Mitosis160-page2 - Chromosomes are visible only when...

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Cell Reproduction: Mitosis - 2 Before discussing how cells divide, it's probably useful to discuss the structure of chromosomes and chromosome terms (of which there are a sufficiency). Structure of Chromosomes Chromosomes are composed of DNA and protein, a mixture called chromatin. During the normal metabolic activities of the cell the collective DNA, or chromatin, appears dense and grainy. DNA is a thread-like double chain of nucleotides. The DNA coils around the histone proteins to form nucleosomes. Chromosomes continue to tightly coil and fold back on themselves prior to cell division.
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Unformatted text preview: Chromosomes are visible only when tightly coiled. Human Male Karyotype Each species has a characteristic number of chromosomes. Humans have 46 chromosomes; potatoes and chimpanzees have 48 chromosomes. The pea plant, important in Mendelian genetics has 14, the even more famous fruit fly has 8. Some ferns have chromosome numbers exceeding 1000. Chromosomes are self-duplicating and must do so prior to each cell division. There is an essential vocabulary associated with chromosome appearance before and after duplication....
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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