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

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

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

4. HOW will YOU remember IPMAT?
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
Three reasons why cells reproduce by asexual reproduction: Growth Repair 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…. 2)Draw a chromatid.
Use your book and define the following terms in your notes. You have 5 minutes.
1) Page 244 CHROMOSOME (it is not in bold, so read carefully)
CHROMATID
2)Draw a chromatid.
3) Page 245 CENTROMERE
4) Page 247 SPINDLE

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 S period G2 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. Interphase occurs before mitosis begins
Chromosomes are duplicated (# doubles)
Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) 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:

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 fibers form between the poles.
Chromosomes coil up and become visible, thicker, and shorter
Nuclear envelope disappears
Centrioles
Spindle fibers

27. Prophase 1st step in Mitosis
Plant Cell
Animal Cell
Spindle fibers
Centrioles
Photographs from:

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

29. Metaphase 2nd step in Mitosis
Plant Cell
Animal Cell
Photographs from:

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
Plant Cell
Animal Cell
Photographs from:

32. Telophase 4th 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:

34. Cytokinesis occurs after mitosis
Cell membrane moves inward to create two daughter cells – each with its own nucleus with 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
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

37. Plant Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

38. Summary of Mitosis Prophase: Metaphase Anaphase Telophase
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

40. Chromosome Appearance & Location
Phase
Chromosome Appearance & Location
Important Events
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

41. Chromosome Appearance & Location
Phase
Chromosome Appearance & Location
Important Events
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
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. COOL LINKS Mitosis Animation