Transcript Ch. 5.1- Cell Cycle

Ch. 5.1- Cell Cycle
Cell Cycle and Cancer Cells
Stages of the cell cycle
• 4 stages
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Gap 1 (G1)
Synthesis
Gap 2 (G2)
Mitosis
• A cell won’t proceed through the cycle until it’s
ready
▫ Prevents errors (cancer)
Gap 1 (G1)
• First stage of cell cycle
• Cell carries out its normal function
▫ Skeletal cells contracts to move joints
▫ Adrenal cells secrete hormones
▫ Intestinal cells absorb nutrients, etc.
• Cells increase in size & organelles increase in
number
• Cells must pass critical checkpoint before
proceeding to DNA synthesis
Synthesis (S)
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Second stage
Synthesis=“combining of parts to make a whole”
Cell makes a copy of its nuclear DNA
Contains 2 complete sets of DNA by end of the S
stage
Gap 2 (G2)
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Third stage
Continues to carry out normal functions
Additional growth occurs
Another critical checkpoint to ensure adequate
cell size and that DNA is undamaged.
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Mitosis (M)
• Fourth stage
• Includes 2 processes
▫ Mitosis= division of the nucleus and its contents
▫ Cytokinesis= division of the cytoplasm
• Results in 2 genetically identical daughter cells
Cells divide at different rates
• Aligned to your body’s need for those cells
• In human cells: S, G2, and M stages together take
about 12 hours
• Cell division is greater in children than adults
▫ Their cell cycles are also shorter
• Certain cells, such as neurons and lymphocytes,
divide rarely
▫ Usually in G0 stage
Exit Slip
• Ch. 5.1 assessment pg. 137
▫ # 1, 2, 3, 5, & 6
▫ MUST BE IN COMPLETE SENTENCES AND
YOUR OWN WORK!