BIOL 1090 Lecture Notes - Lecture 2: Synaptonemal Complex, Spermatogenesis, Mitosis
8 Sep 2017
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Document Summary
Ploidy: refers to the uniqueness of the genomic compliment of the whole genome (ex. Mitosis occurs in bodies stem cells and ends up with 2 diploid (n), genetically identical cells. Meiosis occurs in the germ (sex) cells and ends up with 4 haploid (n), genetically distinct cells. Homologous chromosomes are fully paired which is called synapsis (formation of synaptonemal complex) Crossing over occurs (breakage of chromatids and exchange of broken pieces between non-sister chromatids) Start to pull apart but remain joined at the cross over junctions called chiasmata. Spermatogonia (2n, 2c) goes through mitosis for several generations. Chromosome duplication of one cell goes into primary spermatocyte (2n, 4c) Goes through meiosis to produce secondary spermatocyte (n, 2c) Cytoplasmic brides connect to four spermatids which form sperm cells (n) Primary oocyte goes through meiosis 1 to divide into secondary oocyte.
