HSC Biology: Answers & Discussion

[ehatton2016]

I put A for Q19, C for Q20, there is no evidence in the extract to suggest that its D, plus how could an immune response occur against the specific cancer cells if they do not display a specific antigen? Also, question was fucked ahah

Can anyone explain why the answer to Q13 was B and not D, it asked about segregation not assortment??

Thanks guys!!!

[naomisirmai]

Hello, it is I - the med student.
I say 20 is C because of the theory of Clonal Selection.
Plus all the others sound wrong.

It's an extremely confusing question though.

[Sanaz]

Hello, it is I - the med student.
I say 20 is C because of the theory of Clonal Selection.
Plus all the others sound wrong.

It's an extremely confusing question though.

Hey Naomi do we still have a chance of scraping band 6? I know I got 14/20 for multiple choice (cries) which means I only have 4 marks left to mess up in Section 2 and 3 :O

[ihardie]

Pretty sure the answer to question 20 is C because:
A. T cells don't produce antibodies
B. Cytotoxic T cells don't activate B cells, helper T cells do
D. B cells don't destroy antigens, they just produce antibodies which mark antigens for destruction by macrophages

 

[Bestintheworld]

Hey Naomi do we still have a chance of scraping band 6? I know I got 14/20 for multiple choice (cries) which means I only have 4 marks left to mess up in Section 2 and 3 :O

That's not true, you can afford to lose more marks than that because it undergoes scaling and other stuff. If you get about 85 raw, you can still get a band 6

-
I did D for Q20 but now that I think about it, C sounds more convincing.

[alanabb]

I put a) for 19. It had weird wording, but I thought it couldn't be d) because it should say that the body cannot *usually* mount an immune response against cancer cells. Because technically, according to the extract, the body can, but only after vaccination.

 I did c) for 20, because a) is wrong. I always thought that b cells produced antibodies which immobilise but do not kill the cell, so it couldn't be d). So I said c, which is also kind of relevant to the clonal selection theory.
Not sure though, just thoughts.

[jnicko989]

I got A for question 20 - Cytotoxic t cells don't activate B cells, c is irrelevant, and B cells never destroy anything - they trap them and take the to lymph nodes/have markers that detect antigen markers but again, don't destroy.

[alanabb]

I got A for question 20 - Cytotoxic t cells don't activate B cells, c is irrelevant, and B cells never destroy anything - they trap them and take the to lymph nodes/have markers that detect antigen markers but again, don't destroy.

Hmmm I wondered about that, but for A) I know that Helper T-Cells release interleukins that activate B cells that produce the relevant antibodies, but I thought there was a difference between acting as a messenger to B cells and actually producing antibodies? The wording of the question is *produce* and  T cells definitely don't produce antibodies. That's why I think it could be c), because the interleukins produced by the helper T Cells activate replication of the relevant T and B cells (lymphocytes) according to the clonal selection theory.

[Potato101]

Hello, it is I - the med student.
I say 20 is C because of the theory of Clonal Selection.
Plus all the others sound wrong.

It's an extremely confusing question though.

I put c)

[Zaenab Almayahi]

Any suggested answers for the option section? (communication)

[kevin217]

Did the graph need to be in pen because I drew in pencil?

[:3]

For question 19, it's asking for what can be inferred from scientist's discovery.
- Since it says "antigen extracted from patient's melanoma cells...injected...stimulates a response", it can be 'inferred' (deduced) that the body does 'mount an immune response against cancer cells' and hence, cannot be D.
- It couldn't be C as it is a reaction to an antigen.
- According to the definition of 'self-antigens' (any molecule or chemical group of an organism which acts as an antigen in inducing antibody formation in another organism but to which the healthy immune system of the parent organism is tolerant), it is made evident that it cannot be B as the other person's body does react to it.
- Therefore leaving A.

For 20, its possible they may double up on the answer (seen it done previously in past exams).
- C is valid as it does cause lymphocytes (i.e. cytotoxic T cells + B Cells) to duplicate.
- D can also be valid as it does not explicitly state how the B cell destroys the melanoma cell.
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Kevin 217, it says you're allowed to use pencil to draw diagrams (i.e. graphs), so it should be ok :3

[stephanieazzopardi]

Hello, it is I - the med student.
I say 20 is C because of the theory of Clonal Selection.
Plus all the others sound wrong.

It's an extremely confusing question though.

I agree with Naomi, the answer must be C because T cells don't produce antibodies (A), cytotoxic T cells don't activate B cells, helper T cells do (B), and D cannot be right because B cells don't directly destroy the antigen (the melanoma cells), they differentiate into plasma cells which then release antibodies to fight the antigen.
Btw, I aint no Med student but I study Speech Path and we learn this stuff for fun coz why not.
 

[RuiAce]

Did the graph need to be in pen because I drew in pencil?

Graphs in science are supposed to be drawn with pencil

[kevin217]

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Kevin 217, it says you're allowed to use pencil to draw diagrams (i.e. graphs), so it should be ok :3

Ok good thanks