T-LYMPHOCYTES AND CELL MEDIATED IMMUNITY Flashcards Preview

BIOLOGY - CELL STRUCTURE AND DIVISION > T-LYMPHOCYTES AND CELL MEDIATED IMMUNITY > Flashcards

Flashcards in T-LYMPHOCYTES AND CELL MEDIATED IMMUNITY Deck (13)
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1

What is an antigen

any part of an organism or substance that is recognised as non-self by the immune system

2

What are lymphocytes produced by

stem cells in the bone marrow

3

What are the 2 types of lymphocytes

1) B lymphocytes
2) T lymphocytes

4

Where do B lymphocytes mature

bone marrow

5

Where do T lymphocytes mature

thymus gland

6

What type of immunity are B lymphocytes associated with

humoral immunity

7

What type of immunity are T lymphocytes associated with

cell-mediated immunity

8

How do T lymphocytes distinguish foreign cells from normal cells (4 points)

1) phagocytes that have engulfed and hydrolysed pathogens present their antigens on their own cell-surface membrane
2) body cells invaded by a virus present antigen on cell-surface membrane
3) transplanted cells have different antigens on surface
4) cancer cells present antigens on surface

9

What are antigen-presenting cells

cells that display foreign antigens on their surface

10

What do the receptors on the T cells do

respond to a single antigen

11

What is the response of T-lymphocytes to infection by a pathogen (5 points)

1) pathogens invade body cells or are taken in by phagocytes
2) phagocyte places antigens from pathogen on its cell-surface membrane
3) receptors on helper T-cells fit onto antigens
4) attachment activates the T cell to divide rapidly by mitosis to form a clone of genetically identical cells
5) the cloned T cells either:
a) develop into memory cells that enable a rapid response to future infections
b) stimulate phagocytes to engulf pathogens
c) stimulate B cells to divide and secrete their antibody
d) activate cytotoxic T cells

12

How do cytotoxic T cells kill infected cells

by producing a protein called perforin that makes holes in the cell-surface membrane that mean it becomes freely permeable to all substances so it dies

13

What is bird flu caused by

strain of the influenza virus