The Cell Cycle

The Life Cycle of a Cell Cell Cycle = events from one cell division to the next

The Cell Cycle

Divided into two parts Interphase M phase

Interphase Three parts –G1 – cell growth –S – DNA synthesis –G2 – preparation for division

M Phase Two Parts –Mitosis – nuclear division –Cytokinesis – division of cytoplasm

Control of the Cell Cycle G1 Checkpoint – decision to divide –Some cells exit the cell cycle and go into G0 –Example: Nerve and muscle cells

G2 Checkpoint –Allows cell to begin mitosis

Mitosis Checkpoint – Allows cells to begin G1 again

CANCER Results from uncontrolled cell division The genes that code for the proteins that regulate the checkpoints are mutated

MITOSIS 4 Phases –Prophase –Metaphase –Anaphase –Telephase orials/cell_cycle/cells3.htmlhttp:// orials/cell_cycle/cells3.html

Prophase –Chromatids appear –Nuclear membrane disappears –In animals, spindle appears –Centrioles move to opposite poles

Prophase

Metaphase Chromatids line up at equator

Metaphase

Anaphase –Centromeres divide –Chromatids more toward opposite poles

Anaphase

Telophase –Nuclear envelopes form –Chromosomes uncoil –Spindle dissolves –Cytokinesis begins

Telophase

Cytokinesis Division of the cytoplasm Forms cleavage furrow in animal cells Cells Alive Animation Cytokinesis Video

Online Tutorial About the Cell Cycle orials/cell_cycle/cells2.html