Biology AQA Immuonolgy

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Phagocystosis:

1

1. bacteria emits hormones which attracts phagocyte.

2. phagosome is formed, and lysosomes emit lytic enzymes

3.these enzymes breakdown and digest bacteria- destroying it

A

ANTIGEN- A toxin/ foreign protein on the surface of cells which causes an immune response

ANTIBODIES- it is specific to certain antigen and causes the breakdown of antigens during immune responses

the variable regions are specific to certain antigens. antibodies are proteins made up of peptide bonds and amino acids.

Antibodies form Antigen-antibody complexes

(they're similar to enzymes apart from their function)

Cellular response: T-cells and other immune system cells that they interact with.

Humoral: B-cells and the production of ant-bodies

Cellular response:

T-cells enculf pathogens/bacteria/cancerous cells and pagcytosis occurs. The T-cells become Antigen presenting cells and present them on their surface to trigger an humoral response.

Humoral response:

B-cells produce antibodies and memory cells which attack the antigens. The memory cells mean they on a pre-infection antigens and pathogens are destroyed more quickly.

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Plasma cells are what produce antibodies from T-cells.

Antigenic variatiation: Pathogens change the antigens on their surface affecting the immune response.

In influenza- the constant antigenic variation means new strains can be formed- making vaccinations difficult to be made.

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Vaccinations:

Dead or a small quantity of antigens- means enough memory cells can be produced to destroy it. this means if reinifected the immune system is ready to respond.

Monoclonal Antibodies:

Produced from a single group of genetically identical B-Cells.

They are very specific and have a unique structure.- this means in medicine they are produced to ensure that a specific structure is targeted.

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