AQA Biology Unit 1 January A-S 2012 *EXAM FINISHED*

Describe the gross structure of the human heart? (5)
Why do semi-lunar valves close?
What is the function of the valves?
What is the function of the AVN?
What is the function of the Bundle of His?
How do channel proteins work in facilitated diffusion?
Facilitated diffusuion depends on 3 factors? What are those?
Explain the process of Expiration? (5)
How is a dipeptide formed? (5)
What are the functions of proteins? (3)
Define Vaccine?
Define antibody?

Hey me again, is the cellular response when an infected cell uses part of the antigen in a MHC 2 protein on it's cell surface membrane to activate T-killer cells

OR

When a phagocyte digests a pathogen then presents part of the pathogen on it's cell surface membrane to activate T-helper cells?

OR are they the same thing...

Second one is correct
1) phagocyte presents antigen on its cell surface membrane
2) receptors on certain T helper cell fit exactly on to these antigens
3) this activates other t cells to divide rapidly by mitosis and form clones
4) the cloned t cells can diffrentiate into cyto toxic t cells, stimulate b cells etc


first one seems more complicated lol :/

cell mediated and humoral are very similar because they both have the activation phase. steps one two three above is where the t helper cells are activated, but then the clones that are produced will diffrentate into cyto toxic t cells ( which is explained in the link) that will kill infected cells..they do this by producing a protien which makes wholes in the membrane. so water can go in or out by osmosis and the cell will burst or shrink. ( the link has explained what the cyto toxic cells do before they have explained how they have actually come about)

Humoral immunity is when
1) the antigens of the invading pathogen are taken up by the b cell and presented on their membrane
2) t helper cells come along and bind to the processed antigens on the b cells to activate them
3) the be cells are now activated so can divide by mitosis
4) clones diffrentate into plasma cells and memmory cells and so on

Immunology will be the death of me.

So.. this The cellular response is the engulfing of a antigen by a phagocyte then breaking it down and presenting it on their cell surface membrane on a receptor protein, t-helper cells bind to this protein and then are stimulated to divide into identical clones of eachother, these t-cells can then divide into memory cells, cytotoxin cells etc

The humoral response is when a b-cell comes in contact with an antigen and the b-cell breaks the antigen down partially then presents it on its plasma membrane, the t-cells then bind to this b-cell as they have come into contact with the antigen before, the b-cells are now stimulated to divide by mitosis, these clones can then become memory cells or plasma cells.

Do we need to know how microorganisms enter the body or just how they cause disease (produce toxin + damage host tissue)?

Also if anyone has any notes on vaccination, it would be appreciated.

Do we need to know how microorganisms enter the body or just how they cause disease (produce toxin + damage host tissue)?

Also if anyone has any notes on vaccination, it would be appreciated.

I think we need to know that they can enter by like nose mouth ears etc...

But it's mostly common sense

Did not expect it to come up again, ignored the whole topic.

scraped 81ums in that paper, good thing i got 138/140 in unit 2 eh

I've already failed this exam once. Defo going to fail it again.

questions on immunity

1) define monoclonal antibodies (1)
2) state two barriers which prevent the entry of pathogens (2)
3) explain the process of phagocytosis (5)
4) Describe the role of memory cells in the immune response (4)
5) where do B lymphosytes mature? (1)
6) state two difference between T and B cells (2)
7) state and explain the two types of immunity (4)
9) Give two reason why the control of cholera by vaccination is difficult? (2)
10) Give two ethical issues associated with vaccination programmes (2)

whoever answers these question first makes their own batch of questions

questions on immunity

1) define monoclonal antibodies (1)
2) state two barriers which prevent the entry of pathogens (2)
3) explain the process of phagocytosis (5)
4) Describe the role of memory cells in the immune response (4)
5) where do B lymphosytes mature? (1)
6) state two difference between T and B cells (2)
7) state and explain the two types of immunity (4)
9) Give two reason why the control of cholera by vaccination is difficult? (2)
10) Give two ethical issues associated with vaccination programmes (2)

whoever answers these question first makes their own batch of questions

questions on immunity

1) define monoclonal antibodies (1)
2) state two barriers which prevent the entry of pathogens (2)
3) explain the process of phagocytosis (5)
4) Describe the role of memory cells in the immune response (4)
5) where do B lymphosytes mature? (1)
6) state two difference between T and B cells (2)
7) state and explain the two types of immunity (4)
9) Give two reason why the control of cholera by vaccination is difficult? (2)
10) Give two ethical issues associated with vaccination programmes (2)

whoever answers these question first makes their own batch of questions