Immunity To Learn

Question 1

What is an antigen

Answer 1

An antigen is a cell surface molecule that triggers an immune response
Usually a glycoprotein, glycolipid or polysaccharide

Question 2

What happens after the lysozymes have hydrolysed the pathogen?

Answer 2

The phagocyte absorbs the products from pathogen hydrolysis
Antigens are displayed on the surface

Question 3

Role of antigen presenting cells

Answer 3

Phagocytes display antigens on cell surface
T helper cells bind and are activated
Binds to specific T and B helper cells causing clonal selection / mitosis

Question 4

What do T helper cells release ?

Answer 4

Cytokines

Question 5

Role of cytotoxic T cells

Answer 5

Release the enzyme perforin
This creates holes in the target cell membranes
Causes destruction of the cell

Question 6

What do secreted antibodies lead to

Answer 6

Agglutination

Question 7

What are antibodies and what is the structure

Answer 7

Protein secreted by plasma cell
Quaternary structure - 2 light chains held in place by disulphide bridges, 2 longer heavy chains
Binding site on variable region of light chains have a specific tertiary structure

Question 8

When antibodies and antigens bind what do they form ?

Answer 8

Antigen-antibody Complex

Question 9

What are monoclonal antibodies?

Answer 9

Antibodies produced from a single clone of B cells

Question 10

Function of memory cells

Answer 10

Can rapidly divide by mitosis if an encounter with the same pathogen occurs

Question 11

What causes antigen variability

Answer 11

-random genetic mutation causes change in base sequence
-difference sequence of codons on mRNA
-different primary structure of antigen as H bonds, ionic bonds and disulphide bridges form in different places on tertiary structure.
-different shape of antigen