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    we recently have done meiosis and there has been a lot of confusion about chromosomes and homologous pairs, even the teacher was doubting himself. its all about when its copied and what is a chromosome and chromatid and what isnt, . Like is a homologous pair of chromosomes when the chromatids duplicate and there are 4n of chromosomes and homologous chromosomes are when they split in meiosis 1 into two daughter cells?
    i get the whole process and what happens its just the chromosomes business at the start and what to call what is the bit everyone is getting confused by.
    much appreciated
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    (Original post by ewba)
    we recently have done meiosis and there has been a lot of confusion about chromosomes and homologous pairs, even the teacher was doubting himself. its all about when its copied and what is a chromosome and chromatid and what isnt, . Like is a homologous pair of chromosomes when the chromatids duplicate and there are 4n of chromosomes and homologous chromosomes are when they split in meiosis 1 into two daughter cells?
    i get the whole process and what happens its just the chromosomes business at the start and what to call what is the bit everyone is getting confused by.
    much appreciated
    Homologous chromosomes are chromosomes that controls the same characteristics (have the same exact genes at the same locus). Spindle fibres then attaches to the centromere of the chromosomes and separate the chromatids (these are two single strand of chromosomes joined by a centromere) during meosis II.

    Before meiosis occurs the DNA is doubled hence, at the start of meiosis I there is 4n chromosomes, and this number is then halved during meosis.
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    (Original post by kkboyk)
    Homologous chromosomes are chromosomes that controls the same characteristics (have the same exact genes at the same locus). Spindle fibres then attaches to the centromere of the chromosomes and separate the chromatids (these are two single strand of chromosomes joined by a centromere) during meosis II.

    Before meiosis occurs the DNA is doubled hence, at the start of meiosis I there is 4n chromosomes, and this number is then halved during meosis.
    At the start of meiosis there are not 4n chromosomes, there are still only 46 chromosomes (2n) in humans, however each chromosome has two sister chromatids joined at the centromere. It would be wrong to say that there are 92 chromosmomes, however there are 92 chromatids. In meiosis I, homologous chromosomes pair up to form a bivalent/tetrad and homologous chromosomes are separated in anaphase I to form two haploid cells (they each have 23 chromosomes and 46 chromatids). In anaphase II, the spindle attaches to kinetochores (proteins attached to the centromere) and they spindle splits the centromere and pulls sister chromatids to opposite poles of the cell to form four haploid daughter cells (they each have 23 chromosomes and 23 chromatids).
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    (Original post by Jpw1097)
    At the start of meiosis there are not 4n chromosomes, there are still only 46 chromosomes (2n) in humans, however each chromosome has two sister chromatids joined at the centromere. It would be wrong to say that there are 92 chromosmomes, however there are 92 chromatids. In meiosis I, homologous chromosomes pair up to form a bivalent/tetrad and homologous chromosomes are separated in anaphase I to form two haploid cells (they each have 23 chromosomes and 46 chromatids). In anaphase II, the spindle attaches to kinetochores (proteins attached to the centromere) and they spindle splits the centromere and pulls sister chromatids to opposite poles of the cell to form four haploid daughter cells (they each have 23 chromosomes and 23 chromatids).
    Thanks a lot, really helpful!
 
 
 
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