BIOL1001 Lecture Notes - Lecture 23: Semiconservative Replication, Sexual Reproduction, Actomyosin Ring
Document Summary
The cell cycle: cells arise from other cells. Key words: chromatin = in eukaryotes, dna is coiled around histones proteins (nucleosomes) to form chromatin. Nb: can be loosely or tightly packed and amount of packing varies through the cell cycle: chromosomes = a continuous stretch of dna (and associated proteins) [g0 phase] (2) s phase (synthesis phase) (3) g2 phase: m phase (4) mitosis (5) cytokinesis. Centrosome = a single structure, often near the nucleus, which produces microtubules. Centrioles = a pair of structures within the centrosome of cell (made of mts) Nb: many plants and fungi lack centrioles. Immediately follows the completion of mitosis- often the lonest part of the cell cycle (1) g1 phase: phase prior to duplication (2) s phase, period in which dna replicates. Each homologous chromosome is duplicated to form 2 sister chromatids, joined by a centromere (ie: two identical copies) Nb: chromatids not considered to be separate chromosomes until they separated during mitosis.
