one, or uploaded a document when I've completed them later tongiht (hopefully)?Whichever results in us getting them faster overall. ;D thanks Vox!!
Post by: PhoenixxFire on November 03, 2017, 08:00:06 pm
guys so for question 2d) about the possible effects of phenolic acid, what was a good answer?? I made it up and said something about a substance produced that wasnt tasty for the caterpillar??Thats what I said! I had no idea either
Post by: Sine on November 03, 2017, 08:01:43 pm
A and C are wrong for obvious reasons
B: The quesiton says "this outbreak was reported to be spreading to other areas of brazil" so people leaving and moving will faciliate the spread. - can go either way True/False
D: True
So go with most correct answer :P
Post by: ardria on November 03, 2017, 08:02:07 pm
Post by: NASA on November 03, 2017, 08:03:44 pm
Depends on what exactly you wrote. Probably not. I knew straight away it was talking about exon splicing because I read it in another exam...there seemed to be lots of questions only slightly reworded from past exams.
can you say how different chaperone molecules in the different cells will fold the polypeptide differently into the teritary 3d shape, therfore the shape and function of the protein will change, and the protein will be different even though its the same gene
Post by: Aar0n_101 on November 03, 2017, 08:03:53 pm
Would everyone prefer that I slowly trickled out the short answer questions one by one, or uploaded a document when I've completed them later tongiht (hopefully)?Prefer that it be uploaded as a whole document, thanks brother
This was one I had to think about a bit. The most compelling reason for me is that we don't know whether other parts of Brazil have those mosquitoes do. In the absence of that info, we have to assume they do and that therefore when people travel there, they can be better by mosquitoes, loading those mosquitoes up to the virus, which then spread it to other people.
Post by: NASA on November 03, 2017, 08:04:04 pm
Depends on what exactly you wrote. Probably not. I knew straight away it was talking about exon splicing because I read it in another exam...there seemed to be lots of questions only slightly reworded from past exams.
can you say how different chaperone molecules in the different cells will fold the polypeptide differently into the teritary 3d shape, therfore the shape and function of the protein will change, and the protein will be different even though its the same gene
Post by: waterangel82 on November 03, 2017, 08:04:47 pm
Thats what I said! I had no idea either
I said that the greater concentration of phenolic acid helped to activate genes which then produced a greater amount of protein products which were toxic to the caterpillars, so therefore they fed on mature leaves as they weren't so toxic.
Post by: Bianca12345 on November 03, 2017, 08:05:26 pm
One document would be clearer I say! Thank you!
Would everyone prefer that I slowly trickled out the short answer questions one by one, or uploaded a document when I've completed them later tongiht (hopefully)?
Post by: Sine on November 03, 2017, 08:08:05 pm
can you say how different chaperone molecules in the different cells will fold the polypeptide differently into the teritary 3d shape, therfore the shape and function of the protein will change, and the protein will be different even though its the same genewhich question was this? from what I remember alternative splicing was the correct "most obvious" answer and VCAA usually love the simple answers. You could possibly still get marks for an alternative answer (depends on how the question was worded)
also wow never ever seen a 6 marker on a bio exam before iirc i genuinely thought the max they do is a 4 markers (or 5) (having seen all the exams from 1997-2016)
Post by: vazi on November 03, 2017, 08:10:46 pm
Post by: waterangel82 on November 03, 2017, 08:11:09 pm
can you say how different chaperone molecules in the different cells will fold the polypeptide differently into the teritary 3d shape, therfore the shape and function of the protein will change, and the protein will be different even though its the same gene
Talking about very similar questions, I laughed silently ;D when I saw that multi choice question 11 on animal cells being exposed to radioactive oxygen (so similar to the multi choice on plant cells being exposed to radioactive oxygen a few years ago) :P
Post by: ringring on November 03, 2017, 08:13:19 pm
Post by: waterangel82 on November 03, 2017, 08:14:51 pm
That’s what I said- I’m confused because this whole exon splicing thing producing different proteins isn’t in the study design or vcaa approved textbooks
Actually, it's in Nature of Biology 2.
Post by: Aar0n_101 on November 03, 2017, 08:15:41 pm
wait will the section B answers be uploaded as well or have I missed them?answers for section b will be up later tonight hopefully
Post by: vox nihili on November 03, 2017, 08:19:13 pm
Author comments in [brackets].
1)
a)
i) The arrow should point downwards from the extracellular environment to the intracellular environment and should cross the phospholipid component of the membrane.
ii) The concentration of the molecular is higher in the extracellular environment than in the intracellular; therefore, it will diffuse from the latter to the former down its concentration gradient. Owing to its hydrophobicity, it is able to cross the phospholipid bilayer directly.
b)
i) Molecule T
ii) Rough endoplasmic reticulum [ribosome may be accepted as an alternative, but is less correct].
iii) tRNAs, via their own anticodons, bind to complementary codons of the mRNA situated in the ribosome. The tRNAs bring amino acids to the ribosome, which joins the amino acids together in a condensation reaction. The process is repeated until a stop codon is reached, ejecting the nascent polypeptide from the ribosome. [this question is challenging and I am unclear on whether they expect students to discuss translation or the specifics of the chemistry that leads to polypeptide formation. I have chosen the former, because I believe there is not enough VCE-relevant information to justify 3 marks for the latter].
c) Expression of a gene generates pre-mRNA. This molecule is then subjected to post-transcriptional modification, which includes splicing of introns from the RNA. In some cases, it is possible to splice different sections of the pre-mRNA, in a process called alternate splicing. As the name implies, this leads to the generation of alternate forms of mRNA from the pre-mRNA, each with different nucleotide sequences, which upon translation, will result in the generation of polypeptides with different amino acid sequences.
Post by: PhoenixxFire on November 03, 2017, 08:19:51 pm
I said that the greater concentration of phenolic acid helped to activate genes which then produced a greater amount of protein products which were toxic to the caterpillars, so therefore they fed on mature leaves as they weren't so toxic.I thought about that but the image showed one caterpillar - so if it died it could not eat the other leaf.
Post by: vox nihili on November 03, 2017, 08:21:42 pm
answers for section b will be up later tonight hopefully
They will dribble out this evening. Once they're done I'll combine all the answers into one document :)
Post by: ardria on November 03, 2017, 08:22:25 pm
Sine kindly estimated ~114/120 earlier in the year based on previous exams' scaling reports, but I'm wondering if this could be updated now that the exam is all done.
Post by: Jo Kamm on November 03, 2017, 08:40:39 pm
They gave us a 6 mark question that was about mass extinction of Australian MegaFauna. we had to read an excerpt of an article (something from The Conversation) and identify 3 points that provided evidence against the rapid extinction theory and why. It felt like an English exam >:(
After all those immunity questions people were asking yesterday, the only short answer questions were on innate immunity.
What did people pick for MC Q40? I changed my mind last minute.
They gave us a 6 mark question that was about mass extinction of Australian MegaFauna. we had to read an excerpt of an article (something from The Conversation) and identify 3 points that provided evidence against the rapid extinction theory and why. It felt like an English exam >:(I chose B as we have no evidence for A, c or D
After all those immunity questions people were asking yesterday, the only short answer questions were on innate immunity.
What did people pick for MC Q40? I changed my mind last minute.
Post by: Jo Kamm on November 03, 2017, 08:46:51 pm
Post by: waterangel82 on November 03, 2017, 08:51:14 pm
I thought about that but the image showed one caterpillar - so if it died it could not eat the other leaf.
I don't really know. But if something was more toxic, wouldn't there still be a possibility for a caterpillar to survive but in a poorer condition (like if a human was exposed to a toxin, there are non-fatal symptoms like diarrhoea and anaemia).
