BIOLOGY 1A03 Lecture Notes - Spindle Apparatus, Sister Chromatids, Photographic Emulsion

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Joe Kim

Document Summary

Cells spend most of their time in interphase. Researchers used radioactive isotopes to trace chromosomes (phosphorous and thymidine) Figured out there was an s phase (synthesis phase) 1. feed radioactive thymidine to cells growing in culture. Only cells in synthesizing will have label: wash extra thymidine out. S phase is about 8 hours long and there is a lagging gap between s phase and m phase. Eukaryotic chromosomes normally exist as extremely long, threadlike strands consisting of dna associated with globular proteins called histones. Dna copies in a replicated chromosome is called chromatid. Cell cycle-interphase g1 phase: cell growth and duplication of organelles. S phase: dna synthesis (chromosomes replicate) g2 phase: cell growth and duplication of organelles continues to build the protein machinery Before mitosis occurs, the parent cell must be large enough size and must have required organelles, so that daughter cells will operate normally. Nerve cells that are mature, and muscle cells.