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Mitosis- Chapter 6

Mitosis- Chapter 6. Sections 1-3. Objectives- . Identify four examples of cell division in eukaryotes and one example in prokaryotes. Differentiate between a gene, a DNA molecule, a chromosome, and a chromatid. Compare haploid and diploid cells.

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Mitosis- Chapter 6

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  1. Mitosis- Chapter 6 Sections 1-3

  2. Objectives- • Identify four examples of cell division in eukaryotes and one example in prokaryotes. • Differentiate between a gene, a DNA molecule, a chromosome, and a chromatid. • Compare haploid and diploid cells. • Differentiate between homologous chromosomes, autosomes, and sex chromosomes. • Predict how changes in chromosome number or structure can affect development.

  3. Why do cells divide? • Repair • Growth & development • Make gametes (sex-cells; sperm or egg)

  4. Asexual Reproduction • Reproduction by • Binary Fission • Fragmentation • Vegetative Propagation • Genetically identical offspring • Don’t need partner to reproduce

  5. Binary Fission

  6. Fragmentation

  7. Sexual Reproduction • Reproduction requires gametes • Genetically different offspring

  8. Sexual Reproduction- Simple version • Daddy’s sperm meet Mommy’s egg • This sperm “eats” a hole for itself into the egg to get its DNA in • This fertilized cell is called a zygote • This zygote divides and grows into a baby by Mitosis

  9. Prokaryotes vs Eukaryotes • Prokaryotes use asexual reproduction • Eukaryotes may use asexual OR sexual reproduction • Prokaryotes reproduce more quickly • Eukaryotes reproduce more slowly

  10. Prokaryotes vs Eukaryotes

  11. Focus on Eukaryotes (us) • Gene- part of DNA that codes for particular trait • Chromosome- made of coiled DNA and protein

  12. More Important Terms • Centromere- center point where two chromatids are attached • Chromatid- half of a chromosome Chromosome

  13. Eukaryote Cell Division http://www.cellsalive.com/cell_cycle.htm

  14. Cell Cycle S phase (DNA synthesis; chromosome duplication) • Consists of • Interphase • Mitosis Interphase (90% of time) G1 G2 Mitotic phase (M) (10% of time) Mitosis Cytokinesis

  15. Interphase • Cell spends 90% of its time here • G1- 1st growth phase • S- synthesis of DNA • G2- 2nd growth phase • There are checkpoints throughout the cell cycle

  16. Mitosis- (growth/repair) • Begins with 1 diploid cell, ends with 2 diploid cells • Diploid = twice the number of chromosomes (2N) • One chromosome set comes from mom, the other from dad • All of our body cells are diploid (except for sperm and egg) Remember: produces 2 genetically identical cells!

  17. Basic Steps of Mitosis: “PMAT” • P- Prophase • M- Metaphase • A- Anaphase • T- Telophase

  18. Prophase • Nuclear membrane dissolves • Chromosomes become visible

  19. Metaphase • Chromosomes align on the equator • Spindle fibers form and attach to centromere

  20. Anaphase • Centromeres break • Chromatids move toward the poles as spindle fibers shorten

  21. Telophase • Nuclear envelope forms • Cleavage furrow in animals • Cell plate in plants • Daughter cells form when Cytokinesis (cell splits into two) occurs

  22. Cleavage Furrow

  23. Cell Plate

  24. When Mitosis goes bad • Cell Cycle checkpoints don’t work properly • Cell can divide when it shouldn’t • Cell can mutate • A benign (harmless) tumor can form • Cancer may develop

  25. Cell Cycle CheckPoints

  26. What is Cancer? • Named for organ or tissue where its found • Cells that divide out of control due to a mutation in the DNA • These “out of control” cells can destroy/invade normal cells and tissues • Cancer can spread from a malignant (harmful) tumor • Metastasis is cancer cells that have spread

  27. Figure 12-17x1 Breast cancer cell

  28. Lymph vessels Tumor Glandular tissue Metastasis A tumor grows from a single cancer cell. Cancer cells invade neighboring tissue. Cancer cells spread through lymph and blood vessels to other parts of the body Figure 8.9

  29. Common Types of Cancer

  30. Cancer Treatment • Radiation can be used for skin cancer • Chemotherapy involves drugs that stop Mitosis throughout the body • Chemotherapy drugs not only try to kill cancer cells but it makes wounds slower to heal, hair to be lost, immune system to be weakened

  31. Cancer “Caution” Signs • Change in potty habits • A sore that does not heal • Unusual bleeding or discharge • Thickening of tissue or new lump • Indigestion • Obvious changes to moles or warts • Nagging cough that lasts for a month or more

  32. Cancer Prevention-what YOU can do • Not smoking • Limiting time in the sun • Eating high-fiber, low-fat diet • Visit Doctor regularly • Perform regular self-examinations

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