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IMMUNOLOGY SCIENCE AQA - A LEVEL BIOLOGY EXAM
WITH CORRECT ANSWERS
- cytotoxic cells
what are killer t-cells?
- bind to non-self antigens
1. virus attaches to and enters host cell
2. viral DNA causes host cell to express viral
how to killer t-cells work? antigens on its surface
3. killer t-cells attaches to viral antigens on infected cells
4. killer t-cells induces death of infected cell (apoptosis)
what is apoptosis? programmed cell death
- cancerous = mutations
how do killer t-cells - mutations = abnormal antigens
destroy cancer? - killer t-cell binds to abnormal antigens
- killer t-cells induces death of cancerous cell
creates holes in the cell membranes in order to
What does perforin do?
destroy the infected cell
- produce cytokines
- cytokines stimulate b-cells to divide into plasma
what do helper t-cells do?
and memory cells
- activate killer t-cells
help humoral response by involvement in the
define helper t-cells
maturation of b- cells and by triggering the
production of antibodies by b-cells
- halt immune response
- prevent wastage of energy and resources
what do suppressor t-cells
- prevent overactive immune response
do?
- causes reduction of white blood cells after being ill
work in the same way as memory b-cells, ensuring
define memory t-cells
rapid response on subsequent exposure to the same
non-self antigens
regulate the immune response by suppressing activity
define suppressor t-cells
of killer t- cells and b-cells
define 'microorganism' organism that is too small to be seen without a microscope
, 2
define 'pathogen' microorganism that causes disease
1. phagocyte follows conc gradient of chemoattractants
2. phagocyte attaches to pathogen
3. pathogen engulfed and placed in a vesicle (phagosome)
4. lysosomes migrate to phagosome and bind with
it to form a phagolysosome
outline phagocytosis --> lytic enzymes released from lysosome
5. pathogen digested
6. useful parts absorbed
7. all waste products released by exocytosis
8. non-self antigens of the pathogen
displayed on the phagocytes surface
(antigen-presenting)
where are t-cells made? thymus gland
where do b-cells mature? bone marrow
- humoral response
what do b-cells do? - release antibodies
- complementary to a specific antigen
what response are plasma primary
cells?
what response are memory secondary
b- cells?
1. antigen attaches to complementary antibody on b-cell
2. antigen taken into cell (endocytosis)
outline the humoral
3. presented on cell surface membrane
response
4. t-helper cells bind to antigen and stimulate b-cell to divide
what does mitosis do in - forms clones of b-cells (plasma and memory)
humoral response? - clonal response
each clone can produce one type of antibody
what do clones do?
(monoclonal) which can be used in medicine
- primary response
- secrete antibodies
outline plasma cells
- only survive for a few day
- slow response = person gets ill before pathogen is killed
- secondary response
- circulated in blood and tissue fluid
outline memory cells
- divide rapidly
IMMUNOLOGY SCIENCE AQA - A LEVEL BIOLOGY EXAM
WITH CORRECT ANSWERS
- cytotoxic cells
what are killer t-cells?
- bind to non-self antigens
1. virus attaches to and enters host cell
2. viral DNA causes host cell to express viral
how to killer t-cells work? antigens on its surface
3. killer t-cells attaches to viral antigens on infected cells
4. killer t-cells induces death of infected cell (apoptosis)
what is apoptosis? programmed cell death
- cancerous = mutations
how do killer t-cells - mutations = abnormal antigens
destroy cancer? - killer t-cell binds to abnormal antigens
- killer t-cells induces death of cancerous cell
creates holes in the cell membranes in order to
What does perforin do?
destroy the infected cell
- produce cytokines
- cytokines stimulate b-cells to divide into plasma
what do helper t-cells do?
and memory cells
- activate killer t-cells
help humoral response by involvement in the
define helper t-cells
maturation of b- cells and by triggering the
production of antibodies by b-cells
- halt immune response
- prevent wastage of energy and resources
what do suppressor t-cells
- prevent overactive immune response
do?
- causes reduction of white blood cells after being ill
work in the same way as memory b-cells, ensuring
define memory t-cells
rapid response on subsequent exposure to the same
non-self antigens
regulate the immune response by suppressing activity
define suppressor t-cells
of killer t- cells and b-cells
define 'microorganism' organism that is too small to be seen without a microscope
, 2
define 'pathogen' microorganism that causes disease
1. phagocyte follows conc gradient of chemoattractants
2. phagocyte attaches to pathogen
3. pathogen engulfed and placed in a vesicle (phagosome)
4. lysosomes migrate to phagosome and bind with
it to form a phagolysosome
outline phagocytosis --> lytic enzymes released from lysosome
5. pathogen digested
6. useful parts absorbed
7. all waste products released by exocytosis
8. non-self antigens of the pathogen
displayed on the phagocytes surface
(antigen-presenting)
where are t-cells made? thymus gland
where do b-cells mature? bone marrow
- humoral response
what do b-cells do? - release antibodies
- complementary to a specific antigen
what response are plasma primary
cells?
what response are memory secondary
b- cells?
1. antigen attaches to complementary antibody on b-cell
2. antigen taken into cell (endocytosis)
outline the humoral
3. presented on cell surface membrane
response
4. t-helper cells bind to antigen and stimulate b-cell to divide
what does mitosis do in - forms clones of b-cells (plasma and memory)
humoral response? - clonal response
each clone can produce one type of antibody
what do clones do?
(monoclonal) which can be used in medicine
- primary response
- secrete antibodies
outline plasma cells
- only survive for a few day
- slow response = person gets ill before pathogen is killed
- secondary response
- circulated in blood and tissue fluid
outline memory cells
- divide rapidly
