7.Discuss the stages, events and significance of somatic and reproductive cell division.
II.Reproductive cell division– mechanism that produces gametes. Consists of a special two-step division called meiosiswhere the number of chromosomes in the nucleus is reduced by halfC.cell cycle in somatic cells– an orderly sequence of events in which a cell duplicates its contents and divides into 2I.homologous chromosomes– human cells contain 23 pairs of chromosomes, onemember from each pair is inherited from each parent and the 2 chromosomes that make up each pair are calledII.sex chromosomes, X and Y– XX for females and XY for males. Y is much smaller than X.III.diploid cell (2n)– because somatic cells contain 2 sets of chromosomes they are called diploid cellsa.Interphase– cell replicates DNA and produces additional organelles and cytosolic components in anticipation of cell division. Is a state of high metabolic activity: it is during the time that the cell does most of its growing. Contains 3 phases: G1, S, & G2. S stands for synthesis of DNA and G for gaps as there is no activity related to DNA replicationb.G1 phase– interval between mitotic phase and the S phase. Cell is metabolically active replicating organelles and cytosolic componentsc.G0 state – cells that remain in G! for a very long time, perhaps destined never to divide again d.S phase– ~8 hours long. DNA replication occurs causing the 2 identical cells formed to have the same genetic materiale.G2 phase– interval between S phase and mitotic phase. 4-6 hours long. Cell growth continues, enzymes and other proteins are synthesized in preparation for cell division and replication of centrosomes is completed. f.mitotic (M) phase– results in the formation of 2 identical cells, which consists of a nuclear division (mitosis) and cytoplasmic division (cytokinesis) to form 2 identical cells