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    (Original post by bubblegummer)
    Yeap you are correct. Rhodopsin reforms at a faster rate in dark adaptation
    Thank you
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    Hello, anyone know the topics that might come up in the advance article section?
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    (Original post by Mallika)
    I don't think we need anymore detail than what dark/light adaptation actually is but better safe than sorry :P
    True
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    The official Edexcel textbook is so crap it actually annoys me
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    (Original post by jojo1995)
    thank you

    im doing normal edexcel, do i need to know the stuff about a and d and b and co? .... you explained it well its just alot to get my head around
    Nope, you don't
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    (Original post by nukethemaly)
    The official Edexcel textbook is so crap it actually annoys me
    What? I think it's great.
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    would be really grateful if someone could explain the stages of anaerobic respiration :s its not very clear in my textbook and the mark schemes don't really help ssince they dont connect the stages
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    Could someone give details on the core practicals in the spec:
    1. Describe how to investigate rate of respiration practically. (6)
    2. Describe how to investigate the effects of exercise on tidal volume and breathing rate using data from spirometer traces. (14)
    3. Describe how to investigate habituation to a stimulus. (15)
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    (Original post by SKK94)
    Nope, you don't
    thank you
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    (Original post by nukethemaly)
    The official Edexcel textbook is so crap it actually annoys me
    SNAB is no better trust me. Doesn't help that the site is down as well
    2.30pm on Monday I will be the happiest girl alive at that moment :cool:
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    (Original post by p1234h)
    would be really grateful if someone could explain the stages of anaerobic respiration :s its not very clear in my textbook and the mark schemes don't really help ssince they dont connect the stages

    In anaerobic respiration basically it occurs due to the lack of oxygen in our muscles. energy is needed for the contration of the muscle so small amounts of ATP is released.

    To know how this happens
    - initially pyruvate is converted to lactate
    - the conversion causes reduced NAD to be oxidised to NAD
    - NAD is regenerated so that more ATP can be produced from glycolysis
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    (Original post by nukethemaly)
    The official Edexcel textbook is so crap it actually annoys me
    :O Really? The SNAB one? What don't you like about it? I think it's quite good


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    (Original post by super121)
    :O Really? What don't you like about it? I think it's quite good


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    How science works Is a load of tosh, to much irrelevant garbage which isn't the syllabus and it isn't wrote in a concise way. For those reasons I personally use the revision guide and supplement my knowledge with points from mark schemes from past papers.
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    The problem with biology is the mark schemes can be so specific. I never know when I mark my own past papers whether the examiners will accept something like "thus more blood is pumped out of heart" when it says on the mark scheme "so there is increased cardiac output". Do you think in a circumstance like that the mark would be awarded?
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    (Original post by iwantopas19)
    in darkness there is more far red light than red light. therefore PFR is converted to PR. to maintain the equilibirum.
    Hi - couple of corrections here:

    Far red light does not really exist in usual conditions. The Pfr is converted into Pr by long periods of darkness - slowly, so the proportions change with the length of darkness. It is more or less instantly converted to Pfr - so it is uninterrupted periods of darkness that are needed. There was some experiment where a light was flashed on every two hours in a 14 hour stretch of darkness and the Pfr proportion did not reduce significantly.

    (Original post by iwantopas19)
    yeah u are right PR is inactive it inhibits flowering whereas PFR is active and causes germination and flowring
    The Pfr is ALWAYS the active one - as a stimulator or as an inhibitor. The Pr being inactive does not mean it in inhibits. In short day plants for example Pfr inhibits flowering - only when lots of it has been converted to Pr do the plants flower - i.e. when the nights are long. In long day plants it stimulates flowering.
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    How many of the article marks /30 would you say were comprehension?

    Thanks
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    (Original post by super121)
    :O Really? The SNAB one? What don't you like about it? I think it's quite good


    Posted from TSR Mobile
    It's too long and packed with uselessness.

    I mainly use the CGP and the official snab revision guide, though I do refer back to the big book for the larger chapters.
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    (Original post by Lgambo)
    The problem with biology is the mark schemes can be so specific. I never know when I mark my own past papers whether the examiners will accept something like "thus more blood is pumped out of heart" when it says on the mark scheme "so there is increased cardiac output". Do you think in a circumstance like that the mark would be awarded?
    Usually equivalents next to most points on the mark scheme but its up to the examiner whether they want to award you the mark penultimately. Id defo analyase past mark schemes and use the specific terminology they contain.
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    (Original post by bubblegummer)
    In anaerobic respiration basically it occurs due to the lack of oxygen in our muscles. energy is needed for the contration of the muscle so small amounts of ATP is released.

    To know how this happens
    - initially pyruvate is converted to lactate
    - the conversion causes reduced NAD to be oxidised to NAD
    - NAD is regenerated so that more ATP can be produced from glycolysis
    thank you! afterwards, when lactate is taken to the liver to be converted back to pyruvate... why does the livers oxygen demand increase?
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    (Original post by p1234h)
    thank you! afterwards, when lactate is taken to the liver to be converted back to pyruvate... why does the livers oxygen demand increase?
    Because:
    -Lactate needs to be converted into pyruvate by oxidation
    -The lactate is oxidised by the Krebs cycle to give pruyate, C02 and H20
    -The extra oxygen needed for this process is called the oxygen debt
 
 
 
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