cell recognition and immune system - 2

Question 1

antigen definition

Answer 1

molecule that triggers an immune response by lymphocytes

Question 2

pathogen definition

Answer 2

organisms that cause disease

Question 3

phagocyte definition

Answer 3

type of white blood cell that carries out phagocytosis

Question 4

how do phagocytes work (5 points)

Answer 4

1. phagocytes recognises foreign antigens
2. cytoplasm of phagocyte moves around the pathogen and engulfs it
3. pathogen is in a phagocytic vacuole in the cytoplasm of the phagocyte
4. lysosome fuses with phagocytic vacuole and breaks down the pathogen
5. phagocyte presents pathogen’s antigens - sticks the antigens on its surface to activate immune system cells

Question 5

2 types of T-cells

Answer 5

cytotoxic cells
helper cells

Question 6

word where pathogens clump together

Answer 6

agglutination

Question 7

antibody definition

Answer 7

protein produced by lymphocytes in response to the presence of the appropriate antigen

Question 8

antigens enable the immune system to identity….

Answer 8

1. pathogens
2. abnormal body cells
3. toxins
4. cells from other organisms of the same species

Question 9

where are phagocytes made

Answer 9

bone marrow

Question 10

what do neutrophils do

Answer 10

engulf and digest pathogens

Question 11

what do macrophages do

Answer 11

punch small holes in pathogen to mark the cell for destruction by neutrophils

Question 12

process of phagocytosis (4)

Answer 12

1. pathogen is recognised as ‘non-cell’ due to antigens. phagocyte attaches to pathogen
2. phagocyte engulfs the pathogen and forms and phagosome
3. phagosome and lysosome fuse together, digestive enzymes break down pathogen and hydrolyse it
4. harmless products are removed from the cell by exocytosis

Question 13

APC meaning

Answer 13

antigen presenting cell

Question 14

APC description of function

Answer 14

have a pathogenic antigen on their surface signals T-cells

Question 15

what does the cellular immune response consist of

Answer 15

T cells target pathogens within cells

Question 16

what do T helper cells do

Answer 16

stimulate and recruit more cells to assist in the immune response

Question 17

what synthesises antibodies and in response to what

Answer 17

B cells in response to antigens from a pathogens surface

Question 18

why is it important antibodies can change shape

Answer 18

so they can bind to multiple antibodies as it has an induced fit model

Question 19

why don’t vaccinations full eliminate diseases

Answer 19

different strains may form
not available to everyone
expensive
done on a large scale to achieve herd immunity

Question 20

what does AIDS stand for

Answer 20

acquired immunodeficiency syndrome

Question 21

HIV structure

Answer 21

core- RNA and proteins, reverse transcriptase
capsid- outer protein coat
envelope- made from membrane taken from host cell’s membrane
protein attachments- help the virus attach to host’s T helper cells

Question 22

simple description of how HIV replicates (4)

Answer 22

1. virus attaches
2. genes copied
3. replication
4. released

Question 23

4 ways HIV is spread

Answer 23

1. unprotected sex with someone who is HIV positive
2. blood transfusions
3. sharing needles
4. breast feeding

Question 24

3 ways the immune system can respond to antigens

Answer 24

1. lysosomes break down foreign cells
2. phagocytosis of the foreign cells
3. production of antibodies that bind to antigens and inhibit the functioning of the foreign cells

Question 25

where are the complementary receptors to antigens located in immune cells?

Answer 25

cell surface membrane

Question 26

role of T cytotoxic cells

Answer 26

kill foreign and abnormal cells

Question 27

what are antibodies made up of

Answer 27

2 heavy chains
two light chains

Question 28

which bridges are heavy and light chains connected by in antibodies

Answer 28

disulphide bridges

Question 29

6 steps of HIV replication

Answer 29

1. bind to T helper cells
2. release of the capsid
3. reverse transcriptase
4. intergrase
5. expression
6. release of HIV

Question 30

what structure encloses the capsid in HIV

Answer 30

the viral envelope

Question 31

2 examples of cells that are activated by T helper cells

Answer 31

1. phagocytes
2. B cells

Question 32

3 ways antibodies help stop a pathogen

Answer 32

1. agglutination
2. neutralisation
3. osponisation