communicable disease Flashcards

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1
Q

name for the 4 types of pathogens

A

bacteria, viruses, fungi and Protoctista

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2
Q

give some information on bacteria

A

they are classified based on shape and/or cell wall
no membrane bound organelles
prokaryotes

produces toxins that poison/damage host cells. can break down the cell membrane, inactivate enzymes or interact with genetic information and prevent cell division.

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3
Q

give some information on viruses

A

0.02-0.3um
non living agent
DNA or RNA surrounded by a protein.
reproduce rapidly and take of the biochemistry of the host cell.
good at developing adaptations to treatments
can attack bacteria forming bacteriophages
ULTIMATE PARASITE

take over the cell metabolism and genetic information. then reproduces rapidly. cell bursts open and spread to other cells to cause infection.

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4
Q

give some information on Protoctista

A

eukaryotes
single or multi cellular
disease causing Protoctista use animals as a host and require a vector to transfer them

digest and use cell component to reproduce.

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5
Q

give some information on

A

eukaryotes
multicellular
can PHS and digest food extracellularly
saprophytes - feed on dead matter
when they reproduce the make millions of spores which can spread far and rapidly.

digest living cells, destroying them. can also release toxins.

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6
Q

explain a type of staining that enable you to identify the type of cell wall in a prokaryote

A

Gram staining
gram positive - purple/blue under the microscope. ie MRSA
gram negative - red under the microscope ie e.coli

this is useful because it indicates which antibiotics will be most effective when reacting with the pathogen based on the cell wall.

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7
Q

what is a communicable disease

A

caused by pathogens and can be passed on from one organism to another causing disease.

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8
Q

give an example of a bacteria disease in plants

A

ring rot
gram positive bacteria
affects potatoes and tomato’s
effects the entire field so it cannot be used to grow crops for at least 2 years after the infection.

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9
Q

give an example of a viral disease in plants

A

TMV (Tobacco mosaic virus)
affects tomatoes and peppers
stunts growth and reduces yield
no cure but resistant crop stains are available

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10
Q

give an example of a Protoctista disease in plants

A

potato blight
cell body penetrates the host cell, destroying leaves.
no cure but resistant strains and careful management of chemical treatments can reduce infection

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11
Q

give an example of a fungal disease in plants

A

black sigatoka
bananas
cell body penetrates and digests leaves and cells causing them to turn black.
resistant strains are being developed.
no cure but fungicide treatment can reduce the spread.

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12
Q

give an example of a bacteria disease in animals (2)

A

tuberculosis TB
humans, cows, badgers and pigs
damages and destroys lung tissue supressing the immune system so less able to fight off infection.
curable by antibiotics and preventable by improved living conditions

meningitis
attacks the protective membranes in the brain
can spread to other parts of the body causing blood poisoning
effects mostly young children and teenagers
glass test - red, purple rash that will not disappear when pressure is applied.
vaccines and antibiotics if caught early enough are used as treatments

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13
Q

give two examples of viral diseases

A

HIV AIDS targets T helper cells in the immune system so people are open to other infections
it is a retrovirus with RNA which transcribes into a single strand of DNA invading the host cell genetic material.
passed from person to person through bodily fluids ie sex, exchange of needles, some unsterile medical practices, mother to baby during breast feeding.
no vaccine and no cure but anti retroviral drugs can slow down the progress of the disease.

influenza effects the ciliated epithelial cells in gas exchange system. it kills them leaving the airways open to secondary infection. can be fatal in young, old and vulnerable people. having the flu one year will leave you with immunity for the next due to the small changes of the antigens on the plasma membrane. occasionally there will be big changes on the surface of the virus which will lead to an epidemic/pandemic as there are no antibodies available.

Zootonic influenza is caught from animals.

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14
Q

give one protocitista disease

A

malaria - spreads through the bite of a female mosquito (Anopheles) when feeding on humans for blood caused by the pathogen Plasmodium it can invade RBC, liver and the brain. the disease makes people weak and vulnerable to other infections
no vaccine and limited cures but preventative measures can be effective.
using mosquito nets, insecticides, removing standing water, long sleeve clothes and keeping doors and windows shut.

