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    (Original post by TheLegalDealer)
    So helpful ! Thank you so much ! Btw do we have to learn the raitos or is it better ti work it out ??
    My pleasure ☺️ Yes do learn them as they may get you to identify different types of epistasis.

    Recessive= 9:3:4
    Dominant= 12:3:1 or 13:3
    Complementary= 9:7
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    If you feel at a loss and have basically given up, should you just go on to past papers? Because I feel like I know nothing and maybe if I just do past papers, it'll slowly come to me.
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    Do we need to know the dorsal root ganglia etc in detail ??


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    (Original post by bbadonde2)
    Recessive epistasis is when you need a dominant allele of the epistatic first gene for the second hypostatic gene to be expressed. For example. Coat colour is controlled by the genes Z/z and G/g. For G/g gene to be expressed there must be a dominant allele for the Z/z gene.

    Colourless compound --- Z/z ---> Grey ---G/g ---> Yellow.
    If there is no dominant Z then G/g cannot be expressed. ZzGg will produce yellow. zzGG will be colourless. ZZgg will be grey, 9:3:4 ratio

    Dominant epistasis is essentially the opposite. You need a recessive allele is the first epistatic gene for the second hypostatic gene to be expressed. Against Z/z and G/g for coat colour.

    Colourless compound --- Z/z ---> Grey ---G/g ---> Yellow.
    There needs to be a zz combination for the second gene to be expressed. zzGG will lead to yellow, zzgg will lead to Grey, ZzGG wil lead to colourless, ZZGG will be colourless. You need recessive homozygous in the first gene. 12:3:1 or 13:3 ratio
    Thank you for this post but I just wanted to clarify that your taking the first allele as the epistatic one? Because it could be the other way around.
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    predictions everyone? people must have some idea

    also with regards to photosynthesis and respiration is it always one or the other that comes up?
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    Yeah most likely they both will come up! Unit 4 tends to cover everything

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    (Original post by normalman)
    predictions everyone? people must have some idea

    also with regards to photosynthesis and respiration is it always one or the other that comes up?
    My teacher is a chief examiner and said last years paper was the end of a seven year cycle. So now they start again so anything could be on the paper. Also sometimes respiration and photosynthesis appear together in a question. But I'm pretty sure they always both come up.
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    (Original post by maisie__x)
    My teacher is a chief examiner and said last years paper was the end of a seven year cycle. So now they start again so anything could be on the paper. Also sometimes respiration and photosynthesis appear together in a question. But I'm pretty sure they always both come up.
    cheers! im relatively normal but my teacher said revise the kidney very well for f214??
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    Can someone explain Q 2)b)iii) to me please ?


    QP: http://www.ocr.org.uk/Images/62262-q...and-energy.pdf


    MS: http://www.ocr.org.uk/Images/62122-m...nergy-june.pdf

    Thanks in advance !
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    (Original post by normalman)
    cheers! im relatively normal but my teacher said revise the kidney very well for f214??
    Yeah we spent ages learning the kidney! I think it's because it's the biggest topic so it's likely that the paper will have the biggest proportion of questions about the kidney on it.
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    (Original post by maisie__x)
    Yeah we spent ages learning the kidney! I think it's because it's the biggest topic so it's likely that the paper will have the biggest proportion of questions about the kidney on it.
    thought so thanks maisie.

    what are everyones thoughts on my revision tactic, revise the even pages in f214 and the odd pages in f215. did this last year and managed an A overall somehow.
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    (Original post by normalman)
    thought so thanks maisie.

    what are everyones thoughts on my revision tactic, revise the even pages in f214 and the odd pages in f215. did this last year and managed an A overall somehow.
    What the
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    (Original post by normalman)
    thought so thanks maisie.

    what are everyones thoughts on my revision tactic, revise the even pages in f214 and the odd pages in f215. did this last year and managed an A overall somehow.
    Seriously ?


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    (Original post by a123a)
    Thank you for this post but I just wanted to clarify that your taking the first allele as the epistatic one? Because it could be the other way around.
    Yes I'm taking the first one as the epistatic one and the second as the hypostatic.
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    How are you guys tackling the suggest questions in the papers? i'm really struggling with answering these type of questions and applying my knowledge. I know the content, but sometimes i'm confused about what the question is actually asking. Really not looking forward to F215. There are so many random questions and topics in this unit.
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    (Original post by kobobo)
    How are you guys tackling the suggest questions in the papers? i'm really struggling with answering these type of questions and applying my knowledge. I know the content, but sometimes i'm confused about what the question is actually asking. Really not looking forward to F215. There are so many random questions and topics in this unit.
    .

    Plan is to write everything I think is correct probably just pick up marks at least none will get taken off


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    (Original post by cheeky 12)
    .

    Plan is to write everything I think is correct probably just pick up marks at least none will get taken off


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    Thanks i've been doing that so far. Its just so annoying how the examiners can be so picky. I read the examiners report for f211 last year and they were really picky about talking about vacuoles. You had to say large vacuole to get the mark. Its small points like that i'm scared i might lose out on.
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    (Original post by kobobo)
    Thanks i've been doing that so far. Its just so annoying how the examiners can be so picky. I read the examiners report for f211 last year and they were really picky about talking about vacuoles. You had to say large vacuole to get the mark. Its small points like that i'm scared i might lose out on.
    I know I hate how they done test our knowledge and test us on stupid things like including "large" or saying stuff like health AND disease like you'll lose a mark for not including and wth


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    Any predictions on what questions will come up for unit 4 this year?
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    (Original post by danwilliams33)
    Just thought I'd set up this thread so that we can start building a group of people for the exam in June.

    If you do A2 Biology then please join in on this. Share past papers or questions etc so that we can start to get our grades higher.

    A revision thread really helped for my AS so I think this will also be beneficial if we use this for revision aswell. ))))))

    Any predictions on what questions may come up this year?
 
 
 
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