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    go on the aqa website the list of essays is there
    i think theres a list on google (sorry id look it up for you but currently going of electrophoresis and dna fingerprinting haha!
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    Hi, could anyone list how heat is lost via each temp control mechanism? For example which ones are conduction, radiation etc. I would be forever grateful!
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    is anyone able to explain to me the movement of an action potential in an unmyelinated axon? the textbook (pg 169) is ridiculously confusing
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    Anyone have a list of topics that didn't come up last year? would greatly appreciate it
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    (Original post by triplet3)
    I was just thinking theres not much unit 1/2 things you could talk about with an ions essay though...all I can think of is sodiums role in glucose absorption, and the role of potassium/salt in oral rehydration therapy to treat Cholera.
    (If this came up as an essay I would be so happy though!!)
    I guess you could include a quick short para on Iron ions, haemoglobin, if you wanted to reference all units
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    what time is the exam?
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    (Original post by studentwiz)
    what time is the exam?
    9am ^_^ , but I'm slightly worried you're asking this now lol
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    (Original post by charlottei)
    Hi, could anyone list how heat is lost via each temp control mechanism? For example which ones are conduction, radiation etc. I would be forever grateful!
    Vasoconstriction, sweating/panting (evaporation), lowering of hair = heat is lost via conduction/convection
    Thats all you need to know
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    (Original post by mck9777)
    I guess you could include a quick short para on Iron ions, haemoglobin, if you wanted to reference all units
    Good point - also would it be relevant to talk about ions in terms of being part of structures e.g proteins/carbohydrates??
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    (Original post by Vengefulcandy)
    Vasoconstriction, sweating/panting (evaporation), lowering of hair = heat is lost via conduction/convection
    Thats all you need to know
    Are all three both conduction AND convection? :/
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    I am so ducked
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    (Original post by charlottei)
    Hi, could anyone list how heat is lost via each temp control mechanism? For example which ones are conduction, radiation etc. I would be forever grateful!
    (Original post by Vengefulcandy)
    Vasoconstriction, sweating/panting (evaporation), lowering of hair = heat is lost via conduction/convection
    Thats all you need to know
    You could mention radiation as I have seen it in a couple of questions I have done.

    So for heat loss: Vasodilation of the arteriole walls would lead to more radiation of heat and so there will be more heat lost from the blood.
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    (Original post by kiwi8397)
    is anyone able to explain to me the movement of an action potential in an unmyelinated axon? the textbook (pg 169) is ridiculously confusing
    (I'm going to assume you know how an AP starts)

    So after an AP occurs, the local depolarisation is detected by other voltage-gated ion channels further along the axon. So more Na+ ions diffuse in further along and another depolarisation occurs, so another AP. An AP will always move along the neurone and never backwards because, the previously depolarised region has entered a refractory period (ion channels closed) and becomes hyperpolarised. So only downstream ion channels can open, therefore AP can only go forward.

    In short:

    1. Other voltage-gated ion channels detect depolarisation and so open
    2. Na+ ions diffuse in and so another AP generated
    3. AP only goes forward because previous region is in refractory period
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    In terms of homoeostasis, what does the spec mean when it says internal conditions are controlled within certain limits?
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    desperately need essay predictions (maybe given by teachers) to narrow workload
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    (Original post by Monkey D. Luffy)
    You could mention radiation as I have seen it in a couple of questions I have done.

    So for heat loss: Vasodilation of the arteriole walls would lead to more radiation of heat and so there will be more heat lost from the blood.
    Don't say radiation, it said accept conduction/convection in the mark scheme but reject radiation. Don't know why but its aqa biology for you
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    (Original post by Hollyh12345)
    Can someone give me a List of random essays they've come up with so I can practice planning essays?
    Membranes and functions
    Relationships and interactions between organisms
    Importance of shapes fitting together in cells and organisms
    Effects of bacteria on the lives of humans and other organisms
    DNA in science and technology
    Causes of disease in humans
    Biological cycles
    Ions and organisms
    DNA and transfer of information
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    Does anyone know of any essays that commonly come up or any topics that are crucial for essays?
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    (Original post by Vengefulcandy)
    Don't say radiation, it said accept conduction/convection in the mark scheme but reject radiation. Don't know why but its aqa biology for you
    We may have seen similar questions. The one I saw had radiation specifically on the mark scheme. There was no sign of conduction/radiation.
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    (Original post by sodaman96)
    In terms of homoeostasis, what does the spec mean when it says internal conditions are controlled within certain limits?
    Guess it just means that the body can cope with slight changes in temperature etc but not with extremes
    for example if it was too cold, you would freeze to death
 
 
 
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