Asexual Reproduction

1. Asexual Reproduction 3 Questions will be asked in 3 minutes. Write a brief answer for each one. Be prepared to share your answer. Mitosis 1

2. Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals? 3:00

3. 2:00 WHY DO CELLS DIVIDE? Give me 2 reasons.

4. 1:00 HOW will YOU remember IPMAT?

5. TIME’s UP!

6. Genetics:Mitotic Cell Division

7. How do little elephants grow up to be BIG elephants?

8. Why do animals shed their skin?

9. The process of asexual reproduction begins after a sperm fertilizes an egg.

10. Where it all began… You started as a cell smaller than a period at the end of a sentence…

11. And now look at you… How did you get from there to here?

12. Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. Cells that reproduce by asexual reproduction reproduce constantly.

14. BUT FIRST…. Use your book and define the following terms in your notes. You have 5 minutes. 1) Page 244CHROMOSOME (it is not in bold, so read carefully) CHROMATID 2)Draw a chromatid. 3) Page 245CENTROMERE 4) Page 247SPINDLE

15. Chromosomes • Strands of DNA • Each human has 23 pair (diploid or 2n) • One from your mother • One from your father

16. Chromosome DNA molecule with attached proteins Sister chromatids One from Mom One from Dad

17. Chromosome number • Every organism has its own specific number of chromosomes Examples:Human = 46 chromosomes or 23 pairs Dog = 78 chromosomes or 39 pairs Goldfish = 94 chromosomes or 47 pairs Lettuce = 18 chromosomes or 9 pairs

18. Phases and Sub-phases of Cell Division a. G1 1. Interphase b. S c. G2 1. Prophase Nuclear division 2. Metaphase 3. Anaphase 2. Mitosis 4. Telophase b. Cytokinesis From the Virtual Cell Biology Classroom on ScienceProfOnline.com

20. Control of the Cell Cycle

21. Interphase • Prior & After Mitosis • G1 period • 90% of cell life spent here • Cell goes about it’s business • S period • DNA is duplicated • G2 period • Cell prepares to divide • Cannot see DNA- uncoiled as chromatin

22. Animated Mitosis Cycle • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis

23. Interphaseoccurs before mitosis begins • Chromosomes are duplicated (# doubles) • Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sisterchromosome) change to sister chromatids at end of this phase • Cells are usually in interphase CELL MEMBRANE Nucleus Cytoplasm

24. Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

26. Prophase 1st step in Mitosis • Mitosis begins (cell begins to divide) • Centrioles (or poles) appear and begin to move to opposite end of the cell. • Spindle fibersform between the poles. • Chromosomes coil up and become visible, thicker, and shorter • Nuclear envelopedisappears Centrioles Spindle fibers

27. Prophase 1st step in Mitosis Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

28. Metaphase 2nd step in Mitosis • Metaphase = Middle • Chromosomes attach to the spindle fibers. • Chromosomes move to the middle of the cell.

29. Metaphase Metaphase 2nd step in Mitosis Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

30. Anaphase 3rd step in Mitosis • Chromosomes separate and begin to move to opposite ends of the cell. • Spindle fibers pull chromosomes to opposite poles

31. Anaphase 3rd step in Mitosis Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

32. Telophase4th step in Mitosis • Chromosomes uncoil and appear as threads rather than rods. • Nuclear membrane reforms around chromosomes. • Two new nuclei form. • Spindle fibers disappear • Mitosis ends.

33. Telophase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

34. Cytokinesisoccurs after mitosis • Cell membrane moves inward to create two daughtercells – each with its own nucleuswith identical chromosomes. • Cytoplasm divides. • After mitosis and cytokinesis, the cell returns to Interphase to continue to grow and perform regular cell activities

36. Animal Mitosis -- Review

37. Plant Mitosis -- Review

38. Summary of Mitosis • Prophase: • Chromosomes condense • Nuclear envelope disappears • centrosomes move to opposite sides of the cell • Spindle forms and attaches to centromeres on the chromosomes • Metaphase • Chromosomes lined up on equator of spindle • centrosomes at opposite ends of cell • Anaphase • Centromeres divide: each 2-chromatid chromosome becomes two 1-chromatid chromosomes • Chromosomes pulled to opposite poles by the spindle • Telophase • Chromosomes de-condense • Nuclear envelope reappears • Cytokinesis: the cytoplasm is divided into 2 cells

41. DNA replication, cell grows and replicates organelles DNA copies itself; chromatin Nuclear envelope disappears, spindle fibers form Chromosomes coil up Chromosomes line up in the middle Spindle fibers connect to chromosomes Spindle fibers pull chromosome copies apart to opposite poles Chromosome copies divide and move apart Nuclear envelopes reform, 2 new nuclei are formed, spindle fibers disappear Chromosomes uncoil back into chromatin Division of the rest of the cell: cytoplasm and organelles Chromatin

42. Cell Cycle

43. MitosisAnimation COOL LINKS http://www.youtube.com/watch?v=m73i1Zk8EA0&feature=youtube_gdata_player http://www.youtube.com/watch?v=DD3IQknCEdc&feature=youtube_gdata_player http://www.youtube.com/watch?v=XSKh-GLQn4E&feature=youtube_gdata_player http://www.youtube.com/watch?v=eTvaGPcYNF8&feature=youtube_gdata_player