Post by: Spooky on November 03, 2017, 08:52:54 pm
Post by: Pandable on November 03, 2017, 08:55:38 pm
I put adaptive immunity for SA q 4 d i since wouldn't "venom inhibitors" be specific?Yes Venom inhibitors are specific immunity but it is also innate as the venom inhibitors do not actually trigger t helper cells so your body it self is not adapting
Post by: PhoenixxFire on November 03, 2017, 08:58:22 pm
I don't really know. But if something was more toxic, wouldn't there still be a possibility for a caterpillar to survive but in a poorer condition (like if a human was exposed to a toxin, there are non-fatal symptoms like diarrhoea and anaemia).Yeah thats why I wasn't sure, but I figured even if it was non-fatal it wouldn't start soon enough for the caterpiller to realise the pain was due to the leaf (thanks psychology!)
Post by: vox nihili on November 03, 2017, 08:59:37 pm
2)
a) Many plants coat themselves in wax to prevent access to the plant tissue by pathogens.
b) To serve as a negative control
c) In runner A, 0.6 of the leaf surface area of the young ramet was eaten; whereas, in runner B <0.3 was eaten. Representing a difference of approx. 0.3.
d) Phenolic acid leads to the production of a cytotoxic compound that is safe to the plants but makes the caterpillar ill.
Post by: vox nihili on November 03, 2017, 09:05:47 pm
3)
a) Rational drug design refers to the use of structural information about a drug target to inform the synthesis of a drug capable of binding that target.
b) It is able to bind the active site of HMG-CoA reductase.
c) Low levels of lovastatin will see many HMG-CoA reductase enzymes disinhibited. This will allow the enzyme to catalyse the synthesis of mevalonate, prompting the production of cholesterol.
I put adaptive immunity for SA q 4 d i since wouldn't "venom inhibitors" be specific?
I haven't read the question yet, but I suspect you're right. Anything that will inhibit a venom will be specific to that venom. It's by this way that you hear stories about old kings who used to take low levels of venom and thus become immune to snake bites. This is completely bioplausible.
Post by: PhoenixxFire on November 03, 2017, 09:08:42 pm
d) Phenolic acid leads to the production of a cytotoxic compound that is safe to the plants but makes the caterpillar ill.Do you think VCAA would accept that it would make a protein that tastes bad? My psychology is coming in here but unless it was immediately ill it wouldn't realise it feeling ill was due to the plant it just ate.
Post by: Pandable on November 03, 2017, 09:11:25 pm
Do you think VCAA would accept that it would make a protein that tastes bad? My psychology is coming in here but unless it was immediately ill it wouldn't realise it feeling ill was due to the plant it just ate.I honestly think it was because it tasted bad illness seems like a slow repellent, taste or smell changes is what i would assume to be the answer
Post by: vox nihili on November 03, 2017, 09:20:15 pm
4)
a)
i) Free from microorganisms.
ii) Cleaning of equipment with steam.
Strict procedures for “scrubbing in” to sterile fields.
[there are plenty of potential answers here]
b) The variable region of an antibody, to which the light and heavy chain both contribute components, is specific to a molecular motif on the antibody target. Thanks to this specificity, the antibody is thus able to bind to its target, thereby targeting it for phagocytosis, neutralising the pathogen or triggering agglutination of the pathogen.
[not sure how necessary the roles of antibodies are in the answer to this question. Again, a little vague. The most important information here is an understanding of the antibody’s specificity to their target]
c) Natural passive immunity. By acquiring antibodies from its mother’s milk, the joey gains a level of protection from those pathogens against which the mother has been immunised.
d)
i) Innate immune system.
ii) Venom inhibitors prevent pathogenic toxins from taking effect in the wallaby.
e) They hope to find a way to make these potential new antibiotics viable and safe for use in humans and other animals.
I haven't read the question yet, but I suspect you're right. Anything that will inhibit a venom will be specific to that venom. It's by this way that you hear stories about old kings who used to take low levels of venom and thus become immune to snake bites. This is completely bioplausible.
Scratch that. Having done the question, these are molecules that have evolved over a long period of time to nullify the effects of pathogenic venoms to which wallabies have been exposed to over the ages. Grouped with the others, they are clearly innate.
Do you think VCAA would accept that it would make a protein that tastes bad? My psychology is coming in here but unless it was immediately ill it wouldn't realise it feeling ill was due to the plant it just ate.
Yes, I think they would accept either answer. Ill, dead or bad taste, all of these things might work. It could even change the colour of the clover. All reasonable answers.
Post by: Pandable on November 03, 2017, 09:25:31 pm
Post by: TRA0023 on November 03, 2017, 09:27:18 pm
Post by: Jmano1420 on November 03, 2017, 09:29:01 pm
Post by: waterangel82 on November 03, 2017, 09:30:03 pm
Will be back to it after 10 with completed answers hopefully around 10.30-11.
4)
a)
i) Free from microorganisms.
ii) Cleaning of equipment with steam.
Strict procedures for “scrubbing in” to sterile fields.
[there are plenty of potential answers here]
b) The variable region of an antibody, to which the light and heavy chain both contribute components, is specific to a molecular motif on the antibody target. Thanks to this specificity, the antibody is thus able to bind to its target, thereby targeting it for phagocytosis, neutralising the pathogen or triggering agglutination of the pathogen.
[not sure how necessary the roles of antibodies are in the answer to this question. Again, a little vague. The most important information here is an understanding of the antibody’s specificity to their target]
c) Natural passive immunity. By acquiring antibodies from its mother’s milk, the joey gains a level of protection from those pathogens against which the mother has been immunised.
d)
i) Innate immune system.
ii) Venom inhibitors prevent pathogenic toxins from taking effect in the wallaby.
e) They hope to find a way to make these potential new antibiotics viable and safe for use in humans and other animals.
Scratch that. Having done the question, these are molecules that have evolved over a long period of time to nullify the effects of pathogenic venoms to which wallabies have been exposed to over the ages. Grouped with the others, they are clearly innate.
Yes, I think they would accept either answer. Ill, dead or bad taste, all of these things might work. It could even change the colour of the clover. All reasonable answers.
Hi,
would 'free from presence of pathogens be okay for 4.) a.ii?
And for 4e, is it alright if you said that the scientists hoped that treating humans with these peptides would help them to recover from bacterial infection much faster than those being treated with antibiotics?
Post by: Pandable on November 03, 2017, 09:30:50 pm
Post by: Sine on November 03, 2017, 09:31:17 pm
Would they accept non-specific immunity instead or innate cause I couldn’t remember what it was called?i don't think so non-specific is a property of the innate immune system
Post by: vox nihili on November 03, 2017, 09:34:18 pm
Hi,
would 'free from presence of pathogens be okay for 4.) a.ii?
And for 4e, is it alright if you said that the scientists hoped that treating humans with these peptides would help them to recover from bacterial infection much faster than those being treated with antibiotics?
It's technically not correct to say that sterile=free from pathogens, but I'd be surprised if the VCE course made this distinction. Aseptic means free from pathogens, sterile means free from all microorganisms. I suspect they'll award marks to both, irrespective of the truth of it.
Yes, I think that would be ok.
Would hygienic be correct for sterile?
Unlikely, sorry
Post by: biosista on November 03, 2017, 09:34:51 pm
Will be back to it after 10 with completed answers hopefully around 10.30-11.
4)
a)
i) Free from microorganisms.
ii) Cleaning of equipment with steam.
Strict procedures for “scrubbing in” to sterile fields.
[there are plenty of potential answers here]
b) The variable region of an antibody, to which the light and heavy chain both contribute components, is specific to a molecular motif on the antibody target. Thanks to this specificity, the antibody is thus able to bind to its target, thereby targeting it for phagocytosis, neutralising the pathogen or triggering agglutination of the pathogen.
[not sure how necessary the roles of antibodies are in the answer to this question. Again, a little vague. The most important information here is an understanding of the antibody’s specificity to their target]
c) Natural passive immunity. By acquiring antibodies from its mother’s milk, the joey gains a level of protection from those pathogens against which the mother has been immunised.
d)
i) Innate immune system.
ii) Venom inhibitors prevent pathogenic toxins from taking effect in the wallaby.
e) They hope to find a way to make these potential new antibiotics viable and safe for use in humans and other animals.
Scratch that. Having done the question, these are molecules that have evolved over a long period of time to nullify the effects of pathogenic venoms to which wallabies have been exposed to over the ages. Grouped with the others, they are clearly innate.
