BIOB11H3 Chapter 14: chapter 14 notes
29 Apr 2011
School
Department
Course
Professor
Document Summary
Two major phases in cell cycle: m phase (mitosis + cytokinesis) and interphase (growth + preparation for dividing + other). Time between start of labeling period to appearance of the first labelled mitotic chromosomes = approximate length of g2. Dna replication + synthesis of additional histones occurs at the s phase. Most cells in the body are present in a state that precedes dna synthesis, called. They only proceed to s phase to complete a cell cycle if they receive an internal signal. Cell fusion experiments show that the cytoplasm of a replicating cell contains diffusible factors that stimulate initiation of dna synthesis in g1-phase nuclei, whereas g2-phase nuclei cannot respond to initiation factors present in s-phase cell cytoplasm. Prereplication complex can only occur during early g1 phase. G1 + m = premature chromosomal compaction to form a set of elongated compacted chromosomes. G2 + m = premature chromosome compaction but doubled.
