The Biological Question Thread

[sillysmile]

10. What exactly is a Tautomeric shift and how can it cause a mutation?
This is seriously on the course? Mao can give you a way better answer than me, since it's a chemical term but there are keto and enol forms of molecules and tautomeric shift is between them. When it happens in DNA -> mutation.

probably not specifically, but it's a good example of a possible cause of mutations.

btw, thanks again.

[stonecold]

Whoa, VCAA 2007 was a stretch!

Some difficult questions in there.

Anyone reckon this would be an acceptable answer for question 9b.

"DNA evidence which indicates a reduction in production of fibrous proteins such as keratin, which could indicate less hair production and would likely coincide with when humans began wearing clothes."

[Jdog]

i don't think so ,

becuase less hair wasn't a direct conseqeunce of cltohes it was becuase body was more exposed to sunlight, I m pretty sure we began losing hair before cltohes.

[stonecold]

i don't think so ,

becuase less hair wasn't a direct conseqeunce of cltohes it was becuase body was more exposed to sunlight, I m pretty sure we began losing hair before cltohes.

fair enough.

[matt123]

Whoa, VCAA 2007 was a stretch!

Some difficult questions in there.

Anyone reckon this would be an acceptable answer for question 9b.

"DNA evidence which indicates a reduction in production of fibrous proteins such as keratin, which could indicate less hair production and would likely coincide with when humans began wearing clothes."

Probably not

I think my answer was relevant though

We began wearing clothes when the female decided to run shit their way
No more needs to be said.

[stonecold]

Whoa, VCAA 2007 was a stretch!

Some difficult questions in there.

Anyone reckon this would be an acceptable answer for question 9b.

"DNA evidence which indicates a reduction in production of fibrous proteins such as keratin, which could indicate less hair production and would likely coincide with when humans began wearing clothes."

Probably not

I think my answer was relevant though

We began wearing clothes when the female decided to run shit their way
No more needs to be said.

llollll! that was good :p

[masonnnn]

"6. What are the differences between a microsatellite and a STR? and are these sections of DNA mainly used fro DNA fingerprinting and profiling?"

I know about STR's but I actually haven't heard of microsatellites?
do we need to know them well?

[slothpomba]

Where did that question come from?

Wikipedia says theyre the same thing... "Microsatellites, also known as Simple Sequence Repeats (SSRs), or sometimes Short Tandem Repeats (STRs), are repeating sequences of 1-6 base pairs of DNA.[1]"

*shrug*

(I haven't heard of them either)

[masonnnn]

it was just sillysmile's question from the last page but yeah, left me lost as i hadn't heard of them at all (haven't seen it in any exams or anything either)

STR's are solely useful for dna profiling, yus?

[slothpomba]

Yeah not much else...(Dont code for anything)

There may be a subtle difference thought..."A short tandem repeat (STR) in DNA occurs when a pattern of two or more nucleotides are repeated and the repeated sequences are directly adjacent to each other. The pattern can range in length from 2 to 50 base pairs (bp) (for example (CATG)n in a genomic region) and is typically in the non-coding intron region"... seems longer but besides from that i cant see much, i wouldnt let it keep me up at night anyway

[masonnnn]

if ~50 base pairs of length is the only difference i wouldn't imagine there'll be any questions concerning it then, short tandem repeats should be enough, thanks man

[golden]

VCAA lists this as part of the course:

Application of gene technologies: cloning of organisms; transformation; stem cell differentiation; genetic screening, gene therapy.

How much do we need to know about cloning of organisms? Would we be required to state the steps in cloning techniques?
With gene therapy what would be a VCAA friendly response with regards to the process?

How much do we need to know about stem cell differentiation?
Embryonic stem cells can differentiate into any cell, however the removal will consequently prevent the embryo from further development and 'die'.
Adult stem cells are more specialised.
There are many ethical issues associated with this research.
(Any more?)

Can anyone add to that list of what we have to know - addressing any of these topics would be appreciated - cloning of organisms; transformation; stem cell differentiation; genetic screening, gene therapy.

[masonnnn]

for cloning http://vcenotes.com/forum/index.php/topic,30868.0.html

i must admit in class we didn't go over this dotpoint of the course in huge detail, lots of people i've heard didn't even know it was a part of the course.
therefore this, backed up with the fact that exams i've seen usually ask questions about these whereas the whole thing is explained in the question seems to indicate a pretty general knowledge is enough.

Gene Therapy would be the insertion of a functioning gene into an organism so as to allow normal function/ production of necessary proteins.
a neap question on this got me because it has to be remembered that the non-functioning gene isn't "replaced", it would still be present yet a new functioning gene also present.
Also that you can discuss the affects that these have on allele distributions in human population
And maybe one or two pre-prepared ethical issues ( haven't thought of these myself yet)

I've seen questions on this point in neap exams but i haven't noticed it much in vcaa. Bit odd.

[cypriottiger]

well i gave my detailed explanation on cloning in the thread, i think u were there lol, so id rather not repeat.
stem cells come in 3 forms
totipotent- can differentiate into any cells (taken from 2-8 cell embryos)
pluripotant- can differentiate into most cells (taken from inner lining of embryos)
multipotent- can only differentiate into a specific cell (taken from adult bone marrow cells, adult stem cells)

genetic screening involves the analysis of one's DNA in order to determine if genetic disorders exist. this is usually associated with the interruption of speciation in humanity, so you can go on to say that through treatments those that would usually be deemed 'unfit' due to genetic disadvantages are able to survive well enough to yield children, thus giving rise to more people able to carry that disadvantaged allele, and so increasing the allele frequency of a condition that would otherwise decrease by natural selection.

gene therapy involves the therapeutic process by which genes that are lacked by someone with an untreatable, inherited condition are cultured and implated into the specific cells as treatment. disadvantages include the safety of the process and how not all cells can have genes introduced to them (eg. brain cells). cells ideal for gene therapy include adult bon marrow cells as they are in constant supply, and divide motitically to yield more cells with the introduced gene. viruses and liposomes are usually used as vectors for gene therapy, as the viruses will find a host and transmit its DNA (and the desired gene) into the cell.

[sillysmile]

well i gave my detailed explanation on cloning in the thread, i think u were there lol, so id rather not repeat.
stem cells come in 3 forms
totipotent- can differentiate into any cells (taken from 2-8 cell embryos)
pluripotant- can differentiate into most cells (taken from inner lining of embryos)
multipotent- can only differentiate into a specific cell (taken from adult bone marrow cells, adult stem cells)

you forgot omnipotent: Having unlimited authority or power and can differentiate into every single cell at the same time(taken from the awesomeness cells of a deity/god ).