GENETICS. Mitosis and the Cell Cycle Cell reproduction.
Post on 14-Dec-2015
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Three reasons why cells reproduce by asexual reproduction:
1. Growth 2. Repair 3. Replacement
Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun.
Animated Mitosis Cyclehttp://www.cellsalive.com/mitosis.htm
As you can see Mitosis is a continuous cycle and does not stop at each phase like shown in the picture.
The Cell CycleThe sequence of growth and
division of a cell.95% of cell cycle
in interphase5% of cell cycle
in mitosis
Interphase
Growth Stage 1 (G1) – metabolic activity of the cell
Synthesis Stage (S) – metabolic activity of the cell, replication of DNA
Growth Stage 2 (G2) – metabolic activity of the cell, prepare for division
InterphaseInterphase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase
Nuclear membrane fades Chromosomes condense – can see
sister chromatids
and centromere Spindle fibers form Centrioles start to move
to opposite poles
Prophase
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Spindle fibers
No Centriolesmicrotubules
Metaphase
Chromosomes line up along the equator (middle) of the cell
Each chromatid is attached to spindle with centromere
Anaphase
Centromeres divideSister chromatids are pulled
apart to opposite poles of the cell
Each chromatid is now a separate chromosome
Telophase
Spindle fibers dissolveChromosomes reach the
opposite poles and begin to uncoil (lengthen)
Nuclear envelopes (2) reform
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