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chapter 12 - communicable diseases Flashcards

1
Q

what is a communicable disease

A

diseases caused by pathogens

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2
Q

what are vectors

A

vectors carry pathogens from one organism to another

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3
Q

how are bacteria classified

A

shape - spherical, comma shaped , spiralled
cell wall - gram positive bacteria look purple blue under light microscope. Gram negative bacteria appear red. Different cell wall affects how bacteria react to different antibiotics

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4
Q

what are viruses

A

non living pathogens
has dna or rna
reproduce rapidly
bacteriophages take over bacteria cells to replicate- used to treat some diseases

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5
Q

what are protoctista ( protists)

A

single celled
protists need vector

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6
Q

what are fungi

A

multicellular
some stop plants from photosynthesising

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7
Q

how do viruses attack host

A

take over cell metabolism. Viral genetic material gets into host cell and inserts into hosts DNA. Viruse uses host genetic mechanism to replicate and burst out

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8
Q

how do protists attack host

A

digest cell content to reproduce

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9
Q

how do fungi attack hosts

A

digest living cells

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10
Q

how do toxins produced by bacteria and fungi affect host

A

toxin damages host cells by breaking down cell membrane or inactivate enzymes or interfere with genetic material so cell cannot divide

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11
Q

what is ring rot

A

bacterial disease of potatoes and tomatoes caused by gram positive bacteria
damages leaves

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12
Q

what is tobacco mosaic virus

A

virus
infects tobacco plants
damages leaves, flowers

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13
Q

what is potato blight

A

caused by protoctista
hyphae penetrates host cells destroying leaves

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14
Q

what is black sigatoka

A

banana disease caused by fungus
attacks and destroys leaves
hyphae penetrate and digest cells turning leaves black reducing photosynthesis
controlled by fungicide

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15
Q

what is tuberculosis

A

bacterial disease in humans
destroys lung tissue and supresses immune system
curable by antibiotics

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16
Q

what is bacterial meningitis

A

bacterial infection of meninges of brain which spreads into rest of body causing blood poisoning and death
protected by antibiotics or vaccines

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17
Q

what is HIV or AIDS

A

human immunodeficiency virus
acquired immunodeficiency virus
targets T cells in immune system
destroys immune system

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18
Q

how is HIV spread

A

passed on from one person to person by bodily fluids , unprotected sex, shared needles

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19
Q

how does HIV work

A

consists of RNA genetic material
contains enzyme reverse transcriptase which transcribes RNA to DNA with interacts with DNA of host cell

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20
Q

what is influenza

A

virus of epithelial cells in gas exchange system
kills epithelial cells leaving airways open to secondary infection

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21
Q

what is malaria

A

caused by protoctista plasmodium
invades red blood cell, liver and brain
prevented by insectides and nets

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22
Q

what is ring worm

A

fungal disease affecting mammals , cattles, dogs, cats, humans
causes grey white areas of skin
cured by anti fungal creams

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23
Q

what is athletes foot

A

fungal disease
form of human ring worm
digests warm moist skin between toes
use antifungal creams

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24
Q

what are direct transmissions of pathogen in animals

A

direct contact- touching
inoculation - through break in skin( sex) , animal bite ( rabies) , puncture wound
ingestion

