1. M phase

2. DNA at different phases
histone
nucleosome
chromatin
chromosome

3. DNA at different phases
Chromatin
- DNA + protein
- before cell division (M phase)
Chromosome
- condensed chromatin during cell division
Sister Chromatid
- each individual double helix

9. FYI..
Body cells (autosomes/somatic cells) have 46 chromosomes or 23 pairs
Diploid – 2n
Sex cells (gametes) have 23 chromosomes
Haploid - n

10. M phase
Mitosis (nuclear division)
Cytokinesis (cytoplasmic division)

12. Mitosis Nuclear division Cell growth stops
Produces 2 similar daughter cells (2n)
Asexual reproduction
1-2 hrs only
Metaphase Checkpoint

14. Stages of Mitosis
Metaphase
Prophase
Anaphase
Cytokinesis
Telophase

15. Prophase Chromatin thickens into chromosomes
Nuclear membrane and nucleolus disintegrates
Mitotic spindle forms
Centrosome pairs move to opposite ends

16. Prophase

17. Prophase

18. Metaphase

19. Chromosomes at metaphase plate
Centrosomes at opposite poles
Kinetochores attached to microtubules

20. Secrets on how chromosomes move..
Centrosome
Aster
Sister chromatids
Metaphase Plate
Kinetochores
Overlapping nonkinetochore microtubules
Kinetochores microtubules
Chromosomes
Microtubules
0.5 µm
1 µm
Figure 12.7

21. Secrets..
Kinetochore
Spindle pole

22. microtubule

23. Anaphase

24. Centromeres divide
Chromatids now chromosomes
Kinetochore microtubules shorten Chromosomes separate and move
Nonkinetochore microtubules lengthen
End: chromosomes at 2 poles

26. Motor protein

27. Telophase

28. Chromosomes arrive at opposite poles
Spindle fibers disintegrate
Nuclear membrane reforms & Nucleolus reappears
Chromatin fibers become less tightly coiled

29. Cytokinesis

30. Cytoplasm divides
Animals: cleavage furrow divides cytoplasm
Plant cells: cell plate
Two daughter cells

31. Cell pinches inward

33. Cell Plate Formation Vesicles forming cell plate Wall of patent cell
Daughter cells
1 µm
Vesicles forming cell plate
Wall of patent cell
Cell plate
New cell wall

34. Mitosis in an Animal Cell

36. Cleavage furrow
Centrioles
ANIMAL CELL

37. Cell plate No
centrioles
PLANT CELL

38. Result of Cell Cycle two new daughter cells net gain of only one cell
identical to the parent cell in chromosome number and chromosome type
net gain of only one cell
two new daughter cells will enter interphase and the cycle will continue… 

39. Cell Cycle