Yes, I think they would accept either answer. Ill, dead or bad taste, all of these things might work. It could even change the colour of the clover. All reasonable answers.
would the inflammatory response have been appropriate for the question about which part of the immune system that the chemicals are produced?
Post by: zenith101 on November 03, 2017, 09:45:04 pm
Post by: Chchchh on November 03, 2017, 09:48:54 pm
Post by: casematta on November 03, 2017, 09:51:04 pm
Q34: Isn't Taq polymerase used in PCR? Therefore C would be the most correct answerTaq polymerase is a type of DNA polymerase. Hence this is the most correct answer.
Post by: pap0007 on November 03, 2017, 09:51:15 pm
Post by: biosista on November 03, 2017, 09:53:12 pm
Doea anyone have the copy of the whole vcaa exam for biology?https://atarnotes.com/forum/index.php?topic=174920.msg1000351#msg1000351
Post by: James Holgate on November 03, 2017, 10:25:49 pm
Also, why was multiple choice q19 answer D correct over B? I was tossing between the two as the seemed similar
B was decreased rate of apoptosis in the surrounding normal cells
D was impaired signalling from death receptors located on the membrane of cancer cells
Dont both lead to cancer? Cheers
Post by: vox nihili on November 03, 2017, 10:26:29 pm
a) Gene flow refers to the exchange of alleles between different populations of the same species. It is unlikely to occur between these populations, due to the extent of the geographical separation between them and this species’ propensity not to stray far from the extents of its population.
b) The rufous bristlebird is at risk of extinction because its small population provides for very little genetic variation. This means that if there is a significant shift in the environment in which these populations lie, there may not be members of the population with the requisite traits to withstand the change.
6)
a) DNA fragments from two separate species are mixed and subsequently heated to separate the strands. They are then cooled, with the strands allowed to anneal to each other. Once again, the strands are heated and the temperature at which the DNA denatures is noted. This temperature is termed the melting temperature and is used in the determination of species’ relatedness.
b) Melting temperature correlates with the degree of relatedness between species, as higher temperatures imply a higher degree of sequence similarity of the DNA samples. Species that are more closely related are likely to have evolved from more proximate ancestors than those less closely related.
7)
a) Narrow waist. Large hip, knee and ankle joints. [This question will be controversial. Traditionally, the delineation between Australopithecus and Homo has been based on two things: tool-making and evidence of so-called competent bipedalism. There is no skeletal evidence of tool-making. I have provided evidence of “competent” bipedalism; however, expecting a VCE student to know these is fairly unreasonable. There is also the fact that there are not really a set of internationally accepted criteria about how to delineate these genera. Cranial capacity should not be referred to in this answer; early Homo species had small brains].
b) If H.naledi had arisen 900K years ago, it would have done so at a point at which H.erectus already existed. Given the striking similarities between H.erectus and humans, as well as the abundance of evidence that humans evolved from them, this would make it difficult to make a case for H.naledi as being a step between Australopithecus and humans, because it would by necessity invalidate the case for H.erectus.
8)
a) A genetic screening programme allows for early diagnosis and thus early intervention for babies with genetic diseases, in the hope of securing a better clinical outcome for these infants.
b) Privacy: babies’ genetic data is, by necessity, collected and stored as part of the programme. Parents: may be reluctant to conceive again due to risk of disease.
9)
a) A means of transferring genetic material from one species to another.
b)
i) Restriction enzymes cut plasmids, thus revealing sticky ends at either end of the open plasmid. They are also used to prepare a segment of DNA for insertion, which will have sticky ends complementary to those of the plasmid. This allows for annealing and subsequent ligation of the inserted DNA and the plasmid.
ii) The human gene should be within the tcl gene. The rest of the diagram should be as above.
c) All of the bacteria are spread onto a petri dish enriched with ampicillin. Those bacteria that have taken up the plasmid will gain an ampicillin resistance gene (amp) and, as such, will be able to grow on the petri dish. Those bacteria that failed to take up the plasmid will be eliminated by the ampicillin; thus all bacteria growing on the dish will have the plasmid.
10)
a) The rapid extinction model proposes that many species became extinct in a short space of time, suggesting that a critical event or a series of critical events precipitated this extinction event. Two such references are made in the text. Evidence that the extinction happened soon after humans arrived in Australia provides a potential example of the kind of major change needed to precipitate an extinction. Another possibility referred to in the text is a rapid change in climate, which may have precipitated the extinction event.
b) Table in pdf answers.
Post by: IsabellaBrown on November 03, 2017, 11:21:06 pm
Post by: jaronmak on November 03, 2017, 11:45:07 pm
Also, why was multiple choice q19 answer D correct over B? I was tossing between the two as the seemed similarI chose B as well, but I think it's wrong because there would be a decreased rate of apoptosis in the cancer cells, not the normal cells
B was decreased rate of apoptosis in the surrounding normal cells
D was impaired signalling from death receptors located on the membrane of cancer cells
Dont both lead to cancer? Cheers
Post by: James Holgate on November 03, 2017, 11:49:24 pm
b) Table in pdf answers.
Am I missing where the pdf answers are?—or are they just not uploaded yet, sorry
Post by: vox nihili on November 04, 2017, 12:04:48 am
Should we also mention the use of tetracycline to test samples of colonies of the bacteria resistant to ampicillin, to differentiate between bacteria that took up a plasmid which has the successfully inserted human gene and bacteria that did not?
Hmmm, very true point! I'll amend the answer. Have to admit that I didn't read the question in its entirety.
I chose B as well, but I think it's wrong because there would be a decreased rate of apoptosis in the cancer cells, not the normal cells
Why would you kill perfectly normal surrounding cells?
Am I missing where the pdf answers are?—or are they just not uploaded yet, sorry
They're one minute off—sorry!
Post by: vox nihili on November 04, 2017, 12:08:15 am
Post by: Sine on November 04, 2017, 12:14:27 am
Post by: Bri MT on November 04, 2017, 08:19:25 am
so happy i did bio before research questions beyond experimental design was a thing ;D ;DIn my exam people were panicking because 4 marks were allocated instead of the usual 3, and variables were controlled in the stem of the q. Doesn't seem as much of a big difference now
It's going to be interesting to see how schools adapt to teach their students how to answer these qs, and what these questions & reactions look like next year
Post by: angus4 on November 04, 2017, 08:35:14 am
Post by: Zaljc on November 04, 2017, 08:42:07 am
What do people think the A+ cut off will be for this year?
Post by: skybluemaniac on November 04, 2017, 10:07:55 am
However, the one gene multiple proteins question was tough! I did that in the 2015 question and was one of the few that got it right. I don't think it's fair to expect students to know that alternative exon shuffling leads to different proteins...
Post by: Joseph41 on November 04, 2017, 10:29:30 am
Post by: vox nihili on November 04, 2017, 10:30:26 am
Could I say "reset levels of Oxygen and Carbon dioxide to what they were on the first day, to ensure validity and repeatibility" for the control measures cockroach question?
It’s not greatest answer because those levels should probably correct on their own, but you might just get away with that one!
The general consensus seems that everyone found it super hard and I was hyped to see the exam. In my opnion I would say it's a little trickier than usual, but not overly tricky. The megafauna questions requires careful reading though..definitely an interesting question.
However, the one gene multiple proteins question was tough! I did that in the 2015 question and was one of the few that got it right. I don't think it's fair to expect students to know that alternative exon shuffling leads to different proteins...
I agree. I don’t think there was a lot to make anyone worried about this exam.
The last experimental design question was extremely challenging, particularly when they asked students to make conclusions.
The 2 mark question on the skeletal delineation between Homo and Australopithecus was also unreasonable.
Otherwise, most of the exam was fairly straightforward, especially the MCQ
Post by: smamsmo22 on November 04, 2017, 11:21:04 am
Thanks
Post by: casematta on November 04, 2017, 11:26:58 am
Hmmm, very true point! I'll amend the answer. Have to admit that I didn't read the question in its entirety. !
