HSCI 100 Lecture Notes - Lecture 5: Sister Chromatids, Spindle Apparatus, Nuclear Membrane

• School: Simon Fraser University
• Department: Health Sciences
• Course: HSCI 100
• Professor: Nienke Van Houten

Document Summary

Each chromosome is a single linear dna molecule (double helix) with a string of nucleotides that spell out genes. Total dna in all the chromosomes of an organism is its genome & a complete genome is nearly always found in every cell. Somatic cells (body cells)- have 46 chromosomes called diploid (2n) Germ cells (sex cells)- 23 chromosomes not in pairs, called haploid (n) Meiosis: what the somatic and germ cells do. Mitosis: only what germ cells do: homeostasis & repair. G1 stage growth: cell grows in size & accumulates materials, proteins need for dna replication are synthesized. S stage dna synthesis: dna replication occurs, copy of each chromosomes (sister chromatids) G2 stage growth: proteins needed for division are synthesized (microtubules) 1 duplicated chromosome: 2 chromatids; chromatin; not condensed. Chromosomes condensation: dna wraps around histines; twists & loops around itself. One duplicated chromosome condenses: consists of 2 chromatids held together by centromere.