BIO152H5 Lecture Notes - Lecture 7: Sister Chromatids, Parthenogenesis, Metaphase
Document Summary
Mitosis: mechanism for constancy: the parent nucleus produces two daughter nuclei, identical to the parent to each other. A closer look at chromosomes: sister chromatids, homologous pairs, centromeres etc. There are 23 different types of chromosomes. Meiosis two haploids gametes-one from each parent unite in fertilization to form to form a genetically unique diploid zygote. In prophase the pair of homologous chromosomes is different form mitosis in meiosis: homologs are going to pair, in meiosis 1 , homologs are going to separate and in meiosis. 2, the sister chromosomes are going to separate: a full complement of chromosomes is restored during fertilization. Prior to meiosis: chromosomes replicate forming sister chromatids: 1. Meiosis ii: each sister cell is haploid: at anaphase 4 haploid cells result (genetically different from one another and genetically different form the parent cell) Meiosis is a mechanism for diversity the parent nucleus produces 4 haploids genetically different. Meiotic errors nondisjunction: failure of homologous to separate *trisomy.