The question implies that the plasmids used are all recombinant, so the tetracycline would not have to be used in your last step. I think that instead they wanted students to see that the gene was broken and so tetracycline could not be used as both transformed and normal bacteria would both die from it. Thoughts?
Post by: Domek on November 04, 2017, 11:31:17 am
1. So for the question about describing the chemical reaction that occurs in the joining of amino acids (1.b)iii)), I described the process of condensation polymerisation. I talked about how the hydroxide from the carboxyl group joins with the hydrogen from the amine group of the other amino acids, to form water which is released, resulting in a peptide bond between the amino acids. It was on the study design and the question did ask to describe the 'chemical reaction'. Did anyone else do that as well and would I get some marks?
2. I said innate immunity instead of innate immune system for question 4.d)i). Is that acceptable?
3. For 7.b) would it be sufficient to say that 900 000 years ago (the age of the H. naledi fossil) Australopithecus was extinct, so it could not have been the missing link?
4. One of the ethical considerations I mentioned was discrimination of the individuals testing positive by insurance companies, especially later in their life. Is this relevant?
5. Approx. how many marks would I lose if I didn't mention ampicillin and tetracylin in my answer for 9. c)? I just kind of generally talked about an 'antibiotic' because I didn't read the question properly :I
6. For 10. f) one of controlled variables was how the temperature was kept at 30 degrees for 10 minutes and then decreased for 20 minutes, so the amount of time for each temperature would not have been the same. So the oxygen levels and carbon dioxide levels would have been different at for example 10 degrees than if it had been at that temperature for 10 minutes. What do you think?
Thanks a bunch for the solutions! They're really helpful! :D
Post by: waterangel82 on November 04, 2017, 11:40:56 am
I have checked Vox's answers, but I'm not sure if what I said could also potentially be okay.
1.) For SA 4e, I said that the scientists hope to find that the humans who took peptides would recover from bacterial infections much more quickly compared to those who took antibiotics.
2.) For SA 7a, I said that genus Homo would generally have a (much) shorter arm-to-leg ratio compared to Australopithecus.
3.) For SA 7b, I said that because the H.naledi appeared less that 1 mya, this means that the existed at a time when H. erectus was already around. Also, I mention how H. habilis and H. ergaster existed earlier than H.naledi, so H. naledi would not be the link. Is this sufficient for 1 mark?
4.) For SA 10a, I did quote some references in the text, but I also kind of explained more because it was 3 marks. I said something like because of the fact that the environment changed so much from the burning and excessive hunting (different selection pressures), the megafauna did not possess the favourable phenotypes to survive and pass down to offspring, so rapid extinction occurred. Would this be acceptable?
5.) For SA 10b, I said some very general justifications, such as that the coexistence of First Australians and megafauna for 17000 years suggests that perhaps the extinction of these species were not as rapid as thought. Would this be sufficient?
6.) For SA 11e, I said that recording for 4 minutes would allow better precision and accuracy of results.
7.) For SA 11f, would controlling the temperature of the heat lamp be valid? Also, would it also make sense to say that the same type of food was given (because some foods can speed up rate of cellular respiration)?
8.) For SA 11gii, would it be valid to conclude that 'as temperature decreases, the rate of aerobic cellular respiration in the cockroach decreases' and then give the evidence to back up?
Thanks!
Post by: vox nihili on November 04, 2017, 11:43:53 am
The question implies that the plasmids used are all recombinant, so the tetracycline would not have to be used in your last step. I think that instead they wanted students to see that the gene was broken and so tetracycline could not be used as both transformed and normal bacteria would both die from it. Thoughts?
They ask you how they can identify which ones took up the plasmid with the gene in it, so you’d have to talk about the tetracycline.
If you read my answer in the pdf, you’ll see an explanation of how they use the tetracycline.
Hi,
1. So for the question about describing the chemical reaction that occurs in the joining of amino acids (1.b)iii)), I described the process of condensation polymerisation. I talked about how the hydroxide from the carboxyl group joins with the hydrogen from the amine group of the other amino acids, to form water which is released, resulting in a peptide bond between the amino acids. It was on the study design and the question did ask to describe the 'chemical reaction'. Did anyone else do that as well and would I get some marks?
2. I said innate immunity instead of innate immune system for question 4.d)i). Is that acceptable?
3. For 7.b) would it be sufficient to say that 900 000 years ago (the age of the H. naledi fossil) Australopithecus was extinct, so it could not have been the missing link?
4. One of the ethical considerations I mentioned was discrimination of the individuals testing positive by insurance companies, especially later in their life. Is this relevant?
5. Approx. how many marks would I lose if I didn't mention ampicillin and tetracylin in my answer for 9. c)? I just kind of generally talked about an 'antibiotic' because I didn't read the question properly :I
6. For 10. f) one of controlled variables was how the temperature was kept at 30 degrees for 10 minutes and then decreased for 20 minutes, so the amount of time for each temperature would not have been the same. So the oxygen levels and carbon dioxide levels would have been different at for example 10 degrees than if it had been at that temperature for 10 minutes. What do you think?
Thanks a bunch for the solutions! They're really helpful! :D
Will answer this in a tic :)
Post by: landem on November 04, 2017, 11:44:34 am
It was unlike any exam I’ve done before and although I felt I had all the background knowledge that I needed, I found some questions really difficult when it seemed like writing was being assessed more than biology content.
The megafauna question seemed like a waste of marks when there was no SA on photosynthesis, speciation, natural selection, fossils, signal transduction, allergic or immune responses etc
Post by: casematta on November 04, 2017, 11:46:51 am
Post by: bayliejade99 on November 04, 2017, 12:14:12 pm
Post by: vox nihili on November 04, 2017, 12:32:48 pm
Hi Guys,
I have checked Vox's answers, but I'm not sure if what I said could also potentially be okay.
1.) For SA 4e, I said that the scientists hope to find that the humans who took peptides would recover from bacterial infections much more quickly compared to those who took antibiotics.
2.) For SA 7a, I said that genus Homo would generally have a (much) shorter arm-to-leg ratio compared to Australopithecus.
3.) For SA 7b, I said that because the H.naledi appeared less that 1 mya, this means that the existed at a time when H. erectus was already around. Also, I mention how H. habilis and H. ergaster existed earlier than H.naledi, so H. naledi would not be the link. Is this sufficient for 1 mark?
4.) For SA 10a, I did quote some references in the text, but I also kind of explained more because it was 3 marks. I said something like because of the fact that the environment changed so much from the burning and excessive hunting (different selection pressures), the megafauna did not possess the favourable phenotypes to survive and pass down to offspring, so rapid extinction occurred. Would this be acceptable?
5.) For SA 10b, I said some very general justifications, such as that the coexistence of First Australians and megafauna for 17000 years suggests that perhaps the extinction of these species were not as rapid as thought. Would this be sufficient?
6.) For SA 11e, I said that recording for 4 minutes would allow better precision and accuracy of results.
7.) For SA 11f, would controlling the temperature of the heat lamp be valid? Also, would it also make sense to say that the same type of food was given (because some foods can speed up rate of cellular respiration)?
8.) For SA 11gii, would it be valid to conclude that 'as temperature decreases, the rate of aerobic cellular respiration in the cockroach decreases' and then give the evidence to back up?
Thanks!
1. Potentially ok.
2. Yes, that's fine
3. That sounds reasonable. The idea that there are lots of other species that appear to predate H.naledi really works against it being the link; you could go with that logic too.
4. That's fine but it was unnecessary. You only need to answer what you're asked.
5. I think that's fine.
6. They might accept this, but it doesn't really demonstrate that you know what you're talking about, although yuo're technically correct. I think accuracy is the more important factor here.
7. No, it wouldn't be. He uses the same protocol each time with the same lamp and we can see from the results that he graphed against the temperature anyway, so it was already controlled. Food is fine.
8. No, this is not what the graph shows. The rate of respiration is the same for every temperature below 30, it doesn't decrease with temperature according to those graphs.