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15
Q

how do you identify pathogens

A
  • pathogens are cultured in the lab and identified with a microscope
    -monoclonal antibodies can be used to identity
  • DNA sequencing technology means pathogens can be identified down to a single mutation.
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16
Q

how do you identify pathogens

A
  • pathogens are cultured in the lab and identified with a microscope
    -monoclonal antibodies can be used to identity
  • DNA sequencing technology means pathogens can be identified down to a single mutation.
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17
Q

give three direct ways that pathogens can be spread in animals

A

direct contant ie kissing, touching, transmitting faeces on hands
inoculation (break of the skin) ie sex, animal bite or puncture wounds (through sharing needles)
ingestions ie contaminated food or drink

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18
Q

give 3 examples of how pathogens can be indirectly transmitted

A

fomites inanimate objects sich as bedding and socks ie athletes foot

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19
Q

give 3 examples of how pathogens can be indirectly transmitted

A

fomites inanimate objects sich as bedding and socks ie athletes foot
droplet saliva and droplets are expelled from your mouth as you talk.
vectors transferred pathogen to a host
water can also be a vector

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20
Q

give 2 fungal diseases

A

ring worm and athletes foot

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21
Q

how are pathogens transmitted between plants

A

direct contact with unhealthy plant
soil contamination left behind by infected crops can often effect the next crop.
vectors ie the wind, water splashes, animals and humans

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22
Q

what factors affect the spread of disease in plants

A

planting varieties of crops that are susceptible to disease, overcrowding, poor mineral nutrition, damp and warm conditions and climate change (increase rain fall and wind which promotes the spread to new areas).

23
Q

how do plants defend themselves against an attack

A

receptors in the cell wall respond to molecules that are from the pathogen or chemicals produced during the attack. genes in the nucleus are switched on and defence is initiated.
- callose (1-3 and 1-6 beta linkage) is synthesised and deposited between cell walls in the cell next to be infected, the plasmadesmarta and seive plates. this acts as a barrier preventing the infection from spreading
-lignin is also added to strengthen the cell wall

there is also a range of chemical defences

24
Q

name the chemical that has a bitter rase, noxious smell and poisonous characteristics. and give an example of a plant that uses this

A

alkaloids - it can deter/kill herbivores ie tobacco -> nicotine as a response to tissue damage which is poisonous to many insects

25
Q

what does the chemical tannins do in plants

A

tastes bitter, can bind to proteins in the gut of herbivores such as cattle and make it hard for them to digest so they are less likely to eat it

26
Q

what do pheromones do it corn plants

A

attracts parasitic wasps which kills caterpillar eating the plant by laying eggs on it.

27
Q

outline the components of the non specific immune system

A

blood clotting
inflammatory response
fever
phagocytosis

28
Q

how does the body keep pathogens out

A

skin contains sebum which prevents them from growing and lots of healthy microorganisms which outcompetes them for space.
mucous membranes in air ways and nose to prevent pathogens entering
lysozymes in tears and urine as well as acid in the stomach
expulsion reflexes ie coughing and sneezing and diahorria and vomitting

29
Q

describe blooding clotting process

A

thromboplastin - triggers a cascade of reactions when platelets come in contact with collagen in the skin.
thromboplastin and Ca2+ catalyses the react of prothrombin to thrombin.
thrombin catalyses the reaction of fibrinogen to fibrin which forms a clot.

a scab forms to keep pathogens out, epidermal cells below the scab grow sealing the wound permanently.

29
Q

describe blooding clotting process

A

thromboplastin - triggers a cascade of reactions when platelets come in contact with collagen in the skin.
thromboplastin and Ca2+ catalyses the react of prothrombin to thrombin.
thrombin catalyses the reaction of fibrinogen to fibrin which forms a clot.

30
Q

what role does serotonin play in blood clotting

A

makes smooth muscle contract so they are narrow and reduce the supply of blood to the area

31
Q

describe the inflammatory response

A

associated with heat (prevents the pathogen from reproducing), swelling, redness and pain.
mast cells are activated in damaged tissue which release
-histamines which cause the vessels to dilate (causing swelling) and walls become more leaky so blood plasma is forced out and as a result tissue fluid is left behind.
- cytokines attract WBC to the site

31
Q

describe the inflammatory response

A

associated with heat (prevents the pathogen from reproducing), swelling, redness and pain.
mast cells are activated in damaged tissue which release
-histamines which cause the vessels to dilate (causing swelling) and walls become more leaky so blood plasma is forced out and as a result tissue fluid is left behind.
- cytokines attract WBC to the site

32
Q

how do fevers get rid of pathogens

A

cytokines stimulate the hypothalamus to rest its thermostat to above 37 degrees to inhibit pathogen reproduction and increase the rate of the specific immune system works.

