Module 4: Section 1- Disease and the Imunne System

what is a disease?
a condition that impairs the nomal functioning of an organism.
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what are the 3 diseases that are caused by bacteria?
tuberculosis (animals, humans), bacterial meningitis (humans), ring rot (potatoes and tomatos)
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what are the 3 diseases that are caused by virus?
HIV/AIDS, influenza(animals, humans), tobacco mosaic virus (plants)
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what are the 3 diseases caused by fungus?
black sigatoka (banana plants), rigworm (cattle), athletes foot (humans)
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what are the 2 diseases caused by protoctist?
potato/tomato late blight, maleria (animals and humans)
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what is direct transmission?
transmitted directly from one organism to another.
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what is indirect transmission?
when a disease is transmitted from one organism to another via an intermediate.
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what are some examples of an intermediate?
air, water, food, another organism(vector).
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what 3 things affect disease transmission?
living conditions, climate and social factors.
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what would overcrowded living conditions do to diease transmission?
increase it.
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maleria needs hot humid countries for ideal contidions for mosquitos, and spores need water to spread so hot and humid environments will increase it.
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social factors?
like good health care, good health education etc
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wha are the 6 factors that prevent infection in humans?
skin, mucous membranes, blood clotting, inflamation, wound repair, expulsive reflexes.
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what physical defences do plants have against pathogens? 1
waxy cuticle provides a physical against pathogens and prevent collection of water which will decrease the risk of infection through water. Surrounded by cell walls=physical barrier.
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what physical defences do plants have against pathogens? 2
they produce callose between cell walls and plasma membranes during times of stress, makes it harder for the pathogens to enter the cell.
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what chemical defenses do plants have?
they produce saponin which desroys the cell membranes of fungi aand other patogens. and produce phytoalexins whic inhibit growth of fungi and other pathogens. and some chemicals to protect them from insects.
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what is found on the surface of a pathogen?
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what do these antigens do?
activate the immune system
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what is the 1st stage of an non specific immune response? 1
a phagocyte recognises the atigens on a pathogen, the cytoplasm in the phagocyte moves around the pathogen engulfing it.....
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part 2
....., the pathogen is now contained in a phagosome, the lysosome fuses with the phagosome and releases the enzymes to break the pathogen down, the phagocyte then presents the pathogens antigens on its surface= antigen-presenting cell.
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what do thephagocytes then activate?
T Lymphocytes
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what does the T lymphocyte do?
their surface is covered with receptors which bind to the antigens presented on the ntigen-presenting cell. when the receptor meets a complementry atigen, this activates the T lymphocyte=clonal selection, then it undergoes clonal expansion.
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what are the different type of T lymphocyte?
T helper (release substances to actiave B lymphocytes) , T killer (attach to and kill cells infected with a virus), T regulatory (supresses the immune responce from other white blood cells)..
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what do B lymphocytes do?
they are covered with antibodies that bind to the antigens to form an antigen-antibody complex. when an antibody binds to a specifc antigen it actvates it=clonal secection, the B lymphocyte divides into plasma, memeory cells= clonal expansion.
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what do plasma cells do?
they secrete loads of antibodies specific to the antigen in the blood.
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what is the structure of an antibody? 1
the variable region are antige bindng sites, the shape of it being complementry to a specific antigen, the hinge region allows felxibility when antibody is binding to the antigen, constant region allow binding to receptors to immune system cells.....
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part 2
the disulfide bridge hold the polypeptide chains of the protein together.
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what do antibodies do to help clear infection? 1
agglutinating pathogens- each antibody has 2 binding sites, it clumps pathpgens togeher, so the phagocytes then bind to them and phagocytose them all at once.
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part 2
Neutralising toxins- anti-toxins can bind to specific antigens and bind to their toxins, preventing them affceting human cells
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part 3
prevents pathogen from binding to a human cell- when antibodies bind to the antigens on the pathogens, they block the cell surface receptors, meaning they cant attach to or infect the host.
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what are the 2 types of immunity?
active and passive
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what is active immunity?
your immune system makes its own antibodies.
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what are the 2 types of active immunity and describe them.
natural- when you become immune after catching a disease. artificial- immmune after being given a vaccination.
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what is passive immunity?
immunity you get from being given antibodies made by a different organism.
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what are the 2 types of passive imunity and describe them.
natural- baby becomes immune due to antibodies from the mother through placenta or breast milk. artificial- after being injected with antibodies from someone else
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what happens in an autoimmune disease?
the immune system doesnt recognise self antigens, it launches an immune response against an organisms own tisses.
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what are some examples of this?
lupus and rheumatoid arthritis
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what is herd immunity?
whe most people in a community are vaccinated, the disease becomes rare, so even people who havent been vaccinated are unlikley to get the disease as there is no one to catch it from.
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what are antibiotics?
chemicals that kill or inhibit growth of bacteria.
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what causes antibiotic resistance?
genetic variations in the bacteria.
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what are some exmaples of antibiotic resistant bacteria?
MRSA -causes serious wound infections and Clostridium difficile- infects digestive system
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what are the 2 ways of trying to over come this?
developing new antibiotics and modifying existing ones, doctors are being encouraged to only to perscribe antibiotics for major infections.
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what are some future medicine?
personalised medicines that are tailored to a persons DNA, and sythetic biology- involves using technolgy yo design and make artificial protens, cells and microorgansims
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Other cards in this set

Card 2


what are the 3 diseases that are caused by bacteria?


tuberculosis (animals, humans), bacterial meningitis (humans), ring rot (potatoes and tomatos)

Card 3


what are the 3 diseases that are caused by virus?


Preview of the front of card 3

Card 4


what are the 3 diseases caused by fungus?


Preview of the front of card 4

Card 5


what are the 2 diseases caused by protoctist?


Preview of the front of card 5
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