Unit 4 · 4.6 — Regulation of Cell Cycle [cite: 9, 13, 28]

Everything to learn here

• Concept: Strict internal controls and checkpoints strictly regulate progression through the cell cycle (specifically the G1, G2, and M checkpoints) [cite: 13, 14].
• Concept: Cancer results directly from a catastrophic loss of cell cycle control, frequently due to mutated proto-oncogenes becoming hyperactive or tumor suppressor genes becoming deactivated [cite: 13, 14].
• Vocabulary: Cyclins — regulatory proteins whose internal concentrations fluctuate cyclically to command the cell cycle's timing [cite: 14].
• Vocabulary: Cyclin-Dependent Kinases (CDKs) — enzymes that must bind physically to cyclins to become active; they trigger progression through strict checkpoints [cite: 14].
• Vocabulary: Apoptosis — highly organized, programmed cell death occurring automatically when irreparable DNA damage is detected at a checkpoint [cite: 14].
• Concept: Internal checkpoints regulate the cell cycle by ensuring each stage is completed correctly before the next begins.

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