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25
what are indirect transmissions of pathogen in animals
fomites - inanimate objects such as socks droplet infection vectors water
26
factors affecting transmission of communicable diseases in animals
overcrowding poor nutrition compromised immune system climate change culture socioeconomic factors
27
what are direct transmission of pathogens in plants
healthy plant touching part of diseased plant
28
what are indirect transmission of pathogens in plants
soil contamination vectors spread by spore through water and wind , animals and humans
29
factors affecting transmission of communicable diseases in plants
planting varieties of crops that are susceptible to disease overcrowing poor mineral nutrition damp warm conditions climate change
30
how do plants recognise attack
receptors in cells respond to pathogens which stimulates release of signalling molecules that switch on genes triggering cellular responses
31
what are physical defenses in plants
produce high level of the polysaccharide , callose, which contains b 1-3 linkages and b 1-6 linkages which deposit between cell walls near infected cells acting as barrier callose blocks sieve plates in phloem callose is deposited in plasmodesmata lignin is added
32
what are chemical defences in plants
insect repellents insectides antibacterial compounds antifungal compounds ( chitinases)
33
what are non -specific animal defences against pathogens
skin mucous membranes in airways lysozymes in tears and urine and acid in stomach
34
what is thromboplastin
an enzyme that triggers a cascade of reactions resulting in formation of blood clot
35
what is serotonin
makes smooth muscle in walls of blood vessels to contain so they narrow are reduce supply of blood to area
36
how is a blood clot formed
platelets activated by damage tissue activate thromboplastin which catalyses reaction of prothrombin with calcium ion to form thrombin. Thrombin catalyses formation of fibrin by fibrinogen which forms blood clot
37
what are mast cells
activated in damaged tissue which release histamines and cytokines
38
why do histamines do
makes blood vessels dilate causing localised heat and redness preventing pathogens to reduce histamines make blood vessel walls leaky so blood plasma is forced out to tissue fluid causing swelling and pain
39
what do cytokines do
attract phagocytes to site. They dispose of pathogens by phagocytosis
40
what does a fever do
caused by hypothalamus in brain which increase temperature so inhibit pathogen reproduction specific immune system works better at higher temperatures
41
what are phagocytes
specialised white cells that engulf and destroy pathogens
42
what are the 2 types of phagocytes
neutrophils macrophages
43
what does pus consist of
dead neutrophils and dead pathogens
44
what are the stages of phagocytosis
1) pathogens produce chemicals that attract phagocytes 2) phagocytes recognise non human proteins on pathogen. 3) phagocyte engulfs pathogen and encloses it in a vacuole called phagosome 4)phagosome combined with lysosome to form phagolysosome 5) enzymes from lysosome digest and destroy pathogens
45
what do cytokines do
act as cell signalling molecules to move phagocytes to site of infection increase body temperature and stimulate specific immune system
46
what do opsonins do
bind to pathogens to tag them so are more easily recognised by phagocytes
47
what are antibodies
Y shaped glycoproteins called immunoglobin which bind to specific antigen on the pathogen that triggered immune response
48
what are antibodies made of
2 identical long polypeptide chains called heavy chains 2 identical short polypeptide chains called short chain chains are held by disulphide bridges constant region variable region
49
how do antibodies defend body
1) antibody of antigen-antibody complex acts as opsonin so complex is easily engulfed by phagocytes 2) antibodies act as agglutinins causing pathogens carrying antigen-antibody complex to clump together so phagocytes can engulf at once 3) antibodies act as anti toxins binding to toxins making them harmless
50
where are t lymphocytes made
thymus gland
51
where are b lymphocytes made
bone marrow
52
what do t -helper cells do
produce interleukins which are cytokines stimulates activity of b cells increasing antibody production , stimulates macrophages to ingest pathogens
53
what do t killer cells do
destroy pathogen carrying the antigen produce perforin which kills pathogen by making holes in cell membrane so is freely permeable
54
what do t memory cells
divide rapidly to form t killer cells when antigen comes a second time
55
what do plasma cells
b lymphocyte produce antibodies
56
b effector cells
divide to form plasma cell clones
57
what do b memory cells
remembers particular anitgen to make a rapid response
58
what is natural active immunity
body meets pathogen and creates antibodies and memory cells
59
what is natural passive immunity
body does not make its own antibodies baby receives antibodies by mother by mothers milk
60
what is artificial immunity
antibodies created in one individual then extracted and injected into another temporary immunity
61
what is artificial active immunity
immune system of body is stimulated to make its own antibodies to a safe form of an antigen like a vaccine
62
what is a pandemic
when same communicable disease spreads across a number of countries
63
what is an epidemic
when a communicable disease spreads rapidly to a lot of people at a national level
64
what diseases cant be prevented by vaccines
HIV malaria

biology (17 decks)

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