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Meiosis/Mitosis genetics maths problems

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    Hi can anyone help me with these biology mathsy problems?
    They are stretch and challenge problems so I'm not tested on them, its just a learning experience. I've given them a go, but I'm really struggling

    Can anyone else solve them?

    For part one, i got like 204000:1 but i think this is wrong
    for part 2 I got 900
    and for part 3 I really wasn;t sure. Is it 300^3 or something?

    p.s that weird symbol is supposed to be a micrometre as 1000nm = 1 micrometre
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    The first 2 seem pretty correct to me, as for the last one, I can't tell if it's a trick question or not, but I believe that it is 3x10^9 / 900, this is because a diploid cell has 6x10^9 base pairs, but the number of genes is going to be half of that divided by 900, because you have 23 PAIRS of chromosomes per diploid cell, so the genes on each pair will actually be the same (although the alleles will be different, and the Y chromosome in males is missing a lot of genes compared to the X chromosome, but we won't worry about that). So I think the answer should be 3.3x10^6. As the question says though, this is way way more genes than there actually are, because most of the genome is non-coding for proteins
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