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Mitosis. How do living things grow and repair themselves?. Why do cells divide?. Reproduction Growth Repair. The cell cycle. Regular sequence of growth and division of cell 3 parts: Interphase Mitosis Division of cytoplasm. 1. Interphase. Longest part of cell cycle
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Mitosis How do living things grow and repair themselves?
Why do cells divide? • Reproduction • Growth • Repair
The cell cycle • Regular sequence of growth and division of cell • 3 parts: • Interphase • Mitosis • Division of cytoplasm
1. Interphase • Longest part of cell cycle • Cell grows to mature size • To prepare to divide, each chromosome makes a copy of itself
Length of interphase • Different kinds of cells spend different lengths of time in interphase Human skin cells Human bone cells
2. Mitosis • Part where cell’s nucleus divides into two identical new nuclei • 4 stages of mitosis (PMAT): • Prophase • Metaphase • Anaphase • Telophase
Prophase • Spindle forms • Centrioles move to opposite poles • Chromosomes become visible
Metaphase • Chromosomes line up along the equator
Anaphase • Chromosomes and duplicates separate and move to opposite poles
Telophase • Nuclear membrane forms around each group of chromosomes • Chromosomes unwind • Cytoplasm starts to divide
End result of mitosis • Two identical daughter cells • Both cells have the same number of identical chromosomes
3. Division of cytoplasm • Cytoplasm divides and one cell becomes two new cells with identical nuclei Animal cells Plant cells