The megafauna question seemed like a waste of marks when there was no SA on photosynthesis, speciation, natural selection, fossils, signal transduction, allergic or immune responses etc
There were some questions on some of these topics. The megafauna question was really an application question about natural selection. There were multiple questions on the SAQ that required knowledge of fossils, such as the megafauna and the H.naledi question. I agree that to some extent the immune system seemed fairly undersubscribed in the SAQ. This always happens with exams though, they can't ask about everything!
Also, for the question about rational drug design, for two marks it is necessary to include that the drug will prevent the natural action of the molecule which it binds to from occurring. Have seen this in previous exams- definitely worth adding.
No, this is unnecessary.
is aerobic cellular respiration OK to say for Q11a or does it have to be cellular respiration
That's perfectly fine :)
Post by: waterangel82 on November 04, 2017, 01:35:57 pm
1. Potentially ok.
2. Yes, that's fine
3. That sounds reasonable. The idea that there are lots of other species that appear to predate H.naledi really works against it being the link; you could go with that logic too.
4. That's fine but it was unnecessary. You only need to answer what you're asked.
5. I think that's fine.
6. They might accept this, but it doesn't really demonstrate that you know what you're talking about, although yuo're technically correct. I think accuracy is the more important factor here.
7. No, it wouldn't be. He uses the same protocol each time with the same lamp and we can see from the results that he graphed against the temperature anyway, so it was already controlled. Food is fine.
8. No, this is not what the graph shows. The rate of respiration is the same for every temperature below 30, it doesn't decrease with temperature according to those graphs.
There were some questions on some of these topics. The megafauna question was really an application question about natural selection. There were multiple questions on the SAQ that required knowledge of fossils, such as the megafauna and the H.naledi question. I agree that to some extent the immune system seemed fairly undersubscribed in the SAQ. This always happens with exams though, they can't ask about everything!
No, this is unnecessary.
That's perfectly fine :)
Thank you :). So for 11gii, would I still be able to receive 2 marks if I mentioned that the rate of consumption/production between 10-30 minutes (and give specific figures) was slower than the rate of consumption/production between 0-10 mins (and give specific figures)?
Post by: ShyamChandak on November 04, 2017, 01:50:08 pm
Post by: omgvce on November 04, 2017, 01:59:04 pm
1. Potentially ok.
2. Yes, that's fine
3. That sounds reasonable. The idea that there are lots of other species that appear to predate H.naledi really works against it being the link; you could go with that logic too.
4. That's fine but it was unnecessary. You only need to answer what you're asked.
5. I think that's fine.
6. They might accept this, but it doesn't really demonstrate that you know what you're talking about, although yuo're technically correct. I think accuracy is the more important factor here.
7. No, it wouldn't be. He uses the same protocol each time with the same lamp and we can see from the results that he graphed against the temperature anyway, so it was already controlled. Food is fine.
8. No, this is not what the graph shows. The rate of respiration is the same for every temperature below 30, it doesn't decrease with temperature according to those graphs.
There were some questions on some of these topics. The megafauna question was really an application question about natural selection. There were multiple questions on the SAQ that required knowledge of fossils, such as the megafauna and the H.naledi question. I agree that to some extent the immune system seemed fairly undersubscribed in the SAQ. This always happens with exams though, they can't ask about everything!
No, this is unnecessary.
That's perfectly fine :)
Hi vox,
Could you please explain how for q11gii, the graphs don't show a slower rate of respiration as temperature falls?
As temperatures fell below 30 degrees, the rate of oxygen intake reduced and the rate of carbon dioxide production reduced as well, shown by less slopey gradients. Does this not imply a slower rate of respiration?
Thank you :)
Post by: vox nihili on November 04, 2017, 02:17:29 pm
Thank you :). So for 11gii, would I still be able to receive 2 marks if I mentioned that the rate of consumption/production between 10-30 minutes (and give specific figures) was slower than the rate of consumption/production between 0-10 mins (and give specific figures)?
Yes I think so. That sounds pretty reasonable.
Hi vox,
Could you please explain how for q11gii, the graphs don't show a slower rate of respiration as temperature falls?
As temperatures fell below 30 degrees, the rate of oxygen intake reduced and the rate of carbon dioxide production reduced as well, shown by less slopey gradients. Does this not imply a slower rate of respiration?
Thank you :)
Hey there!
To be perfectly honest, I thought this was a frighteningly difficult question, to the extent that I wonder whether VCAA will produce the right answer themselves.
If you look carefully at the graphs, on the x axis we have time and on the y-axis we have the % amount of oxygen or carbon dioxide. The rate of cellular respiration is thus given by the slope/gradient of the graph, not the y-value of the graph. A rate is a change in quantity over time...we have a quantity on the y-axis and we have a time on the x axis, therefore it's the gradient that gives us the rate in this case.
Now iwith that in ind, if we look at the graph we can see that gradient of the graph is quite steep as the temperature is kept constant at 30 degrees, but when the temperature starts to fall, the gradient falls. Critically, the gradient doesn't change as the temperature falls. This indicates that the rate of respiration below 30°C in this experiment is kept the same. So whether it's 25°C or 10°C there's no difference in the rate.
Another reasonable conclusion that could be made on the basis of those data is that the rate of respiration is highest at 30°C and lower at lower temperatures. If you say that the rate of respiration correlates with temperature though, you would be wrong. The data don't demonstrate this.
The challenge of this experiment was ditching your preconceived notions about what should happen in the system and actually just focus in on what the results of the experiment tell us. The reality is that the experiment probably wasn't that good, hence the unexpected results.
Post by: omgvce on November 04, 2017, 02:36:43 pm
Yes I think so. That sounds pretty reasonable.
Hey there!
To be perfectly honest, I thought this was a frighteningly difficult question, to the extent that I wonder whether VCAA will produce the right answer themselves.
If you look carefully at the graphs, on the x axis we have time and on the y-axis we have the % amount of oxygen or carbon dioxide. The rate of cellular respiration is thus given by the slope/gradient of the graph, not the y-value of the graph. A rate is a change in quantity over time...we have a quantity on the y-axis and we have a time on the x axis, therefore it's the gradient that gives us the rate in this case.
Now iwith that in ind, if we look at the graph we can see that gradient of the graph is quite steep as the temperature is kept constant at 30 degrees, but when the temperature starts to fall, the gradient falls. Critically, the gradient doesn't change as the temperature falls. This indicates that the rate of respiration below 30°C in this experiment is kept the same. So whether it's 25°C or 10°C there's no difference in the rate.
Another reasonable conclusion that could be made on the basis of those data is that the rate of respiration is highest at 30°C and lower at lower temperatures. If you say that the rate of respiration correlates with temperature though, you would be wrong. The data don't demonstrate this.
The challenge of this experiment was ditching your preconceived notions about what should happen in the system and actually just focus in on what the results of the experiment tell us. The reality is that the experiment probably wasn't that good, hence the unexpected results.
Oh I get you! So the rate only decreased once from a higher rate to a fixed lower rate... rather than continually decreasing as temperature decreases.
Well now I really hope vcaa doesn't take that too seriously when marking :/
Thanks for your really quick reply! :)
Post by: vox nihili on November 04, 2017, 02:44:29 pm
Oh I get you! So the rate only decreased once from a higher rate to a fixed lower rate... rather than continually decreasing as temperature decreases.
Well now I really hope vcaa doesn't take that too seriously when marking :/
Thanks for your really quick reply! :)
That’s an excellent way to summarise the point.
The question is genuinely that tricky that I’m worried they might not even know that’s the right interpretation
Post by: PhoenixxFire on November 04, 2017, 03:23:36 pm
Anyone else feel pretty disappointed in how they (presumably) did? I feel like the concepts I spent extra time solidifying and all the techniques I really tried to develop from doing past exams and 2017 practice papers weren't reflected in my exam at all :( Not having a go at the exam or anything, I just generally feel quite disconcerted with that (and my own efforts) and wanted to know how other people found it (or any advice etc).I think the reason I really hated this exam was because I walked in expecting it to be like it has been previously. I understand them changing it but I'm annoyed that the sample exam did not refelect how the actual exam would be. The sample exam was typical of the last study design + an experimental design question, so that is what I expected. Not a 3+6 mark interpret the paragraph and 4 pages of experimental design...
