6.2

Question 1

virus reproduction

Answer 1

main way is to cause the lysis of host cell
two life cycles

Question 2

influenza

Answer 2

respiratory disease
short incubation period
mutate frequently so overcome immune response
3 strains
antigen markers e.g H1N1
transmitted mainly airbone or contact with animal dropings or surfaces (formites)

Question 3

zoonotic infection

Answer 3

infection that crosses the species barrier

Question 4

mode of infection of influenza

Answer 4

infect the ciliated epithelial cells of the respiratory system
lytic cycle
death of cili leave airways open to infection
causes fever etc and can last 5-7 days
exhaustion for 6-12 weeks

Question 5

treatment of flu

Answer 5

no cure
vaccines
spreads as people carry on with flu and spread it
anti viral medicines

Question 6

fungi

Answer 6

eukaryotic organisms that have cell walls made of chitin and glucans
reproduce using spores
cannot photosynthesise

Question 7

stem rust fungus

Answer 7

Puccinia graminis
feeds on tissue of host
transmitted through spores

Question 8

stem rust fungus mode of infection

Answer 8

spore land on plant -need water
hypha emerges from spore and penetrates stomata
hypha secretes enzymes e.g cellulases which digest plant cells
this causes rusty red pustules 7-15 days after which contain spores

Question 9

pathnogenic affects of srf

Answer 9

absorbs nutrients reducing yeild
less glucose to form starch
epidermis is broke so harder to control transpiration
weakens stems
damages vascular tissue

Question 10

controlling srf

Answer 10

bigger spaces between plants
reducing use of fertilisers
earlier maturing crops
fungicides - unprofitable

Question 11

protoza

Answer 11

unicellular eukaryotic organisms

Question 12

malaria

Answer 12

plasmodium falcoparum
malaria vector feeds on living tissue
female anopheles mosquito when pregnant
transmitted through blood anticoagulant released and malaria passes through both ways
affects liver and red blood cells
lytic cycle - asexual 48-72 hours
some become gamocytes and and transmitted to a mosquito

Question 13

pathogenic affect of malaria

Answer 13

flu like symtoms
long term liver damage
reduction in number of red blood cells
mostly affects weak immune system
hidden in cells so immune system find hard to destroy

Question 14

endemic disease

Answer 14

disease constantly present in an area
e.g chickenpox in uk

Question 15

problems of endemic

Answer 15

large area
hard to track the source
requires the cooperation of large numbers
expensive

Question 16

treatment of malaria

Answer 16

medication immediately after infection
anti malaria medicines before travel
antigens frequently change
mosquito nets and screen
insect repellent
long sleeves

Question 17

preventing mosquitos breeding

Answer 17

remove breeding sites e.g standing water
disposal of sewage
biological control - add organisms that kill mosquito larve to water
chemical control - pecisticdes

Question 17

issues of preventipn of malaria

Answer 17

social - people need to change
economical - require money
ethical - forcing vaccinations killing mosquitos

Question 18

delay of lysis

Answer 18

synthesis of dna
protein synthesis
assembly of new viruses

Question 19

why does lactose not activate yeast

Answer 19

does not have appropriate enztmes
sugars in cytoplasm are respired

Question 20

bacteria testing

Answer 20

isolate bacteria
gram staining
antibodies against it
look at colonies to see if they have characteristics
selective media

Question 21

salmonella

Answer 21

gram-negative
endotoxins

Question 22

why is streak plating useful

Answer 22

only one colony can grow
colonies spread out on agar
separating individual bacteria
so colonies are separated
so only 1 type of bacteria can be picked up