Bio lecture 17 - Cell Cycle

G1 Phase

cell growth and preparation for DNA replication

S Phase

Synthesis of DNA (replication)

G2 Phase

Growth and preparation for chromosomal segregation

M Phase

Mitosis (nuclear division) and cytokinesis (cell division)

G0 Phase

 “Quiescent” cells exit at G1 into G0)

Checkpoint

a point at which the cell cycle stops (“arrested”) unless it gets a “go-ahead” signal

Cyclin

proteins that activate cyclin-dependent kinases (CDK’s)

CDK (cyclin dependent kinase)

protein kinases that require cyclin to be activated. CDKs regulate the cell cycle by moving the cell passed checkpoints

Protein Kinase

enzymes that catalyze the addition of a phosphate group to a target protein - known as phosphorylation

Protein phosphorylation

the addition of a phosphate group to a target protein - done by protein kinases

MPF (M-phase promoting factor)

a cyclin-dependent kinase that triggers transition from G2 -> mitosis

Growth factor

small proteins that stimulate cell growth

PDGF - Platelet-derived growth factor

growth factors released from platlets that assist in wound-healing

p53

tumor suppressor protein. stops damaged cells from porgressing through the cell cycle.