the specific immune system (chapter 12)

Question 1

Antibodies

Answer 1

Y shaped glycoproteins called immunoglobulins which bind to a specific antigen on a pathogen that has triggered the immune response

Are made up of 2 identical polypeptide chains called the heavy chains and 2 shorter identical chains called the light chains. The chains are held together by disulphide bridges.

Question 2

How antibodies defend the body

Answer 2

Antibodies act as agglutinins caysing pathogens ti clump together, this prevents them spreading through the body and makes it easier for phagocytes to engulf them

Can act as anti toxins, binding the toxins produced by pathogens nad making them harmless

Question 3

T helper cells

Answer 3

T helper cells - produce interleukins which are a type of cytokine. They stimulate the activity of B cells which increases antibody production and attracts and stimulates macrophages to engluf pathogens with antigen-antibody complexes

Question 4

T regulator cells

Answer 4

They suppress the immune system to control and regulate it. They stop the immune response once the pathogen has been eliminated and makes sure the body recognises self antigens

Question 5

T killer cells

Answer 5

Destroy the pathogen carrying the antigen, produce a chemical called perforin which kills the pathogen

Question 6

T memory cells

Answer 6

If they meet an antigen a second time, they divide rapidly to form a hige number of clones of T killer cells to destroy the pathogens

Question 7

Cell mediated immunity

Answer 7

1, macrophages engulf and digest pathogens in phagocytosis. They process the antigens from the surface of the pathogen to form antigen presenting cells.
2, the receptors on some T helper cells fit the antigens, they produce interleukins so that more T cells divide.
3, the cloned T cells mat develop into T memory cells, produce interleukins that stimulate phagocytosis or B cells to divide or stimulate production of T killer cells to destroy infected cells.

Question 8

Humoral immunity

Answer 8

1, T helper cells bind to the B cells. This is clonal selection - when the B cell with the correct antibody is selected for cloning.
2, interleukins produced by the T helper cells activate the B cells. The actuvated B cells divide by mitosis. This is claled clonal expansion.
3, Cloned plasma cells produce antibodies to disable the pathogens.
4, some cloned B cells develop into B memory cells. The memory cells divide rapidly to form plasma cell clones eith the right antibody which wipe out the pathogen very quickly.