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AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011 watch

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    (Original post by Carpet21)
    The book doesn't really tell us much about troponin does it?
    it is just a molecule which has a calcium binding site, when calcium is there it causes the tropomysoin to move.
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    (Original post by mrt23498)
    Does anyone have the exam style question answers for unit 5 questions at the end of the book of the nelson thornes book?


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    (Original post by Carpet21)
    The book doesn't really tell us much about troponin does it?
    Not quite sure which book you mean, but all you need to know if that it holds tropomyosin in place, tropomyosin blocks the actin-mysosin binding site so the myosin globular head cannot bind = muscle contraction cannot happen.

    For muscle contraction to happen, calcium ions must bind to troponin and thus induce it to change its shape, which moves tropomyosin from thr actin-myosin bindign site, so cross bridges can form, and muscle contraction can happen.

    When calcium ions leave troponin, it changes back to original shape, and so tropomyosin blocks the actin-myosin binding site again, stopping muscle contraction.
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    (Original post by oloyeded020)
    do we need to know about water potential control with ADH etc

    anyone?
    Its not on the spec and I had to google it to find out what it is...still not sure, is it a hormone?

    I'd pressume we don't need to know it, nobody has mentioned it and its not in the CGP guide or my textbook.
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    (Original post by aj2010)
    I REALLY don't unterstand sanger method and restriction mapping. can someone explain pleasseeeee;

    and also what's the difference between adenovirus and retrovirus
    Adenovirus: Any of a group of DNA viruses first discovered in adenoid tissue, most of which cause respiratory diseases.

    Retrovirus: Any RNA virus that inserts a DNA copy of its genome into the host cell in order to replicate, e.g., HIV
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    any ideas for essay questions? i reckon it could be on cycles
    hows everyone revising for the essay? ive done 2 but only got 15/25 on them even after doing everything my teacher said to improve ha! have to get all my marks from the exam as im bad at essays!
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    (Original post by User12399)
    it is just a molecule which has a calcium binding site, when calcium is there it causes the tropomysoin to move.

    (Original post by Tericon)
    Not quite sure which book you mean, but all you need to know if that it holds tropomyosin in place, tropomyosin blocks the actin-mysosin binding site so the myosin globular head cannot bind = muscle contraction cannot happen.

    For muscle contraction to happen, calcium ions must bind to troponin and thus induce it to change its shape, which moves tropomyosin from thr actin-myosin bindign site, so cross bridges can form, and muscle contraction can happen.

    When calcium ions leave troponin, it changes back to original shape, and so tropomyosin blocks the actin-myosin binding site again, stopping muscle contraction.
    I can't find that at all in the Toole and Toole book! But thank you that makes sense.
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    (Original post by empop92)
    any ideas for essay questions? i reckon it could be on cycles
    hows everyone revising for the essay? ive done 2 but only got 15/25 on them even after doing everything my teacher said to improve ha! have to get all my marks from the exam as im bad at essays!
    If it is cycles I would love it! My teacher made us do about 5 essays, which is good

    Cycles from Unit 1 and 2?
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    I'm hoping Muscle Contraction, Eyes, Making DNA and Glucose comes up!
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    Do we need to just be aware of Histamine and Prostoglandin? Or do we need to know what they do?
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    :charm:
    (Original post by NRican)

    thank you
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    (Original post by Tericon)
    Both secreted by the Islets of Langerhans in the pancreas, both hormones.

    Insulin secreted by beta cells in Islets, Glucagon by alpha cells in Islets.

    Insulin is secreted when blood glucose concentration is too high.

    Functions:

    Activates enzymes for glycogenesis = converts glucose into glycogen.

    Increases rate of respiration of glucose in cells

    Makes cells more permeable to glucose.

    Glucagon, secreted when blood glucose concentration is too low

    Functions:

    Activates enzymes for glycolysis = conversion of glycogen into glucose

    Decreases rate of respiration of glucose

    Stimulates gluconeogenesis = production of glucose from non-carbohydrates, such as amino acids for example.
    Glycolysis is the first stage of respiration (glucose->pyruvate) glucagon activates glycogenolysis (glycogen->glucose) .
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    (Original post by M | k e)
    Glycolysis is the first stage of respiration (glucose->pyruvate) glucagon activates glycogenolysis (glycogen->glucose) .
    Damnit, I was trying to learn how to spell those properly the other night...I obviously failed. Thanks
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    (Original post by mrt23498)
    So you have so far 400 UMS, you need 480 for A, hence you need 80/140 UMS marks,
    For A* you need 148/140 UMS hence impossible
    Just wondering, I though for A* you had to get over 90 ums in unit 4, over 126 ums in unit 5 and an A in As?
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    (Original post by NRican)
    around 120 UMS
    thats very high i thought it wuld be lwer than that lol
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    (Original post by Tericon)
    Do we need to just be aware of Histamine and Prostoglandin? Or do we need to know what they do?
    just be aware of what they do.

    Histamine: Released when allergen enters body, swelling, redness incheness.
    Prostoglandin: released when you are injured, increases permeability of capallieires.
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    (Original post by User12399)
    just be aware of what they do.

    Histamine: Released when allergen enters body, swelling, redness incheness.
    Prostoglandin: released when you are injured, increases permeability of capallieires.
    Thanks
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    (Original post by User12399)
    just be aware of what they do.

    Histamine: Released when allergen enters body, swelling, redness incheness.
    Prostoglandin: released when you are injured, increases permeability of capallieires.
    Is it not the other way round?
    I thought Histamine increase permeability to immune cells near to an injury/infection. And Prostaglandins was repsonsible for swelling immflamation etc
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    for those of you still worried about the essay question i just found this site which is worth checking out
    gives great info on what to expect, how to structure your answers and what to focus on/ how to plan

    http://www.studentcreche.co.uk/showt...y-Student-Pack
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    (Original post by Stirlo)
    Is it not the other way round?
    Histamines must be released when allergens enter the body as allergy medication contains 'antihistamines'.

    They both contribute to the inflammatory response however.

    Histamines = released in response to injury or infection, increases permeability of capillaries to allow more immune system cells to diffuse out of blood to infected or injured area.

    Prostaglandins = involved in inflammation, fever, blood pressure regulation and blood clotting. Different types however, one is released by blood vessel epithelium cells and causes muscles around them to relax.
 
 
 
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