VCE Biology Question Thread

[cosine]

Are ribosomes organelles?  "Ribosomes are structures that are not membrane bound and are therefore not organelles".
So all organelles need to be membrane bound organelles in order to be classified as an organelles?

[cosine]

For the attached, question 22 is D, can someone tell me why 23 is A?

I thought that when T-Helper cells bind with B cells, they cause them to proliferate? I thought that T-Helper cells only activate when they bind to MHC II on APCs? Is this diagram misleading?

[Biology24123]

For the attached, question 22 is D, can someone tell me why 23 is A?

I thought that when T-Helper cells bind with B cells, they cause them to proliferate? I thought that T-Helper cells only activate when they bind to MHC II on APCs? Is this diagram misleading?

I think it's because B cells are also antigen presenting cells meaning both will proliferate

[cosine]

Some assistance would be much appreciated, thank you.

Spoiler

Need help on question 27, absolutely no idea... How can a rapid mutation rate be useful for studying the evolutionary relationships of organisms... just how..

Spoiler

For the second attachment, this is exactly what I said because the results were contradictory to what I have learnt about the allergic responses:

"The ever-increasing production of IgE antibodies in blood plasma agglutinated the antigens of the peanut proteins so the OIT is able to have peanuts, as the peanuts subsequently are unable to trigger mast cells (they have been agglutinated), whereas the control group cannot resist the protein as their immune system produces antibodies that induces allergic responses as they bind to mast cells and are triggered when the antigens of the peanut binds to them."

Stupid answer, yes, I know, probably wrong but what else could you say?

Spoiler

When a question says to determine the mode of inheritance, is it allowed if we do two points about, one talking about why it is autosomal or X-linked and the other talking about why it is dominant/recessive?

[cosine]

I think it's because B cells are also antigen presenting cells meaning both will proliferate

But if this is the case, then why would the Helper T cells even need to be activated in the first place by APCs?
Idk if this is a misleading question or not, hopefully Mr. T-Rav can enlighten us :/

[Biology24123]

But if this is the case, then why would the Helper T cells even need to be activated in the first place by APCs?
Idk if this is a misleading question or not, hopefully Mr. T-Rav can enlighten us :/

Where does it say that the T helper cell was activated

[cosine]

Where does it say that the T helper cell was activated

T Helper cells need to be activated in order to trigger/release cytokines to active B cells to proliferate

[Biology24123]

T Helper cells need to be activated in order to trigger/release cytokines to active B cells to proliferate

Yeah I know but you said "why would the Helper T cells even need to be activated in the first place by APCs?". It never said the T helper cells were activated by an APC, the B cell is an APC

[cosine]

Yeah I know but you said "why would the Helper T cells even need to be activated in the first place by APCs?". It never said the T helper cells were activated by an APC, the B cell is an APC

What? I thought that phagocytes needed to activate helper T cels first and only then they could activate B cells to proliferate?

[vox nihili]

But if this is the case, then why would the Helper T cells even need to be activated in the first place by APCs?
Idk if this is a misleading question or not, hopefully Mr. T-Rav can enlighten us :/

You're right in saying that T-cells need to be activated by antigen-presenting cells. Normally this is a dendritic cell. However, when a T-cell activates a B-cell it needs to bind it somehow. This is what the diagram depicts, an activated T-cell binding to a B-cell.

[Biology24123]

Are Kilbaha exams for Biology any good?

[pra96]

What the hell? Everyone is doing these hard as exams while the actual VCAA standard is lower.

Overkill or good measure?

[cosine]

You're right in saying that T-cells need to be activated by antigen-presenting cells. Normally this is a dendritic cell. However, when a T-cell activates a B-cell it needs to bind it somehow. This is what the diagram depicts, an activated T-cell binding to a B-cell.

Ah that's what I thought, because a video on yt told me this too a while back, but the second question for the diagram says that when the activated T cell binds to this B cell, they both proliferate. Isn't it just the B cells that proliferate upon this TCR-MHCII complex?

[sunshine98]

In VCAA 2011 U3 question 1b ,
The question pointed to chloroplast and asked the type of nucleic acid present and to explain its function-
- I wrote: cpDNA - which encodes for enzymes needed during photosynthesis
-VCAA said: (chloroplast) DNA - which controls production of proteins for photosynthesis
Do I get the two marks (one for the correct name , and one for correct explanation) ?

[Sine]

So once a dendritic cell activates a specific T-helper cell by the use of interleukin-1 a T-helper cell becomes activated,  are memory T-helper cells produced and does the single T-helper cell undergo clonal expansion?