HSC Biology Marathon 2015 (4 Viewers)

[Chris_S]

Discuss the importance of the interaction between B cells and T cells in the immune response (4 marks)

Could someone please answer this as I understand what they both do but the interaction between them! As all I really said they are apart of the immune response and fight off foreign tissue etc. Could someone like write a band 6 example oft his interaction please? Thanks

 

[BlueGas]

Discuss the importance of the interaction between B cells and T cells in the immune response (4 marks)

Could someone please answer this as I understand what they both do but the interaction between them! As all I really said they are apart of the immune response and fight off foreign tissue etc. Could someone like write a band 6 example oft his interaction please? Thanks

B and T lymphocytes work together to successfully defend the body against infections, this is because of the interaction between the two which is regulated by a specific type of cytokine chemical called interleukin. MacFarlane Burnet's work known as the clonal selection theory has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens invading the body. T cells interact with antigens presented by macrophages, activated T cells then differentiate into helper T cells which produce chemicals that stimulate the growth of B cells. Without the interaction between B and T lymphocytes, the body would not be able to effectively defend against infections.

 

[Queenroot]

B and T lymphocytes work together to successfully defend the body against infections, this is because of the interaction between the two which is regulated by a specific type of cytokine chemical called interleukin. MacFarlane Burnet's work known as the clonal selection theory has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens invading the body. T cells interact with antigens presented by macrophages, activated T cells then differentiate into helper T cells which produce chemicals that stimulate the growth of B cells. Without the interaction between B and T lymphocytes, the body would not be able to effectively defend against infections.

They destroy the pathogen, not the antigen. The antigen-antibody complex is a medium by which the pathogen is destroyed.

Inactivated T-cells become activated by interacting with antigens presented by the macrophages. They then signal B cells to replicate and produce antibodies.

Essentially what you wrote is correct, but phrasing it better can make a difference.

 

[BlueGas]

Describe how the contribution of Robert Koch has changed our understanding of diseases. (3 marks)

 

[Mr_Kap]

Describe how the contribution of Robert Koch has changed our understanding of diseases. (3 marks)

Robert Koch though experimenting with Anthrax disease in sheep, proved that micro-organisms (microscopic pathogens) are responsible for diseases. This contribution was immense and has changed our understanding of diseases as previously it was not known the cause of diseases. First Koch found bacteria in sheep infected with anthrax. Then, he placed the bacteria on agar plates in Petri dishes so that many colonies of the bacteria were produced. He used bacteria from these colonies to infect healthy sheep and found that they became infected.Here he developed "Koch's Postulates" which is used to identify the cause of an infectious disease, hence our understanding of diseases, has greatly benefited from Koch's contriutions. These postulates are as follows: Firstly, the micro-organism must be present in all subjects with the disease. Next, the same micro-organism must be extracted from all subject. Then, the micro-organism must be reinserted into a healthy host, which develops the same disease and symptoms. Finally, the micro-organism must be extracted from this newly infected host, and must be identical to the first micro-organism extracted.


I answered this more like a 4 marker..

 

[BlueGas]

Describe a method you used to model natural selection. (3 marks)

 

[Queenroot]

Describe a method you used to model natural selection. (3 marks)

The bachelorette

 

[BlueGas]

The bachelorette

What's a limitation with this?

 

[Queenroot]

What's a limitation with this?

Makes ur IQ drop

 

[Chris_S]

Is biochemical analysis the same as biochemistry? If not what is the difference?

 

[Mr_Kap]

Is biochemical analysis the same as biochemistry? If not what is the difference?

Biochemical analysis is what they do in biochemistry. i think.

 

[Chris_S]

Biochemical analysis is what they do in biochemistry. i think.

That is what I thought, then someone said it wasn't!

 

[Mr_Kap]

Discuss TWO sources of variation that can occur during meiosis,explaining how this leads to genetic diversity. 4 or 6 MARKS (u choose)

 

[Flop21]

Biochemical analysis is what they do in biochemistry. i think.

So this is for the evidence for evolution dotpoint right, biochemistry is the topic or broad area describing the study of things on a molecular level. Biochemical analysis is analysing the things that fall under the biochemistry area i.e. molecules. So for example, it would involve amino acid sequencing, DNA-DNA hybridisation etc.

I think?

 

[Mr_Kap]

So this is for the evidence for evolution dotpoint right, biochemistry is the topic or broad area describing the study of things on a molecular level. Biochemical analysis is analysing the things that fall under the biochemistry area i.e. molecules. So for example, it would involve amino acid sequencing, DNA-DNA hybridisation etc.

I think?

yeh i thought that as well.

 

[Flop21]

Hey guys you know the big markers, like 7-8, why is it that in some past papers I do there's not a lot of lines?? I'd wanna be able to write at least 1 page and a bit for an 8 marker, but how do we do that when there's so little space? Is there spare booklets to write extra?

 

[Mr_Kap]

Hey guys you know the big markers, like 7-8, why is it that in some past papers I do there's not a lot of lines?? I'd wanna be able to write at least 1 page and a bit for an 8 marker, but how do we do that when there's so little space? Is there spare booklets to write extra?

Yeh there are extra booklets you can use. But idk, maybe they want concise answers. I remember seeing on the HSC chem marking guidlines (i cant remember which year), for a 7 marker, that having a clear, succint answer with no irrevelant information was worth 1 mark.

 

[Mr_Kap]

What is the difference between a nerve impulse, electrochemical signal, and an electrical signal?

 

[Flop21]

Yeh there are extra booklets you can use. But idk, maybe they want concise answers. I remember seeing on the HSC chem marking guidlines (i cant remember which year), for a 7 marker, that having a clear, succint answer with no irrevelant information was worth 1 mark.

Ahh, see the higher marked questions like the 7s and 8s I get confused with just because I don't know how much to write. Usually I just write as much as I can because I don't want to lose marks for not having something.

What is the difference between a nerve impulse, electrochemical signal, and an electrical signal?

A nerve impulse is an electrochemical signal, which I suppose is also an electrical signal. Aren't they all really the same thing?

 

[Mr_Kap]

Ahh, see the higher marked questions like the 7s and 8s I get confused with just because I don't know how much to write. Usually I just write as much as I can because I don't want to lose marks for not having something.



A nerve impulse is an electrochemical signal, which I suppose is also an electrical signal. Aren't they all really the same thing?

Yeh, usually i try and write as much as i can as well. Just try to make sure its relevant though, even if you write heaps.

And yeh, I thought they were the same thin but i was just checking in case i was wrong.