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Unformatted text preview: First, (as you've said) each human cell has 46 chromosomes . After synthesis (S phase), each of these chromosomes will be composed of 2 sister chromatids. Therefore, there are 96 chromatids in a somatic cell after S phase. Now, although you may say there are 96 sister chromatids, you still have 46 chromosomes (or 46 duplicated chromosomes...46*2=96). If you say that a human cell has 96 chromosomes, you are also implying that it is no longer a diploid but now somehow a tetraploid. But in a normal cell, it can only be a diploid (somatic cell) or haploid (in gametes) state. Okay, so the book is right in saying that each cell has 1 chromatin after mitosis because during anaphase, all 46 duplicated chromosomes (sister chromatids) get separated into nonduplicated chromosomes or chromatids. So you still have a whole chromosome (or also called a chromatid). IN MEIOSIS: Anaphase I, 23 homologous pairs separate (so essentially 23 duplicated chromosome to one pole and 23 duplicated chromosomes to the other pole)....
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- Spring '08