Download Cell Cycle

Cell Division
• process by which cells reproduce themselves
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Cell Division in Prokaryotes
• Binary fission
• process where DNA is copied and cells are
divided into two identical haploid cells
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Cell Division in Eukaryotes
• Cell Cycle
– the repeating set of events in the life of a cell
– Regular pattern of growth, DNA duplication, and
cell division
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Cell Division in Eukaryotes
• Cell Cycle
– 2 parts with 4 stages
1. Interphase (includes Stages 1, 2, 3)
2. M phase (includes Stage 4)
– 4 Main Stages
1. Gap 1 (G1)
2. Synthesis (S)
3. Gap 2 (G2)
4. Mitosis and Cytokinesis (M)
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Cell Division in Eukaryotes
1. Interphase
– consists of 3 Stages
1. (G1) = growth (increase in size) and increase
number of organelles
• Critical checkpoint before moving to Stage 2
2. (S) = DNA replication (copy DNA)
3. (G2) = more growth and preparation
• Critical checkpoint before moving to Stage 4
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Cell Division in Eukaryotes
2. M phase
– consists of 1 Stage
4. (M) = 2 processes
• Mitosis = division of the nucleus & DNA
• Nuclear envelope disappears
• DNA condenses and separates
• 2 new nuclei form
• Cytokinesis = division of cytoplasm
Result is 2 identical cells
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Control of the Cell Cycle
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Rate of the Cell Cycle
– In humans
– S, G2, M = 12 hours
– G1 = differs based on cell type
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Cell Size
– If too small
– Can’t hold all necessary organelles
– If too large
– Necessary materials cannot move across the
cell membrane fast enough
– Surface area to Volume ratio
– too much volume, not enough surface area
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