MITOSIS, CYTOKINESIS, MEIOSIS AND APOPTOSIS Michelle Gehringer Department of Biochemistry and Microbiology, University of Port Elizabeth, South Africa Keywords: Cell cycle, checkpoints, growth factors, mitosis, meiosis, cyclin, cyclin dependent protein kinases, G1 phase, S phase, spindle, prophase, anaphase, metaphase,
Summary: At the end of meiosis, 4 daughter cells are formed = eggs or sperm. Each contains half as many chromosomes as the parent cell (n); each cell is genetically different from its parents and from its siblings. Fertilization of an egg by a sperm restores the chromosome number to 2n.
Human sex cells are produced by a two part cell division process called meiosis. Through a sequence of steps, the replicated genetic material in a parent cell is distributed among four daughter cells. Meiosis produces gametes with one half the number of chromosomes as the parent cell. Because these cells have one half the number of chromosomes as the parent cell, they are haploid cells. Human sex cells contain one complete set of 23 chromosomes. There are two stages of meiosis: meiosis I and meiosis II.