Thanks
Post by: Sine on November 04, 2017, 03:28:34 pm
Post by: IsabellaBrown on November 04, 2017, 03:41:51 pm
The general consensus seems that everyone found it super hard and I was hyped to see the exam. In my opnion I would say it's a little trickier than usual, but not overly tricky. The megafauna questions requires careful reading though..definitely an interesting question.
However, the one gene multiple proteins question was tough! I did that in the 2015 question and was one of the few that got it right. I don't think it's fair to expect students to know that alternative exon shuffling leads to different proteins...
I found the alternative splicing question slightly easier to understand than the experimental design questions and the article analysis. I just wish they made the exam cover everything equally rather than just predominantly on experimental design.
Post by: PhoenixxFire on November 04, 2017, 04:10:00 pm
I found the alternative splicing question slightly easier to understand than the experimental design questions and the article analysis. I just wish they made the exam cover everything equally rather than just predominantly on experimental design.I found the alternate splicing fairly easy too. My teacher has talked about it and so has edrolo. I suspect next year the exam will be a bit more even - I had been told they over assess new content.
Post by: IsabellaBrown on November 04, 2017, 04:43:06 pm
I found the alternate splicing fairly easy too. My teacher has talked about it and so has edrolo. I suspect next year the exam will be a bit more even - I had been told they over assess new content.
I watched it on Edrolo too! Edrolo helped a lot. I must admit, when I read it I wasn't sure if alternative splicing would be correct but it was the only thing I could think of. Yes, that is what I think will happen too.
Post by: neenah on November 04, 2017, 06:38:51 pm
Question 1 SAQ below...others will come out slowly (I have exams coming up too! :) )Hey for the question about joining amino acids it said "chemical reaction" and I assumed it referred to a condensation reaction rather than the process of translation. Is my answer completely wrong?
Author comments in [brackets].
1)
a)
i) The arrow should point downwards from the extracellular environment to the intracellular environment and should cross the phospholipid component of the membrane.
ii) The concentration of the molecular is higher in the extracellular environment than in the intracellular; therefore, it will diffuse from the latter to the former down its concentration gradient. Owing to its hydrophobicity, it is able to cross the phospholipid bilayer directly.
b)
i) Molecule T
ii) Rough endoplasmic reticulum [ribosome may be accepted as an alternative, but is less correct].
iii) tRNAs, via their own anticodons, bind to complementary codons of the mRNA situated in the ribosome. The tRNAs bring amino acids to the ribosome, which joins the amino acids together in a condensation reaction. The process is repeated until a stop codon is reached, ejecting the nascent polypeptide from the ribosome. [this question is challenging and I am unclear on whether they expect students to discuss translation or the specifics of the chemistry that leads to polypeptide formation. I have chosen the former, because I believe there is not enough VCE-relevant information to justify 3 marks for the latter].
c) Expression of a gene generates pre-mRNA. This molecule is then subjected to post-transcriptional modification, which includes splicing of introns from the RNA. In some cases, it is possible to splice different sections of the pre-mRNA, in a process called alternate splicing. As the name implies, this leads to the generation of alternate forms of mRNA from the pre-mRNA, each with different nucleotide sequences, which upon translation, will result in the generation of polypeptides with different amino acid sequences.
Post by: vox nihili on November 04, 2017, 06:54:57 pm
Hey for the question about joining amino acids it said "chemical reaction" and I assumed it referred to a condensation reaction rather than the process of translation. Is my answer completely wrong?
I’m not sure to be honest. In my answers I think I mentioned that I wasn’t sure if they were after that or translation. The question was a little vague and I couldn’t understand how you could get 3 marks out of condensation polymerisation.
Post by: vox nihili on November 04, 2017, 06:55:28 pm
Hey for the question about joining amino acids it said "chemical reaction" and I assumed it referred to a condensation reaction rather than the process of translation. Is my answer completely wrong?
I’m not sure to be honest. In my answers I think I mentioned that I wasn’t sure if they were after that or translation. The question was a little vague and I couldn’t understand how you could get 3 marks out of condensation polymerisation.
Post by: neenah on November 04, 2017, 07:00:02 pm
I’m not sure to be honest. In my answers I think I mentioned that I wasn’t sure if they were after that or translation. The question was a little vague and I couldn’t understand how you could get 3 marks out of condensation polymerisation.maybe a mark for stating how it occurs, a mark for the name of the reaction, product and the bond, and a mark for saying water is a by product? Idk I was thinking about writing translation but the whole "chemical reaction" thing put me off.
Post by: PhoenixxFire on November 04, 2017, 07:00:35 pm
I’m not sure to be honest. In my answers I think I mentioned that I wasn’t sure if they were after that or translation. The question was a little vague and I couldn’t understand how you could get 3 marks out of condensation polymerisation.It was mentioned in detail in the SD this year. I wrote that a OH was lost from the carboxyl group, a H from the amino group, that these formed a water molecule and a peptide bind was formed.
Post by: IsabellaBrown on November 04, 2017, 07:09:57 pm
It was mentioned in detail in the SD this year. I wrote that a OH was lost from the carboxyl group, a H from the amino group, that these formed a water molecule and a peptide bind was formed.
Yeah I wrote that too, but I linked in that this occurs during translation at the end.
Post by: IsabellaBrown on November 04, 2017, 07:12:35 pm
Post by: vox nihili on November 04, 2017, 07:18:39 pm
It was mentioned in detail in the SD this year. I wrote that a OH was lost from the carboxyl group, a H from the amino group, that these formed a water molecule and a peptide bind was formed.
Yeah I wrote that too, but I linked in that this occurs during translation at the end.
It sounds like that would be reasonable. As I said, I was unsure was to whether they expected to hear the detail of the reaction. You've convinced me that this is probably the case. I'll amend the answers to reflect this, with a statement about the possibility that they could be after translation.
I wrote ribosome though instead of the rough endoplasmic reticulum because technically protein synthesis can occur on a ribosome in the cytosol or on a ribosome in the rER, depending on where it is needed. Would ribosome still be accepted??
It depends on how harsh they want to be. It's a membrane protein, so we actually know that it was made in the rER rather than a free ribosome. I think the answer they take will come down to whether or not their exam is coming up too easy or too hard.
Post by: IsabellaBrown on November 04, 2017, 07:36:13 pm
Wait I'm confused, sorry! Why would it be on the rER? I thought that proteins that are needed within the cell are made at a ribosome in the cytosol and those that are exported are synthesised in the rER..? I'm probably wrong. I just remember reading it somewhere.
Post by: HubHub on November 05, 2017, 12:49:28 am
For question 7a) about structural features differentiating Australipithecus and Homo, do you think accessors may accept traditional trends in hominin development? I'd never looked at whole genus' in isolation so was very taken aback by this one. I wrote that features may include 1) a less pronounced brow bone than the latest Australopithecus species, and a more parabolic jaw shape than the jaw of the (latest) Australopithecus species. I don't know if these would scrape by..... :(
Post by: vox nihili on November 05, 2017, 08:03:58 am
Cool, thank you for the help! :)
Wait I'm confused, sorry! Why would it be on the rER? I thought that proteins that are needed within the cell are made at a ribosome in the cytosol and those that are exported are synthesised in the rER..? I'm probably wrong. I just remember reading it somewhere.
That’s partially true. Any protein that is exported or needed within an organelle is made in the rER.
Any protein that is needed within the cytoplasm or the nucleus is made by free ribosomes. There are a couple of sneaky exceptions to this but they wouldn’t expect you to know them.
The means by which the rER gets proteins out of the cell or into organelles is by vesicular transport, in a process that is basically exocytosis. If you think about how that works, the vesicle fuses with the membrane (be it of the organelle or the PM) and actually ends up becoming a part of that membrane.
So with membrane proteins, if you had a protein on the membrane of that vesicle, it would then become part of the plasma membrane.
