4.1 Communicable diseases

Question 1

tuberculosis

Answer 1

bacteria- myobacterium

Question 2

bacterial meningitis

Answer 2

bacteria

Question 3

ring rot- plants

Answer 3

bacterium

Question 4

HIV/AIDS

Answer 4

virus

Question 5

influenza

Answer 5

virus

Question 6

tobacco mosaic virus- plants

Answer 6

virus

Question 7

black sigatoka- plants

Answer 7

fungus

Question 8

blight- plants

Answer 8

protoctistan

Question 9

ringworm

Answer 9

fungus

Question 10

athlete’s foot

Answer 10

fungus

Question 11

malaria

Answer 11

protoctistan

Question 12

what is malaria caused by?

Answer 12

a person with malaria has gametes of plasmodium in blood
female anopheles mosquito sucks blood
plasmodium develops goes to salivary glands
bites an uninfected person
goes to liver, then blood (repeats)

Question 13

physical plant defenses against pathogens

Answer 13

cellulose cell wall
lignin thickening
waxy cuticles
bark
stomatal closure
callose

Question 14

primary defenses against pathogens in animals

Answer 14

the skin
blood clotting and skin repair
mucous membranes
inflammation
antibodies in tear fluid

Question 15

How does antibody structure help its function?(7)

Answer 15

2 light chains and 2 heavy chains / 4 polypeptide
chains ;
variable region allows , binding / attachment , to
antigen ;
two variable regions allow binding of more than
one (of the same) antigen ;
variable region on different antibodies allows specificity
to different antigens ;
constant region allows , recognition by / attachment to / binding to , (named) phagocytes ;
hinge (region) allows flexibility ;
disulfide , bonds / bridges , hold , polypeptides / light
and heavy chains , together ;

Question 16

What is neutralisation?

Answer 16

cover / block , binding site / antigen / receptor site (on
pathogen) ;
bind to toxins ;
prevent , binding / entry , to (host) cell ;

Question 17

What is agglutination? (2)

Answer 17

clump / bind together , (many) pathogens ;
(clump) too large to , enter (host) cell / cross
membranes ;
increase likelihood of being consumed by (named)
phagocyte

Question 18

state four means of transmission.

Answer 18

direct physical contact
faecal-oral transmission
droplet infectoin
spores

Question 19

what are opsonins?

Answer 19

proteins that bind to antigen on pathogen and allow phagocytes to bind

Question 20

how do phagocytes engulf pathogens? 5

Answer 20

recognises pathogens on antigen
cytoplasm extends around pathogen engulfing it
pathogen now contained in phagosome
a lysosome containing diestive enzymes fuses with phagosome
phaocyte presents pathogens antigens on its

Question 21

what are the 4 types of lymphocytes, and their functions?

Answer 21

killer- attack and kill host body cells displaying foreign antigens
helper - release cytokines stimulating B cels to develop and stimulate phagocytosis
regulator- shut down immune response
memory- long term immunnity

Question 22

what are secondary non specific defenses in the body? ((3)

Answer 22

opsonins (bind to one antigen on the pathoen and allow phagocytes to bind)
neutrophils
macrophages

Question 23

what are the 5 steps of the specific immune response?

Answer 23

infection of pathogen
presentation of antigens
clonal selection
clonal expansion
differentiation

Question 24

What is herd vaccination?

Answer 24

vaccinating almost all of population (80-85%)

Question 25

What is rin vaccination?

Answer 25

vaccinating people in immediate vicinity

Question 26

What is the difference between active and passive immunity?

Answer 26

active= immune system is activated and produces own antibodies
passive= when antibodies are passed on to individual through breast feeding or innjection

Question 27

what is the difference between natural and artificial immunity?

Answer 27

natural= immunity achieved through normal life processes
artificial= immunity achiived as result of medical intervention

Question 28

What is the role of callose?

Answer 28

large polysaccharide that blocks sieve tubes

Question 29

describe the steps of phagocytosis. (5)

Answer 29

pathogen recognised
pathogen enulfed
trapped in phagosome
lysosomes fuse with phagosome
digestion

Question 30

What is the difference in role of B and T lymphocytes?

Answer 30

B lymphocytes manufacture antibodies

T lymphocytes release cytokines

Question 31

What is meant by the term “vaccination”? (2)

Answer 31

artificial introduction of antigenic material

which stimulates the immune response

Question 32

distinguish between the primary defenses and secondary defenses in mammels. (2)

Answer 32

primary defences prevent pathogen from entering the body

secondary defences attack the pathogen once its in the body

Question 33

mast cells release histamine. What does histamine do?

Answer 33

cause vasodilation

capillaries more permeable to white blood cells