1. The Cell Cycle: Interphase, Mitosis and Cytokinesis
Gridlock Rules

2. Introduction: You should be able to:
Define interphase, mitosis and cytokinesis
Describe the cell cycle
Discuss the events and significance of mitosis.

3. Definitions:
Interphase: the period during the cell cycle between cell divisions, during which DNA replication and protein synthesis take place.
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4. Definitions (cont).
Mitosis: is the process by which the nucleus of a cell is divided into two nuclei, each with the same number and kinds of chromosomes as the parent cell.
Cytokinesis: is the process by which the cytoplasm divides forming two distinct cells.

5. Review:
Chromosomes: are structures in the cell that contain genetic information that is passed from one generation to the next.

6. Chromosomes: Only visible during mitosis
Made up of chromatin (DNA and proteins)
Cells of every organism have a specific number of chromosomes. (Goldfish=94, Humans=46)

7. Chromosome Structure
Each chromosome is made up of two identical chromatids joined at a specific site called the centromere.

8. The Cell Cycle
Interphase
Mitosis
Cytokinesis

9. Interphase Period “in between” cell divisions
Usually longer than other phases
Chromosomes are unraveled, the DNA is at work
3 main parts of interphase
G1 , S , G2

10. Interphase (cont.) G1- Cell growth and development
S- DNA replication & Protein Synthesis
G2- Organelle replication

11. Interphase
Animal Plant

12. Mitosis
Prophase
Metaphase
Anaphase
Telophase

13. Prophase Longest phase of mitosis
Chromosomes begin to form visible coils
Centrioles move to opposite ends of the cell (no centrioles in plant cells)
Spindle fibers form
Nucleolus disappears
Nuclear envelope breaks down

14. Prophase
Animal Plant

15. Metaphase Shortest phase of mitosis Chromosomes are fully coiled
Chromosomes line up at the middle of the cell
Spindle fibers form star-like patterns around the centrioles called asters

16. Metaphase
Animal Plant

17. Anaphase Begins when the sister chromatids begin to separate
Chromatids move to opposite ends of the cell
Anaphase ends when the chromatids stop moving

18. Anaphase
Animal Plant

19. Telophase Chromatids uncoil Two nuclear envelopes form
Spindle fibers disappear
Nucleoli become visible
Telophase is the end of mitosis, but not the end of cell division.

20. Telophase
Animal Plant

21. Animal Cell Mitosis I P M T A

22. Plant Cell Mitosis I P M A T

23. Cytokinesis Immediately following mitosis Cytoplasm divides
Two separate cells are formed

24. Cytokinesis
Animal

25. Cell Cycle Summary Interphase Mitosis: Cytokinesis Prophase Metaphase
Anaphase
Telophase
Cytokinesis

26. Plant Vs. Animal Cellular Division
Animal Cells have centrioles, Plant cells do not

27. Plant Vs. Animal Cellular Division
Animal cells form a cleavage furrow during cytokinesis (cell membrane pinches in the middle)

28. Plant Vs. Animal Cellular Division
Plants generate a cell plate at the equator during anaphase.
Cell plate is filled with cellulose to make a new cell wall.

29. Animal Cell
Plant Cell
Cleavage Furrow
Cell Plate

30. Prokaryote Vs. Eukaryote Cell Division
Prokaryotes divide by process called Binary Fission
They only have one chromosome called a nucleoid
Nucleoid is copied and separated during division

31. Prokaryote Vs. Eukaryote Cell Division
Binary fission produces 2 identical daughter cells
Can happen as fast as every 20 minutes.

32. Nucleoid

33. Prokaryote Vs. Eukaryote Cell Division
Eukaryotes produces 2 or more chromosomes
Organelles must be evenly separated into the new cells
Slower process (Human cells take over 16 hours to divide)

34. Cancer Cancer is the uncontrolled growth and division of cells
group of cancer cells is a tumor
As the tumor grows, it destroys neighboring cells and tissues

35. Cancer Two types of tumors
. Benign- cells grow in a ball, does not invade other cells.
. Malignant- unorganized growth that can spread to other parts of the body or tissues.

36. Cancer Cells