b6.3 - immune system Flashcards

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1
Q

ELISA test

A

sees if plant contains pathogen antigen

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2
Q

ELISA test method

A
  • obtain + liquidise sample put into a plastic tube
  • wash to wash off any proteins not bound to plastic
  • add a blocking agent to block all plastic that has not been covered with protein
  • wash again to revive unbound blocking agent
  • add antibody enzyme complex that is specific to pathogens antigen
  • wash again to remove unbound antibody enzyme complex
  • add colourless substrate that the enzyme changes into a coloured product
  • if pathogen is present it’ll change colour
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3
Q

primary immune defences

A
  • skin
  • mucous membranes
  • blood clots
  • respiratory surfaces
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4
Q

skin

A

keratin layer , epidermis, sweat gland, hair follicle, dermis, subcutaneous layer
- waterproof barrier that prevents pathogens from entering

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5
Q

commensalism bacteri

A

not harmful bacteria on the skin surface
- outcompete any pathogenic bacteria and fungi that may land on the skins surface

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6
Q

mucous membranes

A

nasal muscles traps air borne organisms
any that get past get trapped in the respiratory tract
- mucus is produced by goblet cells
- and is removed by cilia beating passing it to stomach where high acidity denatures it
- contains LYSOZYME which is an antibiotic and destroys pathogens

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7
Q

blood clots

A
  • when skin is cute platelets are exposed to air
  • cause a protein called FIBRINOGEN to change to fibrin (insoluble)
  • fibrin forms a mesh over wound
  • red blood cells are caught in the mesh - platelets stick together - form blood clots
  • clot hardens to a scab keeping skin clean with time to heal
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8
Q

respiratory surfaces

A
  • mucus secreted by goblet cells trap dust particles and microbes
  • cilia beat and waft the mucus up to the top of the throat when swallowed
  • cilia contain many mitochondria to supply the energy needed
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9
Q

types of white blood cells

A
  • lymphocytes
  • phagocytes
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10
Q

lymphocytes

A
  • produce antibodies that destroy pathogens - some provide immunity
  • similar size to red blood cells with a spherical nucleus
  • 25% of white blood cells
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11
Q

phagocytes

A
  • engulf bacteria and other microorganisms
    (phagocytosis)
  • encloses bacteria in phagosome and digestive enzyme released to destroy bacteria
  • relatively large cells, often with lobed nucleus (to allow it to engulf pathogens)
  • ## 70% of white blood cells
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12
Q

antigens

A
  • protein on the cell membrane of pathogens
  • each pathogen has uniquely shaped antigens
  • some pathogens (eg flu) may alter antigens yearly
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13
Q

antibodies

A
  • are proteins made by lymphocytes
  • have specific shape (3D) complementary to a specific antigen
  • antibodies bind to antigens on the surface of pathogens
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14
Q

how lymphocytes bind to antigens

A
  • each lymphocyte has antibodies specific to antigens
  • when an antigen is in the blood a lymphocyte with complementary receptor will be found and will bind to it
  • the appropriate lymphocyte then divides by mitosis
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15
Q

antibody structure

A

see diagram
- antigen binding site
- constant regions
- heavy chains
- light chains
- hinge
- variable parts ( change from antibody to antibody but dont change once its made)

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16
Q

how antibodies kill pathogens

A

cell lysis
agglutination
neutralisation

17
Q

how antibodies kill pathogens - cell lysis

A
  • may cause pathogens to burst open rendering them unable to infect our cells
18
Q

how antibodies kill pathogens - agglutination

A
  • antibodies may bind to a number of pathogens causing them to clump together
  • the group of pathogens is too large to enter a cell and can be destroyed by phagocytes
19
Q

how antibodies kill pathogens - neutralisation

A
  • antibodies cover pathogens and prevent it from binding + entering a host
  • antitoxins released from lymphocytes may also act on toxins released from pathogens rendering them ineffective
20
Q

monoclonal antibodies

A

are specific to one binding site on one antigen - target a specific cell/ chemical

21
Q

how many antibody types does a antigen make

A

one type of antibody specific to one antigen

22
Q

why are lymphocytes combined with other cells to make monoclonal antibodies

A

it cant divide anymore so if we want lots of antibodies we need a cells that will divide

23
Q

how to make monoclonal antibodies

A
  • a mouse is infected with a specific antigen to stimulate lymphocytes to make particular antibodies
  • extracted lymphocytes are combined with tumour cells that can divide and make antibodies (hybridoma cells)
  • separated and each cell is cloned making cells that produce the same antibody
  • antibodies are made, collected and purified
24
Q

monoclonal antibodies uses

A
  • for diagnosis
  • in research
  • to treat some diseases
25
Q

monoclonal antibodies uses - for diagnosis

A
  • pregnancy tests - monoclonal antibody binds to hCG in urine
26
Q

monoclonal antibodies uses - in research

A
  • mAB can locate or identify specific molecules in a cell/tissue
  • these have fluorescent tags in them
  • the mABs then bind the specific molecules in the cell
27
Q

monoclonal antibodies uses - treat diseases

A
  • for cancer mABs can be bound to a radioactive substance, a toxic drug/chemical- which stops cells growing or dividing
  • it delivers the substance to cancer cells without harming healthy cells (specifically targeted)
28
Q

concerns with monoclonal antibody uses

A
  • immunes responses occur as they come from mice cells with foreign proteins
  • side effects - chills/fever, itchy rashes, nausea, headaches