communicable diseases

Question 1

parasite (3)

Answer 1

lives in host gains nutrition on host and harms host (host has to be mentioned atleast once)

Question 2

why is malaria common in hot places (1)

Answer 2

. suitable temperature for MOSQUITO .more MOQUITOS live there .POOR methods of prevention- less effective

Question 3

Suggest two reasons why governments in parts of the world other than tropical areas, are also becoming increasingly concerned about malaria. (2)

Answer 3

climate change / global warming / , may result in spread to other parts of the world / AW ;

idea of increased movement of (infected) people ;

idea that (non-malaria) countries fund anti-malaria measures via international aid ;

resistance of , parasite to drugs / mosquito to insecticides ;

Question 4

the process of agglutination and neutralisation (4)

Answer 4

neutralisation- antibody binds to binding site (1) prevent pathogen entry into the host cell (1)

agglutination : pathogens clump together (1) , therefore clump is too large to enter hsot cell (1) and pathogen are more likely to be consumed by phagocyte (1)

Question 5

The term immunity is often used when describing how vaccines work. In a piece of school homework a student wrote: “Bacteria can evolve quickly and many are now immune to antibiotics.” Explain why the student’s use of the word ‘immune’ was incorrect

Answer 5

bacteria is resistant to antibiotics (1) as immunity involves the cells white blood cells/ immune system (1) and immunity only occurs in multicelllular organism (1)

Question 6

Why are phagocytes referred to as secondary defenses

Answer 6

because they are involved after pathogen enters body

Question 7

how to phagocytes get into tissue fluid : (2)

Answer 7

multilobed nucleus , so they can squeeze through capillary pores!

Question 8

describe the stages of phagocytosis after the pathogen has reach the membrane of the phagocyte? (7)

Answer 8

pathogen is engulfed by the phagocyte (1) via phagocytosis (1) which forms a phagosome (1) whcih then fuses with a lysosome to form a phagolysosome (1) . the phagolysosome releases nezymes which digests the pathogen (1) to amino acid/sugar/glycerol (1)

1 mark for QWC

Question 9

Bacteria that causes TB

Answer 9

M bovis

( myobacterium )

Question 10

causes for the rapid spread of disease in poor areas

Answer 10

overcrowded / AW (living space)

; poorly ventilated (living space)

; poor diet / malnourished ; poor health ; homelessness ;

idea that more likely to consume , meat / milk, from infected cattle ;

idea of vaccination / medical treatment , more difficult to access ;