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Mitosis & Cytokinesis
Cell Growth and Reproduction Ch. 8.2
Why do cells divide by Mitosis?
• Growth &Repair• Reproduction of
single celled organisms under? conditions
• constant environment
AmobeaReproducing
Cells dividing by Mitosis…….
• Identical to original cell
• Same chromosome #
• Identical chromosome makeup
Skin
Cell Cycle
24 hours
“G” or Growth 1 phase
“S” or DNASynthesis
Growth 2
“M” orMitosisphase
///
Where is DNA located?1. Nucleus
2. ChromosomesDNA
Duplicated Chromosome(Late Interphase):
SisterChromatids
Centromere
Spindle & spindle fibers: Pull apart the sister chromatids
Spindle fibers
Cytokinesis:cell’s cytoplasm divides & splits apart
Stages of Mitotic Cell Division
• Prophase
• Metaphase
• Anaphase
• Telophase
• “1st”• “middle”• “apart”• “far” or
separate
Interphase
• “Intermission”
• Normal metabolic activities
• Major state
• DNA=
chromatin
Late Interphase• Prepares for
mitosis• DNA doubles=• Sister chromatids• Centrioles double
in• animals
Prophase • Nuclear membrane disappears
• Doubled DNA = condensed
• “chromosomes”• Spindle fibers
Metaphase
• Chromosomes line up mid- cell
• Facing inward
Anaphase• Chromosomes move
to opposite poles at• Centrioles in• animals• Spindle apparatus
in• plants
Telophase
• Cells divide• Cell plate or
membranes form
• Nucleus reappears
Returns to Interphase• “Intermission”• Normal metabolic
activities• Major state • DNA=chromatin
Plant versus Animal Mitosis
Plant:
• Cell wall from
• cell plate in telophase
• Sindles
Animal:
• No cell wall
• membrane cytokinesis
• Centrioles
Animal Telophase
Interphase
Plant AnaphaseInterphase
Cancerous cells……...
1.Divide too many times
2.Divide into more than two cells!
• Masses of cells =
• “tumors”
• benign
• malignant
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