BIOA01H3 Lecture Notes - Lecture 8: Nondisjunction, Telophase, Sister Chromatids

• School: UTSC
• Department: Biological Sciences
• Course: BIOA01H3
• Professor: Steve Joordens

Document Summary

Sexual reproduction involves combining genomes from two sources to produce a new individual that is different in genetic make-up from the two sources. Haploidy condition of having one complete set of chromosomes. Diploidy condition of having two sets of chromosomes. Meiosis special nuclear division in which chromosome number is reduced from 2n (diploid) to n (haploid) For sexual reproduction dna replication is followed by 2 divisions. Chromosomes begin condensing and get shorter, transcription stops. Mtoc duplicates and migrates to opposite poles. Nuclear envelope breaks down: sister chromatids are held tightly along length, not just at centromere, sister chromatids share one functional kinetochore (different from mitosis, only held in centromere regions and each sister chromatid had its own kinetochore. After homologous chromosomes synapse, non-sister chromosomes swap homologous portions: precise lining up of the dna and breaking the dna helix and changing partners, causes recombination of dna. Genetic variation: important consequence of synapsis and reciprocal change.