BIO 1330 unit 5.3

Cell Cycle Control

Ensures proper progression through stages; prevents uncontrolled division.

Checkpoints

G₁ (master), G₂, and M-phase checkpoints regulate cell cycle progression.

Cyclins & Cdks

Proteins that drive transitions between phases; cyclin binds Cdk to activate it.

Proto-Oncogenes

Normal genes that promote cell cycle when stimulated; mutations → oncogenes.

Tumor Suppressor Proteins

Halt cell cycle if DNA damage detected, e.g., p53.

p53

Master tumor suppressor: arrests cell cycle, activates DNA repair or triggers apoptosis.

Oncogenes

Mutated proto-oncogenes causing uncontrolled cell division; examples: HER2, Ras, ABL.

Tumor Suppressor Loss

Non-functional proteins allow damaged DNA to replicate; examples: p53, RB1, BRCA1/2, APC.

Mutagens

Agents that damage DNA (e.g., UV radiation causes thymine dimers).

Telomerase Activation

Enables indefinite cell division in cancer cells.

Benign Tumor

Localized, differentiated cells; slow-growing; few mutations.

Malignant Tumor

Poorly differentiated cells; metastasize; many mutations; cause cancer.

Angiogenesis

Cancer cells release signals to grow blood vessels nearby.

Growth Factor Loop

Cancer cells release growth factors to stimulate their own division.

Chromosomal Instability

Increased abnormalities with uncontrolled division.

Chemotherapy

Inhibits DNA replication or cell division.

Radiation

Causes severe DNA damage to kill cancer cells.

Targeted Therapy

Blocks specific oncogenic signals (e.g., Herceptin for HER2).

Immunotherapy

Uses immune system to attack cancer cells.

Surgery

Removes primary tumor.