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

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    For this exam, do we need to know the structure of the eye? or just about rod and cone cells and acuity/sensitivity ect?
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    Bio stinks!
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    (Original post by Aishie)
    loool i knowww i did too
    i know its a probably been said..but stupid aqa
    btw how are you revising for the essay?
    im majorly panicking about the essay as we speak haha, desperately searching the net for example essays to help me i have printed off a copy of each of the past specs + will probably just work my way through them + see how much i can actually remember! (which wont be alot)
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    How does siRNA work?

    i really don't understand how it is double stranded if it is made by cutting up RNA with an enzyme, because RNA is single stranded..
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    (Original post by vickidougal)
    How does siRNA work?

    i really don't understand how it is double stranded if it is made by cutting up RNA with an enzyme, because RNA is single stranded..
    not necessarily....if u look at tRNA some of the places have base pairs....and it does say in the book that RNA can bind to each other.
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    because the siRNA are a special type of RNA that are double stranded and they can unzip to become single stranded. They then get attached to an enzyme which has the ability to cut the mRNA into small sections so that it cannot be translated.

    ps. my biology teacher said that siRNA are very new discoveries and so it defies the original belief that RNA's are always single stranded.
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    For question 1 in the chapter 9 questions (text book)
    part b, the answer is stays longer in warmer area / at 35° / tends to leave cooler area / to leave 30° / stays in favourable conditions; remains near food source / on host;
    But in the text book, when it does more turns in kinesis, it is more likely to move into a new area .. so wouldn't the 35 C condition be the unfavourable one? I don't get it :/ the question answer makes sense too though
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    (Original post by belle-a)
    because the siRNA are a special type of RNA that are double stranded and they can unzip to become single stranded. They then get attached to an enzyme which has the ability to cut the mRNA into small sections so that it cannot be translated.

    ps. my biology teacher said that siRNA are very new discoveries and so it defies the original belief that RNA's are always single stranded.
    Enzyme is called RISC (RNA induced silencing complex), that might be helpful if the essay is on enzymes/proteins
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    (Original post by atofu)
    For question 1 in the chapter 9 questions (text book)
    part b, the answer is stays longer in warmer area / at 35° / tends to leave cooler area / to leave 30° / stays in favourable conditions; remains near food source / on host;
    But in the text book, when it does more turns in kinesis, it is more likely to move into a new area .. so wouldn't the 35 C condition be the unfavourable one? I don't get it :/ the question answer makes sense too though
    The more turns it does the more likely it is not to move out of the place it's in. It's when it does less turns and moves a greater distance that it is more likely to leave where it is.
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    what is the difference between a generator potential and an action potential ?! (sorry if this sounds reaally stupid)
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    (Original post by vickidougal)
    what is the difference between a generator potential and an action potential ?! (sorry if this sounds reaally stupid)
    A generator potential happens when the energy from the stimulus is "tranduced" by the receptors to a nerve impulse.
    An action potential is created from a generator potential if it exceeds the threshold level.
    Generator potential does not travel along the axon, the action potential does.
    I think!
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    (Original post by vickidougal)
    what is the difference between a generator potential and an action potential ?! (sorry if this sounds reaally stupid)
    As I understand it (and anyone feel free to correct me) a generator potential is a build up of depolarisation caused by the initial stimulus (i.e. light). If the generator potential reaches the threshold value then an action potential is created and transmitted along neurones.
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    (Original post by atofu)
    For question 1 in the chapter 9 questions (text book)
    part b, the answer is stays longer in warmer area / at 35° / tends to leave cooler area / to leave 30° / stays in favourable conditions; remains near food source / on host;
    But in the text book, when it does more turns in kinesis, it is more likely to move into a new area .. so wouldn't the 35 C condition be the unfavourable one? I don't get it :/ the question answer makes sense too though
    tbh both are wrong
    in klinokinesis, which is a random movement in which the rate of turning is related to the intensity of the stimulus, the greater the rate of turning, the more likely it is that the organism will remain in the area.
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    (Original post by cws121)
    Do we have to know about the CFTR and cystic fibrosis in gene therapy? Its not in the spec but theres a whole chapter on it in the book...? i dont wanna be learning something we dont have to know!! thanks
    I've seen past questions on CFTR but they were from the old papers

    and spec says "Candidates should be able to evaluate the effectiveness of gene therapy.", if they ask about treating cystic fibrosis you should probably know how it is defective in the first place im guessing?? not sure though!!
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    (Original post by indifferencepersonified)
    The more turns it does the more likely it is not to move out of the place it's in. It's when it does less turns and moves a greater distance that it is more likely to leave where it is.
    Ah kk, thanks


    (Original post by Flux_Pav)
    tbh both are wrong
    in klinokinesis, which is a random movement in which the rate of turning is related to the intensity of the stimulus, the greater the rate of turning, the more likely it is that the organism will remain in the area.
    thanks, this makes sense too
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    (Original post by Pixiefairy)
    i have over 20 essays and analysis on them if anyone wants i can email it to them
    please could you email it to me as well, getting really nervous abt essays..
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    (Original post by al_habib)
    please could you email it to me as well, getting really nervous abt essays..
    and me please
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    (Original post by vickidougal)
    and me please
    and me. . .
    I couldn't find where the original post was!
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    (Original post by indifferencepersonified)
    and me. . .
    I couldn't find where the original post was!
    care to pass this on please?
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    (Original post by hey_its_nay)
    care to pass this on please?
    brah! send it to me when you get it. Cheers.
 
 
 
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