BIO1011 Lecture Notes - Lecture 8: Cell Division, Sister Chromatids, Centromere
6 Aug 2018
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Document Summary
Both are part of a common cell cycle. In adult organism most cells have exited cycle and are terminally differentiated. Sometimes chromosomes do not segregate correctly, end up with cells with extra chromosomes or chromosomes missing called non disjunction. Dramatic consequences: responsible for up to 50% of miscarriages -if viable, causes disorders e. g. downs syndrome extra chromosome 21. Organelles in cells that contain the genetic material. Diploid organisms have two copies of each chromosome. Dna + proteins = chromatin: 2n diploid n -haploid, homologous chromosomes carry the same genes - not identical, sister chromatids are the two copies of a newly replicated chromosome - identical. Chromosomes vary in number in different organisms. 22 pairs of autosomes-same in both sexes: chromosomes vary in size and centromere position. Metacentric in middle: acrocentric towards end, telocentric at end. Cell divides to give two identical daughter cells. Dna has to be replicated then passed down with absolute fidelity.