Hi guys,
For question 7a) about structural features differentiating Australipithecus and Homo, do you think accessors may accept traditional trends in hominin development? I'd never looked at whole genus' in isolation so was very taken aback by this one. I wrote that features may include 1) a less pronounced brow bone than the latest Australopithecus species, and a more parabolic jaw shape than the jaw of the (latest) Australopithecus species. I don't know if these would scrape by..... :(
I’m not really sure what answers they’ll accept and how broad they’ll go. It sounded like they were looking for something specific, but I’ve never heard the details of what separates those two genera in VCE before. Indeed, when I did some research on this to try to find some clarity on this question I actually couldn’t really find anything. As I mentioned in my answers, there’s not a commonly agreed upon set of rules governing this so it’s hard to say what actually does separate those genera.
Post by: HubHub on November 05, 2017, 10:28:50 am
For question 11d) about the improvements do you think they would accept 1) make concentration of oxygen constant in the chamber before the cockroach was admitted? On the graph in the front page it shows a graph where there are small fluctuations in O2 concentration, so I said that if this wasn't controlled it may slightly skew the results because the results about O2 conc may be convoluted by the small variations in oxygen gas of the chamber but not necessarily due to the cockroaches cellular respiration.2) make temperature in the chamber constant prior to admitting the cockroach. I had the same line of reasoning, stating that if temperature was not controlled it could dwindle the accuracy and reliability of results because the temperature could flucuate within the experiment because the original temperature starting the results may not have been 30 degrees as recorded. Do these seem acceptable, everyones getting such diferent answers and this is a 4 mark..... :( I really cant afford to lose this whole section. What do you think?
Post by: vox nihili on November 05, 2017, 10:46:58 am
So do you reckon it would possible to get any marks if you just discussed translation and not condensation polymerisation - explained in reference with tRNA and mRNA and mentioned the formation of peptide bonds but no other biochemical details??
I’m not really sure. As you can see, we’ve had a bit of debate about it. I’m leaning towards no at this point, but we’ll have to wait and see.
Thanks vox nihili.
For question 11d) about the improvements do you think they would accept 1) make concentration of oxygen constant in the chamber before the cockroach was admitted? On the graph in the front page it shows a graph where there are small fluctuations in O2 concentration, so I said that if this wasn't controlled it may slightly skew the results because the results about O2 conc may be convoluted by the small variations in oxygen gas of the chamber but not necessarily due to the cockroaches cellular respiration.2) make temperature in the chamber constant prior to admitting the cockroach. I had the same line of reasoning, stating that if temperature was not controlled it could dwindle the accuracy and reliability of results because the temperature could flucuate within the experiment because the original temperature starting the results may not have been 30 degrees as recorded. Do these seem acceptable, everyones getting such diferent answers and this is a 4 mark..... :( I really cant afford to lose this whole section. What do you think?
The first sounds reasonable and as long as you provided a good justification should be fine.
You might have a bit of trouble with the second, as the experimental design implies that the temperate is already controlled in the chamber before the cockroach goes in.
Post by: vox nihili on November 05, 2017, 01:51:05 pm
Was there an error in question 18- the two patients were administered the hormone insulin. The Glucose levels of both were measured after that- in that case both should have responded in the same way? I think the question should have said " glucose levels were measured after administering glucose to both patients". This would have shown that Shani's levels stayed the same (due to the mutated insulin gene) and Eleni's levels dropped to active insulin.
The question states that the mutation is in the receptor for insulin, not the insulin gene itself.
Post by: Cloudy99 on November 05, 2017, 02:17:13 pm
I feel like i bombed the whole exam right now :((
Post by: Arif422 on November 05, 2017, 08:43:58 pm
Anyone else feel pretty disappointed in how they (presumably) did? I feel like the concepts I spent extra time solidifying and all the techniques I really tried to develop from doing past exams and 2017 practice papers weren't reflected in my exam at all :( Not having a go at the exam or anything, I just generally feel quite disconcerted with that (and my own efforts) and wanted to know how other people found it (or any advice etc).
Thanks
I'm glad someone else feels the same way. Honestly, as you said I'm not here to beat on the exam, I'm just disheartened.. as most of us probably are. We've all worked through the "new study design" with the initial 69 dot points, which was only later to be cut down to about 10. I mean, surely there could've been like three less long stimulus questions.. as we only had a certain amount of time to complete it all. And who would've known that we had to know where each restriction enzyme would cut. Ye, a year's worth of study only left me to dread my end performance :)
Post by: ardria on November 06, 2017, 01:23:55 am
For the question about the physical development of plants i wrote the development of galls, would this be wrong ?, and for the phenolic acid one i said it the young plants produced a chemial that detered the capterpillar from eating it leaving it to eat the mature one, :((
I feel like i bombed the whole exam right now :((
I also wrote formation of galls but I explained in probably excessive detail what that actually means and how galls do their job. It's definitely a physical defense!
Post by: IsabellaBrown on November 06, 2017, 07:38:32 pm
That’s partially true. Any protein that is exported or needed within an organelle is made in the rER.
Any protein that is needed within the cytoplasm or the nucleus is made by free ribosomes. There are a couple of sneaky exceptions to this but they wouldn’t expect you to know them.
The means by which the rER gets proteins out of the cell or into organelles is by vesicular transport, in a process that is basically exocytosis. If you think about how that works, the vesicle fuses with the membrane (be it of the organelle or the PM) and actually ends up becoming a part of that membrane.
So with membrane proteins, if you had a protein on the membrane of that vesicle, it would then become part of the plasma membrane.
Ohhhhhhh. Well. That makes a lot of sense. Thanks!!
Post by: IsabellaBrown on November 06, 2017, 07:42:29 pm
I'm glad someone else feels the same way. Honestly, as you said I'm not here to beat on the exam, I'm just disheartened.. as most of us probably are. We've all worked through the "new study design" with the initial 69 dot points, which was only later to be cut down to about 10. I mean, surely there could've been like three less long stimulus questions.. as we only had a certain amount of time to complete it all. And who would've known that we had to know where each restriction enzyme would cut. Ye, a year's worth of study only left me to dread my end performance :)
Same here. I can't believe I spent a whole year revising so much content that wasn't even on the exam.
Post by: IsabellaBrown on November 08, 2017, 06:11:43 pm
For the plasmids and antibiotics questions, would you get any marks if you didn't mention ampicillin or tetracycline?
Post by: PhoenixxFire on November 08, 2017, 06:32:17 pm
Hey guys,
For the plasmids and antibiotics questions, would you get any marks if you didn't mention ampicillin or tetracycline?
I doubt it, but it was worth 3 marks so I suppose it's possible.
For some strange reason I interpreted it as all the bacteria had taken up a plasmid and we had to figure out which had taken up a correct plasmid...so I said culture them individually, split them in half, dose half with tetra and whichever died, use the other half of that culture. All those that hadn't taken up any plasmid would die too though 🤦♀️🤦♀️🤦♀️🤦♀️ No marks for me 😰 I completely bombed the exam, now I gotta hope someone in my cohort did better (I'm rank one) or I'm well and truly screwed.
Post by: Ahmad_A_1999 on November 08, 2017, 07:40:40 pm
I doubt it, but it was worth 3 marks so I suppose it's possible.
For some strange reason I interpreted it as all the bacteria had taken up a plasmid and we had to figure out which had taken up a correct plasmid...so I said culture them individually, split them in half, dose half with tetra and whichever died, use the other half of that culture. All those that hadn't taken up any plasmid would die too though 🤦♀️🤦♀️🤦♀️🤦♀️ No marks for me 😰 I completely bombed the exam, now I gotta hope someone in my cohort did better (I'm rank one) or I'm well and truly screwed.
WHAT thats how I interpreted it to, :( omg why is it wrong
Post by: PhoenixxFire on November 08, 2017, 07:52:45 pm
WHAT thats how I interpreted it to, :( omg why is it wrongNot all the bacteria took up any plasmid. So you have to give them amp to kill bacteria without a plasmid then do the rest. Good to know I'm not the only one. For next year I need to improve my reading 😂 But if I'd read them all really well, I would have run out of time. (I used my extra few minutes to badly reread the last MC and change my answer...to another wrong answer.)
