1Biology 20 CELL DIVISION – MITOSIS Mitosis: Binary fission (p. 129, Fig. 8.3A): Cell cycle: • Divided into two phases: • Interphase: • Mitotic phases: • Karyokinesis: 4 Phases involved: 1) 2) 3) 4) • Cytokinesis: “The Process” of Cell Division: Interphase: 3 phases of Interphase: 1. G1 (Gap) phase: 2. S phase: 3. G2 (Gap) phase:2 Mitotic Phases: • Karyokinesis: • Cytokinesis: 1) Prophase: • Longest of the Mitotic phases. Why? • Chromatin: • Chromosomes: • Sister chromatids (duplicated chromosome): • Centromere: • Nuclear envelope & nucleolus: Early Prophase Late Prophase 2) Metaphase: What occurs? Metaphase plate: 3) Anaphase: What separates? Where does the separation occur?3 4) Telophase: What occurs? Cleavage Furrow: Cell Plate: Cytokinesis: Results in: Control of Cell Division Why do living organisms have cell division? 1) 2) 3) Types of cells that can undergo cell division: Are there cells that can not undergo cell division?4Factors that Influence Cell Division: 1. Growth factors: 2. Cell density: Density dependent inhibition (Fig. 8.8A): 3. Restriction points (Fig. 8.9A): 4. Cell size: 5. Regulatory proteins (cyclical changes): Cell division and Cancer cells: Cancer cells: Tumor: Benign tumor:5Malignant tumor (Fig. 8.10): Metastasis: Tumor suppressor genes (Fig. 11.15B): p53 gene: p21 gene: normal BRAC1& BRAC2: The role of telomeres & telomerases in cell division: Telomere (p. 243, Fig. 12.13A): Function: Limits: Telomerases: Absent in: Function: Which types of human cells “normally” posses telomerase? Types of cancers & possible cause(s): Carcinogen: Carcinomas: Sarcomas: Leukemia &
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