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    (Original post by nasira372)
    What board are you doing mate, MEI?
    Edexcel.
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    (Original post by oHellno)
    Edexcel.
    (Original post by liviaaa)
    I'm doing edexcel - with those topics too ^.
    Cool, me too
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    What about for biology/chemistry?

    Im guessing everyone does AQA like me or am I wrong?
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    (Original post by nasira372)
    What about for biology/chemistry?

    Im guessing everyone does AQA like me or am I wrong?
    I do AQA bio and OCR chem.

    I'm having a problem understanding meiosis, so I posted a question in the bio forum along the lines of:

    "If the starting cell has 46 chromosomes, the 2 daughter cells have 23, why do the daughter cells after meiosis 2 have 23 also?".

    You are all free to answer
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    (Original post by thegodofgod)
    Cool, me too


    I've just revised the sin/cos/tan graph transformations for C2 - it's my least favourite section - it's not even proper maths, haha.
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    (Original post by SteveCrain)
    I do AQA bio and OCR chem.

    I'm having a problem understanding meiosis, so I posted a question in the bio forum along the lines of:

    "If the starting cell has 46 chromosomes, the 2 daughter cells have 23, why do the daughter cells after meiosis 2 have 23 also?".

    You are all free to answer
    Stage 2 of meiosis is the same as mitosis, so the chromosomes double and split in 2, so 23 in each.
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    (Original post by nasira372)
    What about for biology/chemistry?

    Im guessing everyone does AQA like me or am I wrong?
    I do AQA for both - not everyone does though.
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    (Original post by liviaaa)
    Stage 2 of meiosis is the same as mitosis, so the chromosomes double and split in 2, so 23 in each.
    why does it show a full chromosome in the cell after the first split, and a single chromatid in the final daughter cells?

    and in mitosis, how is the number equal after the chromatids are separated?
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    (Original post by liviaaa)


    I've just revised the sin/cos/tan graph transformations for C2 - it's my least favourite section - it's not even proper maths, haha.
    Ah, feels good to have already finished AS maths :cool:
    D1 in just over a months time though, which is not too difficult. Much easier than M1 though.
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    (Original post by SteveCrain)
    why does it show a full chromosome in the cell after the first split, and a single chromosome in the final daughter cells?
    Meiosis 1 consists of the chromosomes replicating, lining up on the spindle and each homologous chromosomes going to seperate poles, to form 2 cells. These 2 cells each have 2 choromosomes.

    Meiosis 2, is the same as mitosis. It involves the chromosomes lining up on the spindle and the chromatids separate, leading to 4 haploid cells.
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    (Original post by Normandy114)
    Ah, feels good to have already finished AS maths :cool:
    D1 in just over a months time though, which is not too difficult. Much easier than M1 though.
    Haha How have you finished it all already?
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    (Original post by liviaaa)
    Haha How have you finished it all already?
    Did all of my AS exams in January except one, because our sixth form is Years 11-13.
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    (Original post by Normandy114)
    Did all of my AS exams in January except one, because our sixth form is Years 11-13.
    Oh okay! I thought some uni's only allow a levels to be completed over 2 years?
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    (Original post by liviaaa)
    Oh okay! I thought some uni's only allow a levels to be completed over 2 years?
    That's right, but I did all my exams in January so it's technically over 2 years. The school made that mistake with the year above us, who got barred from several university courses because they did modular exams at the end of year 11.
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    i am taking Chem,bio,physics n statistic....i want to do mbbs
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    (Original post by Normandy114)
    That's right, but I did all my exams in January so it's technically over 2 years. The school made that mistake with the year above us, who got barred from several university courses because they did modular exams at the end of year 11.
    Oh okay So you did your GCSE's in Years 9 and 10?
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    (Original post by liviaaa)
    Oh okay So you did your GCSE's in Years 9 and 10?
    :yes:
    Didn't revise for them though so came out with some relatively bad grades, doesn't matter too much though as I can still get into most places.
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    (Original post by Normandy114)
    :yes:
    Didn't revise for them though so came out with some relatively bad grades, doesn't matter too much though as I can still get into most places.
    I'm sure they're not that bad then.

    It's a bit of a disadvantage taking GCSE's early... but then again you get 3 years learning time for A levels - swings and roundabouts.
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    (Original post by SteveCrain)
    I do AQA bio and OCR chem.

    I'm having a problem understanding meiosis, so I posted a question in the bio forum along the lines of:

    If the starting cell has 46 chromosomes, the 2 daughter cells have 23, why do the daughter cells after meiosis 2 have 23 also?

    You are all free to answer
    This confused me for the longest time.

    A somatic cell has 46 chromosomes (which is basically one chromatid). But just before meiosis the DNA replicates so you have two sister chromatids, during meisos 1 the homologous chromosomes are separated, so you have half the number. So the daughter cells have 23 chromosomes, but you have to remember that each chromosome has TWO chromatids.
    During meiosis 2, much like mitosis, the sister chromatids are pulled apart. So the final daughter cells contain 23 chromatids (but for an annoying reason, you are still expected to call them chromosomes - maybe because usually chromosomes are just the one chromatid?)

    There isn't actually any DNA replication between the two divisions.

    (Maybe you've already got this sorted, but it helped me to write it out )
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    (Original post by oHellno)
    This confused me for the longest time.

    A somatic cell has 46 chromosomes (which is basically one chromatid). But just before meiosis the DNA replicates so you have two sister chromatids, during meisos 1 the homologous chromosomes are separated, so you have half the number. So the daughter cells have 23 chromosomes, but you have to remember that each chromosome has TWO chromatids.
    During meiosis 2, much like mitosis, the sister chromatids are pulled apart. So the final daughter cells contain 23 chromatids (but for an annoying reason, you are still expected to call them chromosomes - maybe because usually chromosomes are just the one chromatid?)

    There isn't actually any DNA replication between the two divisions.

    (Maybe you've already got this sorted, but it helped me to write it out )
    I'm fairly sure it is wrong to call them chromosomes though, because chromosomes are almost always labelled as having 2 chromatids :|.
    If the chromatids are pulled apart into 4 new cells during mitosis 2 they don't magically become chromosomes unless they are about to divide again surely (>.<)

    This was poorly taught at GCSE too tbh ¬_¬
 
 
 
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