文档介绍：Cell proliferation and its regulation
Significance:
1. For the growth and development of a anism, and for the generation of offspring;
2. Produce anisms in unicellular species;
3. Renew the aging, apoptotic cells, and damaged tissue;
So, cell proliferation is one of the most important characters for life
Chapter 11
If damaged seriously by UV, mouse will die within several days.
1. The cell cycle
A. Overview of the cell cycle
The most basic function of the cell cycle is to duplicate accurately the vast amount of DNA in the chromosomes and then segregate the copies precisely into two ically identical daughter cells.
Cell cycle phases:
Interphase: G1-S-G2
M phase: Mitosis, Cytokinesis
Different cell cycle length
Some eukaryotic cell cycle times
The greatest variation occurs in the duration of G1
The shortest eukaryotic division cycles of all are the early embryonic cell cycles, no G1 and G2
Biochemical events of cell cycle
G1 phase: Synthesize proteins (RNA) for the DNA replication. Uncondense chromatin.
S phase: Synthesis of DNA and Histones
G2 phase: Synthesis of a few proteins (RNA)
M phase: Mitosis and meiosis and cytokinesis
Two daughter cells
Chromosome condense
Mitotic spindle
Contractile ring
Three categories of cells in vivo
Cycling cells
Dividing continuously—Stem cells
(2) G0 cells
Do not divide normally, but divide when given an appropriate stimulus: liver cells, lymphocytes
(3) Terminally Differentiated cells
Highly specialized, have lost the ability to divide until they die: muscle cells, red blood cells, nerve cells
Embryo cells
Cycling cells
G0 cells
Terminal cells