Chapter 12: The Cell Cycle AP Biology Mrs. Ramon
The Life of a Cell
Chromosome Duplication
Cytokinesis in animal and plant cells
Prokaryotic Cell Division
Control of Cell Division Physical factors that stimulate or inhibit cell division Growth factors Density-dependent inhibition
Control of Cell Division Checkpoints G1 (restriction pt.) Ready to begin? Failure to pass this checkpoint causes the cell to enter G0 G2 Ready to divide? M Is cell division complete?
Cell Cycle Control
Cancer Cancer cells divide excessively and invade other tissues “Immortal” Example: HeLa Cells (1951) Mutations in specific genes cause cells to become cancerous Oncogenes Gas pedal for cell growth Mutation gas pedal is stuck down Tumor suppressors Brakes for cell division Mutation brakes don’t work