Cell Life Cycle- 2 major stages

1. Cell Life Cycle- 2 major stages • A. __________ • What happens? • B. _________ What happens?

2. Interphase – Between Mitotic phases • How long (relatively speaking) is this stage? • What does the DNA look like at this stage?

3. What happens at the very end of interphase?

4. Mitosis • An highly organized method of replication creating identical daughter cells from one parent cell • When a cell loses control of mitosis, a CANCER may occur

5. 4 Stages of Mitosis • Prophase • Metaphase • Anaphase • Telophase

6. Mitosis Animated

7. Prophase Chromatid • EVENTS: • Nuclear membrane breaks down • Chromatin coils into chromosomes • Centrioles move apart • Spindle fibres stretch across the cell • Chromosomes eventually attach to spindle fibres

9. ONION ROOT TIP

10. Metaphase • Spindle fibres pull the chromsomes to line up along the equator of the cell

13. Anaphase • Chromatids move to opposite poles of the cell

15. Telophase • The reverse of prophase • cell membrane starts to pinch • nuclear membrane forms around each set of chromosomes • Each has its own nucleus (and the cell is ready to divide)

16. Chromosomes at each end of the pole • Spindles fibres disappear

18. Cytokinesis • In late telophase, the rest of the organelles … great animation of mitosis

26. Checkpoints in the cell cycle will prevent division if: • If the cell is short of nutrients • If the DNA within the nucleus has not been replicated • If the DNA is damaged

27. Mutations in genes involving checkpoints can result in an uncontrolled cell cycle. The result of uncontrolled cell division can = cancer. • Cancer cells have large, abnormal nuclei • Cancer cells are not specialized, so they serve no function • Cancer cells attract blood vessels and grow into tumours. • Cells from tumours can break away to other areas of the body

28. Compare and Contrast Asexual and Sexual Reproduction -including the outcomes of mitosis and meiosis -including methods of asexual and sexual reproduction

29. Asexual Reproduction • Produces genetically identical offspring • Requires only one parent • Is fast and efficient • Does NOT increase the genetic variation in the species

30. Sexual Reproduction • Produces genetically unique offspring (new combinations) • Requires 2 parents • Increases the genetic variation of the species

31. Methods of Asexual Reproduction • Binary fission

32. Regeneration

34. Fragmentation

35. Vegetative Reproduction

36. Grafting • Insert a scion (twig) of desired plant onto a stock of another • Scion will continue to grow as the desired plant

37. Spore Formation • Bacteria • Microorganisms • Fungi

38. Budding • Offspring grows attached to parent • Falls off when mature

39. Human Assisted Cloning: • More complex plants and animals have lost the ability to clone themselves because their cells have become too specialized.

40. However, scientists have discovered how to assist the creation of clones in complex organisms.

41. Human Assisted Cloning – how it’s done:

43. Scientists can clone complex organisims for two reasons: • 1. Reproductive Cloning: To produce a genetically identical organism that because it has desirable characteristics.

44. 2. Therapeutic cloning: To create STEM cells (embryonic) for use in cell therapy. The stem cells can correct health problems, because stem cells can develop into any one of our 200 types of body cells!

45. Embryonic Stem cells can develop into ANY kind of cell in our body.

46. Therapeutic cloning - to correct health problems • Uses stem cells which can be used to replace cells damaged from injuries or disease

47. What can we use use stem cells for?

48. Diabetes, spinal injuries, Parkinson’s disease are only a few that can benefit from stem cell therapy Animation of developent from egg to fetus (includes stem cells)

49. Why is the use of stem cells considered controversial?