33
Q

describe phagocytosis

A

WBC that engulf and destroy pathogens. neutrophils and macrophages. (pus contains dead WBC)

they recognise the pathogen as non self and attack the pathogen. they engulf forming a PHAGOSOME. which combines with a lysosome to form PHAGOLYSOSOME. the LYSOSOME digest and destroy pathogens

34
Q

How do APC form

A

only macrophages
once it has digested a pathogen it combines with antigens from the pathogens membrane. it requires special glycoproteins in the cytoplasm to form hristocompatabile complexes which one to the macrophages cell surface membrane becoming an APC.

35
Q

what do opsonins do

A

they bind to pathogen and tag them they are more easily recognised. means phagocytes can bind with more then one pathogen at once.

36
Q

what do opsonins do

A

they bind to pathogen and tag them they are more easily recognised. means phagocytes can bind with more then one pathogen at once.

37
Q

outline the components of the specific immune system

A

antibodies
lymphocytes
cell mediated immunity
humeral immunity

38
Q

what is an example of when the specific immune system goes wrong

A

an autoimmune disease. when the self cells start to attack the healthy body tissue. (sometimes because the T regulatory cells do not work effectively)
treatment can be immunosuppressant drugs which prevent the immune system working but then increase the susceptibility to other infections

examples are type 1 diabetes, arthritis and lupus (skin and joints and causes fatigue)

39
Q

how do antibodies defend the body against pathogens

A

tag pathogens so that they are more easily identified by WBC.
once they bind with pathogens they can no longer invade other cells
agglutinins causing the pathogen and antigen complex to clump together so more than one can be engulfed at the same time.

40
Q

where are T lymphocytes made

A

thymus gland

41
Q

where are B lymphocytes made

A

bone marrow

42
Q

what do Thelper cells do

A

bind to APC
produce interleukins (which stimulates B cells and other types of t cells)

43
Q

what do t killer cells do

A

they produce a chemical called perforin which kills the pathogen by making holes in its cell surface membrane.

44
Q

what do t memory cells do

A

live for a long time. if they meet the same antigen, they divide rapidly into t killer cells destroying the pathogen.

45
Q

what do t regulatory cells do

A

suppress the immune system once the pathogen has been eliminated.

46
Q

there are three types of B cells name them and their role

A

plasma cells - produce antibodies and release into the blood to increase phagocytosis
B effector - divide into plasma cells
b memory - remember an antigen if it returns, rapid cloning to eliminate it. providing immunological memory

47
Q

outline the cell mediated immunity response

A

APC collide with T helper cells with the same receptors. this activates the t helper cells and causes interleukins to be produced - stimulating more T helper cells to divide rapidly by mitosis. the t helper cell clones can develop into
T memory cells
interleukins - phagocytosis
interleukins - b cells divide
t killer cells

48
Q

what is humoral immunity

A

response to antigens found outside cells. produces antibodies that are soluble in the blood. not attached to cells

49
Q

describe the humoral immune response

A

b cells contain receptors that ate complimentary to only one type of antigen, when the antigen is present it will bind and activate clonal expansion.

50
Q

what is clonal selection

A

this is the process in which the complimentary B cells are activated. it begins with a macrophage which undergoes histocompatibility to become and antigen presenting cell. the APC binds with the complimentary T helper cell which divides by mitosis into more T cells and cytokines (to increase phagocytosis) or releases interleukins which cause B cells to be secreted.

51
Q

why may someone who has had a disease lose immunity after a period of time has passed.

A

B memory cells may die
no secondary response
no repeated infections

52
Q

What feature of a pathogen such as Mycobacterium tuberculosis could be altered by a mutation, making a vaccine ineffective?

A

antigens on the plasma membrane