Lymphocytes

Question 1

What are the 2 types of T-Lymphocyte?

Answer 1

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

Question 2

What type of immunity are T-cells involved in?

Answer 2

cell-mediated

Question 3

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

Answer 3

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

Question 4

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

Answer 4

• stimulate phagocytes
• stimulate B-cells (by producing cytokines)
• stimulates or become memory cells
• activates cytotoxic T-cells

Question 5

How are cytotoxic T-cells involved in cell-mediated immunity?

Answer 5

kill any antigen presenting cells (such as infected host cells) therefore killing the pathogen inside it

Question 6

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

Answer 6

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

Question 7

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

Answer 7

Formed in the bone marrow
Mature in the bone marrow

Question 8

What are the 2 types of B-cells?

Answer 8

• memory cells
• plasma cells

Question 9

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

Answer 9

• 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 10

What do plasma B-cells do?

Answer 10

produce antibodies into the bloodstream as part of the primary immune response

Question 11

How do memory cells work?

Answer 11

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 12

What is meant by the term ‘monoclonal antibodies’?

Answer 12

Many copies of the same antibody produced by clones

Question 13

What is clonal selection?

Answer 13

The process of matching the antigens on an antigen presenting cells with the antigen receptors on B and T lymphocytes.

Question 14

How could antigens show that animals are genetically similar?

Answer 14

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

Question 15

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

Answer 15

clonal expansion to fight of pathogens

Question 16

What do B cells have on their cell-surface membrane which allows them to respond to pathogens?

Answer 16

a glycoprotein receptor made from part of an antibody, which can combine to one type of antigen

Question 17

What happens when an antigen enters the body for the first time?

Answer 17

• small numbers of B-lymphocytes with receptors complementary to that antigen
• stimulated to divide by mitosis

Question 17

What happens after clonal selection?

Answer 17

clonal expansion

Question 18

Give one differences between b plasma cells and b memory cells

Answer 18

• memory cells remain in the blood for longer
• whereas plasma cells are short lived

Question 19

What do plasma cells secrete?

Answer 19

antibodies

Question 20

What do T cells have on their cell-surface membrane which allows them to respond to pathogens?

Answer 20

receptors complementary to a specific antigen

Question 21

What activates T lymphocytes?

Answer 21

the binding of antigens when they are presented by antigen presenting cells