Shared Unit 3 Learning Objectives - University of Virginia BIOL 2100

Meiosis 10-4-21 • explain the purpose and location of meiosis - Meiosis occurs in sex organs. Germ cells undergo meiosis. - The purpose is to create gametes or genetically unique haploid cells made for fertilization. It exists to produce GENETIC VARIETY. - Location: in the sex organs. Germ cells go through meiosis to become gametes (sperm or egg). • explain the process of meiosis, noting what occurs in meiosis I versus II, the timing, purpose, and The outcome of crossing over - Meiosis 1 → Diploid → haploid The separation of homologous chromosomes to create two non-identical haploid cells. Reduce chromosome number from diploid to haploid. - Prophase 1 - Chromosomes form/condense. Nuclear envelope dissolves. - 2 MAJOR important events in prophase 1 - Synapsis - Pairing of homologous chromosomes - Crossing over - exchange of genes between homologous chromosomes, leading to new alleles and genetic diversity Metaphase 1 - Homologous chromosomes line up on a cell equator. Spindle apparatus is formed from centrosomes, and they attach to centromere. - Independent assortment - unique alignment of maternal and paternal versions of chromosomes, so different genes independently separate from one another during meiosis. - Anaphase 1 - The homologs (homologous chromosomes) are pulled apart and move to opposite ends of the cell. The sister chromatids stay attached to eachother. This pulling apart is random and adds to the genetic variability of the gametes. - Telophase 1 - Cytokinesis divides the cell. Result is 2 haploid daughter cells. - PRODUCTS: 2 genetically uniqu