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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?.
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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? • In the human body our cells last between two weeks (a skin cell) to 16 years (our muscles) • Cell division occurs more rapidly in embryos and children
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
MitosisThe Division of Chromosomes Specifically the chromosomes in somatic cells
Prophase • Chromosomes shorten and thicken • Nuclear membrane disappears • Spindle fibers form • Centrioles move to opposite poles
Metaphase • Chromosomes line up at equatorial plate • Attach to spindle fibers with centromere
Anaphase • Chromosomes move towards poles
Telophase • Nuclear membrane forms around chromosomes
Cytokinesis The division of the cytoplasm The cell membrane forms between the two new identical daughter cells