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Cell Reproduction Unit

Cell Reproduction Unit. Chromosome Structure. - chromosome = a long continuous thread of DNA that consists of numerous genes with regulatory information coiled around proteins in compact structures. Chromosome Structure. - DNA wraps around proteins (called histones) to become compact.

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Cell Reproduction Unit

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  1. Cell Reproduction Unit

  2. Chromosome Structure - chromosome = a long continuous thread of DNA that consists of numerous genes with regulatory information coiled around proteins in compact structures

  3. Chromosome Structure - DNA wraps around proteins (called histones) to become compact

  4. Chromosome Formation

  5. Chromosome Structure (cont) Chromatid Centromere

  6. Cell Cycle = the regular pattern of growth, DNA duplication, and cell division that occurs in cells

  7. Cell Cycle - results in two cells (daughter cells) identical to one another - made up of 5 Phases

  8. Cell Cycle (cont) 1) G1 Phase = cell growth 2) S Phase = DNA is copied 3) G2 Phase = cell prepares for cell division Together Phases 1-3 are called Interphase

  9. Cell Cycle (cont) 4) M Phase (Mitosis) - division of the nucleus 5) C Phase (Cytokinesis) - division of the cytoplasm

  10. Cell Cycle (cont) Sequence of the Cell Cycle G1 S G2 M C

  11. Cell Cycle (cont)

  12. Cell Cycle (cont)

  13. Mitosis = division of the nucleus and its contents - discovered by Walther Flemming in 1882

  14. Phases of Mitosis

  15. 1) Prophase - DNA coils to become chromosomes - nuclear membrane disappears - microtubules called spindle fibers grow from centrioles to center of cell

  16. 1) Prophase (cont) Spindle Fibers: 2 Types 1) Kinetochore Fibers – attach to chromosomes (at centromere) 2) Polar Fibers – spread throughout cell

  17. Prophase Centrioles Nucleus with Chromosomes Spindle Fibers

  18. Late Prophase Kinetochore Fibers Polar Fibers

  19. 2) Metaphase - chromosomes line up in center

  20. Metaphase

  21. 3) Anaphase - chromosomes pull apart and move to opposite sides of cell

  22. Anaphase

  23. 4) Telophase - chromosomes uncoil - nuclear membrane reforms

  24. Telophase Chromosomes Uncoil New Nuclear Membrane Forms

  25. Phases of Mitosis

  26. How do you remember the order of the phases of Mitosis? Just remember this phrase……….

  27. PMAT PEE MATT P = Prophae M = Metaphase A = Anaphase T = Telophase

  28. Cytokinesis - cell membrane forms a cleavage furrow and cytoplasm divides - in plants, a cell plate forms between each cell

  29. Cytokinesis Cleavage Furrow

  30. Cell Plate

  31. Regulation of Cell Division - controlled by external and internal factors - External Factors 1) cell to cell contact 2) growth factors

  32. Cell to Cell Contact

  33. Regulation of Cell Division (cont) Growth Factors – Examples - Platelets

  34. Regulation of Cell Division (cont) Growth Factors – Examples - Erythropoietin (stimulates red blood cell production)

  35. Regulation of Cell Division (cont) - Internal Factors - enzymes and proteins released by the cell

  36. Regulation of Cell Division (cont) - apoptosis = programmed cell death Webbed Fingers

  37. Apoptosis – Leaves in Fall

  38. Incomplete Apoptosis

  39. Cancer cells form tumors that may metastasize to other parts of the body A healthy cell may become a cancer cell if certain genes are damaged Cancer Cell Normal Cell Bloodstream

  40. Cancer cells form tumors that may metastasize to other parts of the body Cancer cells divide more often than do healthy cells and may form disorganized clumps called tumors

  41. Cancer cells form tumors that may metastasize to other parts of the body Sometimes cancer cells break away from the tumor. They can be carried in the bloodstream to other parts of the body where they form new tumors.

  42. According to the American Cancer Society, skin cancer is the most common of all cancers. This cancerous mole is an example of a skin cancer, which may metastasize quickly.

  43. ABCD Rule (for moles, etc) Mnemonic to help remember what to look for A = Asymmetry (irregular shape) B = Border is irregular shape C= Color change (changing or many colors) D = Dimension (1/4 in or less) **other key signs to look for: New growth, changes in growth, painful feeling

  44. Look for the ABCD Rule in this mole?

  45. Why is sex with someone else better than sex by yourself?

  46. Asexual Reproduction = reproduction of offspring from one parent - offspring are genetically identical to the parent …this is a BAD thing

  47. Sexual Reproduction = reproduction of offspring from two parents - offspring are genetically different from the parents …this is a GOOD thing

  48. Example Nut Disease in Squirrels

  49. Some eukaryotic cells divide by mitosis

  50. Some organisms can reproduce by asexual or sexual reproduction (depends on conditions)

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