Post by: Ahmad_A_1999 on November 08, 2017, 07:56:30 pm
Not all the bacteria took up any plasmid. So you have to give them amp to kill bacteria without a plasmid then do the rest. Good to know I'm not the only one. For next year I need to improve my reading 😂 But if I'd read them all really well, I would have run out of time. (I used my extra few minutes to badly reread the last MC and change my answer...to another wrong answer.)
:( I failed bio and I failed methods today hahaha fml
Post by: vox nihili on November 08, 2017, 09:42:35 pm
Also, regarding the plasmid question; don’t beat yourselves up for it. It was a stunningly hard question for VCE. Easy for anyone who’s used that technique, but otherwise extremely challenging. It won’t have been well answered.
Post by: ATARNOTES321 on November 09, 2017, 11:22:44 pm
Hopefully this makes sense!
Thanks in advance :)
Post by: HubHub on November 10, 2017, 10:45:10 am
For the experimental method section, why do you think they included that table showing the CO2 and O2 concentrations as well as temperature of the chamber without the cockroach? I used this table as the basis for my 11d) response, in the sense that the temperature and concentrations fluctuated in the chamber, thus, this may sway the reliability and validity of results for during the actual experiment, small changes (not due to the cockroaches respiration) in the chambers concentrations and temperature may impact results, however seemingly minute. Do you think this is why that table was included?
Post by: MLGityaJ^A on November 10, 2017, 10:37:03 pm
Hubhub, i think the table was just provided for question 11.c., not sure whether you could talk about it in 11.d. though
Mod edit: Posts merged. Please edit existing post instead of posting again.
Post by: vox nihili on November 11, 2017, 12:00:25 am
Hey guys, for Question 11.c. in the suggested solutions for the Biology Exam that were published here, it was said that Matthew measured the O2, CO2 concentration and temperature for four minutes to record more data and reduce the effect of random errors. However, wouldn't it be because he wanted to find out what point the values being recorded stopped changing? In the last three entries of Matthew's recordings, the values stayed the same. In addition, if Matthew wanted more precise values, wouldn't he simply take recording repeated times rather than just waiting for a period of time? My answer was that Matthew took four minutes to record so that he could obtain more ACCURATE values, rather than precise ones, by waiting long enough for the recordings taken every minute to stop changing, allowing for the true amount of O2, CO2 and level of temperature present in the container to be recorded.
Hubhub, i think the table was just provided for question 11.c., not sure whether you could talk about it in 11.d. though
Mod edit: Posts merged. Please edit existing post instead of posting again.
The sample solutions say nothing about precision. Reducing the effect of random error does make the results more accurate. Error means that the results are inherently inaccurate; therefore, by removing error we increase accuracy. The sample solutions perhaps should have mentioned accuracy directly.
Hi everyone,
For the experimental method section, why do you think they included that table showing the CO2 and O2 concentrations as well as temperature of the chamber without the cockroach? I used this table as the basis for my 11d) response, in the sense that the temperature and concentrations fluctuated in the chamber, thus, this may sway the reliability and validity of results for during the actual experiment, small changes (not due to the cockroaches respiration) in the chambers concentrations and temperature may impact results, however seemingly minute. Do you think this is why that table was included?
Hmmm I think the table just gives you a sense of how long it takes the chamber to heat up and actually shows you that at 30°C the CO2 and O2 are actually pretty constant. The table makes you feel more confident that the results he is taking are quite precise.
I'm not sure that the mild variability in the results would really have any bearing on the reliability and validity of the results.
Post by: MLGityaJ^A on November 11, 2017, 04:50:29 pm
The sample solutions say nothing about precision. Reducing the effect of random error does make the results more accurate. Error means that the results are inherently inaccurate; therefore, by removing error we increase accuracy. The sample solutions perhaps should have mentioned accuracy directly.
I'm pretty sure random errors don't make the results less accurate. When random errors occur, they result in a high amount of variation within the results. This means that random errors affect precision rather than accuracy. The one kind of errors that can affect accuracy are systematic errors, where the equipment being used consistently gives values deviate away from the true value. Not all errors affect accuracy. The effect of random errors can be lessened by repeating measurements to obtain a more precise average, but this is not what question 11.c. is talking about.
Post by: vox nihili on November 11, 2017, 05:14:36 pm
I'm pretty sure random errors don't make the results less accurate. When random errors occur, they result in a high amount of variation within the results. This means that random errors affect precision rather than accuracy. The one kind of errors that can affect accuracy are systematic errors, where the equipment being used consistently gives values deviate away from the true value. Not all errors affect accuracy. The effect of random errors can be lessened by repeating measurements to obtain a more precise average, but this is not what question 11.c. is talking about.
You're right about that. The reason for that is that random errors tend to underestimate or overestimate results with the same magnitude. Systematic errors skew towards overestimating or underestimating. As such, if you take lots and lots of measurements, if you're only contending with random error you should get a result that reflects the true result; however, if you have a systematic error it won't, no matter how many measurements you take.
I don't like the way I've worded my answer to 11c. On reading your answer again, I think that you would get marks for it. It's not 100% correct, but I'm not sure VCAA will be that pedantic. For instance, if you compared 10s to 1 min, you could actually say exactly the same thing you said, despite the fact that there is actually quite a degree of change left in the system. The reality is that we do not know that at 10min we'd be getting the same results as four minutes, we're just more confident because we measured for longer.
I think the point of the four minutes is to increase one's confidence that the measurements they have obtained are a good estimate of the "true" result. That's because by taking more measurements you reduce the standard error (i.e. the degree to which the results vary based on random error alone).
Post by: Zaljc on November 15, 2017, 01:47:40 pm
It’s funny how during the exams, you read things incorrectly. But bye guys, I’m gonna go contemplate my life
Post by: Calebark on November 15, 2017, 02:05:39 pm
I JUST REALISED THAT I READ THE CHOLESTROL QUESTION WRONG ?!??! I READ WHAT HAPPENS WHEN THERE IS LOW CHOLESTROL INSTEAD OF LOVISTA OR WHATEVER IT WAS :(
It’s funny how during the exams, you read things incorrectly. But bye guys, I’m gonna go contemplate my life
I completed Biology last year. Once the AN discussion/solutions came out, I realised that I misread a lot on information. I was barely expecting to crack a 30 raw, but I managed a 39 raw. You can surprise yourself -- don't lose hope :)
Post by: ATARNOTES321 on November 16, 2017, 09:49:12 pm
For question 11d about the 'control measures', do you think they will accept having separate trials as controls (instead of writing about controlled variables)? I wrote that those trials could be used as a standard of comparison against the actual test experiment to show how the results are affected by the variable (by showing what would happen if it were kept constant in the control test)...
Hopefully this makes sense!
Thanks in advance :)
If somebody could please let me know their opinion on this I would really appreciate it! Thanks
Post by: vox nihili on November 16, 2017, 10:09:52 pm
If somebody could please let me know their opinion on this I would really appreciate it! Thanks
Sorry, missed this one. Describe the separate trials to me. Not entirely sure what you mean. Simply having separate trials is not enough to be a control.
Post by: ATARNOTES321 on November 16, 2017, 10:18:49 pm
Sorry, missed this one. Describe the separate trials to me. Not entirely sure what you mean. Simply having separate trials is not enough to be a control.
Sorry, I meant using a completely different group as a control, for example doing a seperate experiment where the temperature remained constant. Then another experiment where another variable was kept constant...I wrote that these different control groups could be compared to the regular test. Does that makes a bit more sense ?
Thanks for your reply!
Post by: vox nihili on November 16, 2017, 10:34:14 pm
Sorry, I meant using a completely different group as a control, for example doing a seperate experiment where the temperature remained constant. Then another experiment where another variable was kept constant...I wrote that these different control groups could be compared to the regular test. Does that makes a bit more sense ?
Thanks for your reply!
It's probably a bit of overkill, but that control is fine. Another potential control would be no cockroach.