Lymphocytes

Question 2

What are the 2 types of T-Lymphocyte?

Answer 2

1. T-helper cells
2. Cytotoxic (killer) T-cells

Question 3

What type of immunity are T-cells involved in?

Answer 3

cell-mediated

Question 4

What types of cells can T-helper cells respond to? Give 2 examples

Answer 4

Antigen presenting cells
- Phagocytes, that display proteins from pathogens on their cell-surface membrane
- Infected body cells, which display viral proteins
- cells which present non-self antigens
- cancer cells

Question 5

What is an antigen?

Answer 5

a molecule/protein on the cell-surface membrane that stimulates an immune response

Question 6

Once stimulated, what are 4 things a T-helper cell can do?

Answer 6

• become a memory cell
• stimulate phagocytes
• stimulate B-cells
• clones itself, and form cytotoxic T-cells

Question 7

How do cytotoxic T-cells kill pathogens?

Answer 7

By making holes in their cell-surface membranes

Question 8

Where are T-cells formed? Where do they mature?

Answer 8

formed in the bone marrow
mature in the thymus (gland)

Question 9

Where are B-cells formed? Where do they mature?

Answer 9

Formed in the bone marrow
Mature in the bone marrow

Question 10

What are the 2 types of B-cells?

Answer 10

• memory cells
• plasma cells

Question 11

Outline how T-cells are involved in the specific immune response to a pathogen

Answer 11

• specific receptors bind to the antigens that have been presented on antigen-presenting cells
• this activates the T-helper cells which then divide by mitosis
• These T-helper cells can do 1 of 4 things when activated

Question 12

What do plasma B-cells do?

Answer 12

They are involved in the production of antibodies into the bloodstream as part of the primary immune response

Question 13

How do memory cells work?

Answer 13

They remain in the body after infection. If they come into contact with the pathogen again, then they will turn into plasma cells and produce antibodies. Memory cells are part of the secondary immune system

Question 14

What is meant by the term ‘monoclonal antibodies’?

Answer 14

Many copies of the same antibody produced by clones

Question 15

What is clonal selection?

Answer 15

The rapid division and cloning of cells needed to produce antibodies. This occurs once the B-cells have been activated by the T-helper cells

Question 16

How could antigens show that animals are genetically similar?

Answer 16

• antigens coded for by genes in DNA
• if the antigens on organisms are similar then the genes must also be similar

Question 17

Why is the cell cycle/mitosis important, with link to the immune system?

Answer 17

clonal expansion to fight of pathogens