VCE Biology Question Thread

[sweetcheeks]

Do some organisms obtain water from the water that is produced in aerobic respiration in the electron transport chain if they do not have any water available?

That certainly does happen. It is quite common for desert dwelling organisms to do this.

[klippo]

Do we need to know the exact steps for DNA sequencing? Thanks!!

[homosapien]

Can someone please explain the difference between MHC- I and II markers and how these relate to antigen presenting cells? Because cells with MHC-I markers can also present antigens so what is the difference? thanks

[hodang]

Can anyone explain how vcaa would want to answer a pedigree if it were to be:

" X-linked" Dominant and "X-linked" Dominant

Specifically for why it's X-linked than autosomal?

[sweetcheeks]

Can anyone explain how vcaa would want to answer a pedigree if it were to be:

" X-linked" Dominant and "X-linked" Dominant

Specifically for why it's X-linked than autosomal?

Affected fathers will have daughters with the trait but none of their sons has this trait.

[sweetcheeks]

Do we need to how much NADH etc. is produced during each stage of Aerobic respiration? or is simply listing it acceptable (I know that we need to know ATP amount).

[The Usual Student]

Do we need to how much NADH etc. is produced during each stage of Aerobic respiration? or is simply listing it acceptable (I know that we need to know ATP amount).

my teacher said we don't need to and they shouldnt ask it ( some prac exams I did have asked for it )

[QueenSmarty]

For the 2015 exam (Q4b), the exam report says  "It is important to note that T cells are in both immune responses". So, would that mean that my answer of "The cell-mediated response involves the action of cytotoxic T cells, whereas the humoral response does not involve cytotoxic T cells" be incorrect? I know that T helper cells are involved in the humoral response but I don't think I've read anywhere
that cytotoxic T cells are involved in the humoral response

[plsbegentle]

For the 2015 exam (Q4b), the exam report says  "It is important to note that T cells are in both immune responses". So, would that mean that my answer of "The cell-mediated response involves the action of cytotoxic T cells, whereas the humoral response does not involve cytotoxic T cells" be incorrect? I know that T helper cells are involved in the humoral response but I don't think I've read anywhere
that cytotoxic T cells are involved in the humoral response

the question asks for two differences, you have only given one.

EDIT: a better answer would be saying that humoral reponse involves B cells and the production of antibodies while cell-mediated involves T-cells and the action of cytotoxic cells to kill infected cells by "punching holes in there membrane.

EDIT2 eheh: yeh cytotoxic t cells are not involved in the humoral reponse, helper t cells are because they stimulate b cells by releasing cytokines.

[Gogo14]

What does swelling in the lympnodes indicate?
 The question shows a graph of T cell concentration decreasing and a graph of HIV concentration increaseing

[QueenSmarty]

the question asks for two differences, you have only given one.

Forgot to mention, I did give 2 differences. I just asked about that second dot point haha

[vox nihili]

What does swelling in the lympnodes indicate?
 The question shows a graph of T cell concentration decreasing and a graph of HIV concentration increaseing

Spoooky because I'm procrastinating right now from writing notes about this :p


It's just indicative that despite the death of T-cells there is an immune response to HIV, so the swelling is all the cytotoxic T-cells and B-cells that are rproducing.

[Springyboy]

Do we need to know the exact steps for DNA sequencing? Thanks!!

Yes it's been asked before in unit 4 vcaa exams you've even had to sketch it in the past see vcaa 2012 exam 2

[vox nihili]

Yes it's been asked before in unit 4 vcaa exams you've even had to sketch it in the past see vcaa 2012 exam 2

Just to be clear, you need to know about replication, not sequencing

[Butterflygirl]

I find it kind of odd that there hasn't been many/any questions on osmosis, diffusion etc. (hypotonic, hypertonic). So maybe it will pop up in this years exam?

Also, what's the definition of diffusion, is this one okay:

Diffusion is the passive net movement of molecules from a region of high solute concentration to a region of low solute concentration.

One more question, do you think we need to know how to draw a phylogeny? like the one below

http://guestblog.scientopia.org/wp-content/uploads/sites/35/2012/07/Fred1.gif