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Cell Reproduction. Why do Cells Divide?. Section 5-1, 5-2. Why must the cell divide?. Nutrients and waste pass through the cell membrane When the cell membrane no longer has a large enough surface area to transport the volume of the cell It divides!. How long do our cells last?. - PowerPoint PPT Presentation
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Cell Reproduction
Why do Cells Divide?
Section 5-1, 5-2
Why must the cell divide?
Nutrients and waste pass through the cell membrane
When the cell membrane no longer has a large enough surface area to transport the volume of the cell
It divides!
How long do our cells How long do our cells last?last?
In the human body our cells In the human body our cells last between two weeks (a skin last between two weeks (a skin cell) to cell) to 16 years (our muscles)16 years (our muscles)
Cell division occurs more Cell division occurs more rapidly in embryos and rapidly in embryos and childrenchildren
The Cell Cycle
InterphaseThe longest phase of the cell cycle
• G1 phase – the growth phase, organelles increase
in number, longest phase of interphase
• S phase – chromosomes are replicated
• G2 phase- cell continues to grow
What is a Chromosome?
MitosisThe Division of Chromosomes
Specifically the chromosomes
in somatic cells
ProphaseProphaseChromosomes shorten
and thicken
Nuclear membrane disappears
Spindle fibers form
Centrioles move to opposite poles
MetaphaseMetaphase
Chromosomes line up at equatorial plate
Attach to spindle fibers with centromere
AnaphaseAnaphase
• Chromosomes move towards poles
TelophaseTelophase
• Nuclear membrane forms around chromosomes
Cytokinesis
The division of the cytoplasm
The cell membrane forms between the two new identical daughter cells