B4 and B5 communicable diseases

Question 1

what are pathogens

Answer 1

microorganisms that cause disease ( bacteria, viruses, protists and fungi)

Question 2

what are viruses

Answer 2

viruses aren’t living things by themselves- they need a host cell that they can infect and take over in order to reproduce

Question 3

how do bacteria reproduce

Answer 3

by splitting in 2 called binary fission

Question 4

how do pathogens spread

Answer 4

by air (droplet infection)

direct contact (sexual, skin, blood)

by water

Question 5

what are the 5 barriers of bacteria into the body

Answer 5

skin (acidic so nothing grows and a literal barrier)

eyes ( saline solution in tears is antibacterial)

blood (wbc’s produce antibodies that kill virus and platelets that clot

stomach (HCL acid kills bacteria in food)

lungs (ciliates epithelial cells and mucus trap dirt and bacteria

Question 6

what factors affect growth rate of bacteria

Answer 6

temperature, available nutrients, pH and oxygen levels

Question 7

what is the mean division time for a type of bacteria

Answer 7

how long it takes for binary fission to occur

Question 8

what is the equation for the number of bacteria at the end of the growth period

Answer 8

bacteria at start of growth period X2 (to the power of no of dimensions)

Question 9

what did ignaz semmelweis introduce

Answer 9

the idea of hand washing in hospitals to prevent spread of disease

Question 10

what did louis pasteur show

Answer 10

that microorganisms cause disease. he also developed vaccines

Question 11

what did joseph lister introduce

Answer 11

the use of antiseptic chemicals to destroy pathogens before they cause infection in surgery

Question 12

what are 4 ways of preventing the spread of communicable disease

Answer 12

hygeine

isolating infected

destroying or controlling vectors eg mosquitos

vaccination

Question 13

what is tobacco mosaic virus

Answer 13

widespread plant pathogen that causes a distinctive mosaic pattern of discolouration on the leaves as the virus destroys the cells, affects growth as can’t photosynthesise

Question 14

what is salmonella

Answer 14

bacteria that live in the gut. found in raw meat, poultry and egg. disrupts the balance of the natural gut bacteria

Question 15

what is gonorrhoea

Answer 15

an std that can cause long term pelvic pain, infertility and ectopic pregnancy. bacterial- early symptoms include thick yellow discharge and painful urination

Question 16

what is agrobacterium tumefacians

Answer 16

a bacterium that causes crown galls (a mass of unspecialised cells that grows in joints between root and shoot)

Question 17

what is rose black spot

Answer 17

a fungal disease of rose leaves spread by wind and water that damages leaves so they drop off which affects growth as photosynthesis is reduced

Question 18

what is malaria

Answer 18

caused by parasitic protists and spread by bite of female mosquitos can be fatal, damages blood and liver cells and causes fever and shaking

Question 19

what does a lack of nitrates cause

Answer 19

lack of growth

Question 20

what is chlorosis

Answer 20

when leaves turn yellow due to lack of magnesium

Question 21

why do aphids have sharp mouthparts

Answer 21

so they can penetrate into the phloem vessels and feed on sugar rich phloem sap. they can transfer virus bacteria and fungi

Question 22

how do cellulose cell walls help defend the plant from disease

Answer 22

they strengthen the plant cells to resist invasion of microorganisms

Question 23

how does the waxy cuticle prevent the plant from disease

Answer 23

they’re on the surface so they act as a barrier to entry of pathogens

Question 24

how does bark on trees/ ayer of dead cells on stems act as a barrier from disease

Answer 24

they are hard which makes it difficult for pathogens to penetrate

Question 25

how does leaf fall prevent disease

Answer 25

when deciduous leaves fall all the pathogens attached to them leave the plant site also

Question 26

what are chemical plant defence responses

Answer 26

they produce antibacterial chemicals and there are positions to deter herbivores

Question 27

what are mechanical plant defence responses

Answer 27

thorns and hairs
leaves that droop or curl when touched
mimicry to trick animals