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Download Cell Division: Mitosis & Meiosis
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Regulation of the Cell Cycle Chapter 10, Section 3 (p.250-253) External Regulators • Growth Factors – Molecules that bind to surface receptor proteins • Stimulate cell division External Regulators • Cell-Cell Recognition – Surface proteins in direct contact • Inhibits cell division Internal Regulators • CDKs • Cyclins – Enzymes that “activate” other proteins by attaching a phosphate group – Always present in cell – Proteins that bind to CDKs – Fluctuates throughout cell cycle • Concentration • Type Stimulate cell cycle when together! Internal Regulators P53 & BRCA1 • Stalls cell from progressing to next phase – DNA can be repaired • If damage cannot be fixed – Apoptosis MAD • Prevents cell from progressing to anaphase when chromosomes are not properly attached to spindle fibers Inhibit cell cycle! Cancer • Caused by – The body’s loss of control over the cell cycle • Stimulation of cycle • Cells forgetting to die – Accumulation of cells = tumor Characteristics of Cancer • Hyperplasia: uncontrolled cell division • Dedifferentiation: loss of specialized functions of normal cells • Invasiveness: ability to grow and spread into neighboring tissue • Angiogenesis: promote the formation of blood vessels for nourishment • Metastasis: cells can detach and travel via blood to other areas of the body, starting new tumors
