LIFE 102 Lecture Notes - Chromatin, Chromosome, Metaphase
Document Summary
All the dna in a cell constitutes the cell"s genome. Prokaryotic cells have a single dna molecule, while eukaryotic cells have a number of. Every eukaryotic species has a characteristic number of chromosomes in each cell nucleus. Somatic cells (nonreproductive cells) have two sets of chromosomes. Gametes (reproductive cells: sperm and eggs) have half as many chromosomes as somatic cells (one set of chromosomes) Eukaryotic chromosomes consist of chromatin, a complex of dna and protein that condenses during cell division. In preparation for cell division, dna is replicated and the chromosomes condense. Each duplicated chromosome has two sister chromatids, which separate during cell division. The centromere is the narrow waist of the duplicated chromosome, where the two chromatids are most closely attached. Gametes are produced by a variation of cell division called meiosis. Meiosis yields nonidentical daughter cells that have only one set of chromosomes, half as many as the parent cell.
