Mitosis

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Mitosis Cytokinesis

• Cell Growth and Reproduction Ch. 8.2

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Why do cells divide by Mitosis?

• Growth Repair
• Reproduction of single celled organisms under?
  conditions
• constant environment

Amobea Reproducing
3
Cells dividing by Mitosis.
Skin

• Identical to original cell
• Same chromosome
• Identical chromosome makeup

4
Cell Cycle
G or Growth 1 phase
S or DNA Synthesis
24 hours
M or Mitosis phase
/ / /
Growth 2
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Where is DNA located?

• 1. Nucleus
• 2. Chromosomes

DNA
I
6
Duplicated Chromosome(Late Interphase)
X
Sister Chromatids
Centromere
7
Spindle spindle fibers Pull apart the sister
chromatids
Spindle fibers
8
Cytokinesiscells cytoplasm divides splits
apart
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Stages of Mitotic Cell Division

• Prophase
• Metaphase
• Anaphase
• Telophase

• 1st
• middle
• apart
• far or separate

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Interphase

• Intermission
• Normal metabolic activities
• Major state
• DNA
• chromatin

11
Late Interphase

• Prepares for mitosis
• DNA doubles
• Sister chromatids
• Centrioles double in
• animals

X
X
X
X
X
X
12
Prophase

• Nuclear membrane disappears
• Doubled DNA condensed
• chromosomes
• Spindle fibers

13
Metaphase

• Chromosomes line up mid- cell
• Facing inward

14
Anaphase

• Chromosomes move to opposite poles at
• Centrioles in
• animals
• Spindle apparatus in
• plants

15
Telophase

• Cells divide
• Cell plate or membranes form
• Nucleus reappears

16
Returns to Interphase

• Intermission
• Normal metabolic activities
• Major state
• DNAchromatin

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Plant versus Animal Mitosis

• Plant
• Cell wall from
• cell plate in telophase
• Sindles

• Animal
• No cell wall
• membrane cytokinesis
• Centrioles

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Animal Telophase
Interphase
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Plant Anaphase
Interphase
20
Cancerous cells...

• 1.Divide too many times
• 2.Divide into more than two cells!
• Masses of cells
• tumors
• benign
• malignant