1. The Cell Cycle & Mitosis
Notes: The Cell Cycle and Mitosis
The Cell Cycle & Mitosis

2. Mitosis Intro Discussion
Why is mitosis important…???
What would happen if cells never divided?
Since we know cells do divide, what preparations do you think each cell needs to take for a division event?

3. Prokaryotic Cell Division
Notes: The Cell Cycle and Mitosis
Prokaryotic Cell Division
Prokaryote: simple, usually bacterial cell
Binary Fission: division of a prokaryotic cell into two new identical cells
Electron Micrograph of Escherichia coli with a Conjugation Pilus
FYI: Bacterial conjugation is NOT a sexual process, just a transfer of genes.

4. Binary Fission in Action
3 Steps
DNA is copied and attaches to cell membrane
Cell doubles in size
Cell divides; each cell gets a circle of DNA
Video Clip

5. A cyclical pattern of eukaryotic cell life events.
The Cell Cycle
A cyclical pattern of eukaryotic cell life events.

6. Investigating Interphase
The time between cell divisions
A cell spends most of its lifetime in this phase
Phases of Interphase
G1: Cell growth
S: Synthesis of new DNA (the old stuff is copied)
G2: Time for final preparations before cell divides
FYI: Cell exits cycle &/or dies at G0

7. The M Phase: Mitosis
Consists of four sub-phases of the cell cycle that:
Divide the cell nucleus
Equally partition (share) chromosomes
Create two new “daughter cells”

8. Mitosis the Movie

9. Prophase Phase 1 of Mitosis DNA tightly coils into chromosomes
Like chromosomes attach at centromere
Nucleolus and nuclear membrane disappear
Spindle begins to form

10. Prophase

11. Metaphase Phase 2 of Mitosis
Chromosomes can be stained and easily seen
Chromosomes on kinetochore fibers line up across the center of the spindle
FYI: A kinetochore is a spindle fiber that is thicker than the other fibers and it is designed so that the centromere can attach.

12. Metaphase

13. Anaphase Phase 3 of Mitosis
Paired chromosomes separate at the centromere
Chromatids are pulled by the spindle to opposite ends of the cell

14. Anaphase

15. Telophase Phase 4 of Mitosis Spindle disappears
Nuclear Membrane reforms
Cytokinesis (cell division) occurs
Chromatids in the new cells relax into chromatin

16. Notes: The Cell Cycle and Mitosis
Telophase

17. Cytokinesis Cytokinesis is the division of the cell
Happens late in telophase
Cell divides at the cleavage furrow where the cell membrane pinches in
In plants, the cell divides at the cell plate where the cell wall is forming

18. Final Product of Mitosis
The final product of mitosis is two daughter cells, each containing:
Identical copies of parent chromosomes
Roughly ½ of the parent cell’s cytoplasm and organelles
Online Mitosis Tutorial
Length of Cell Cycle and Mitosis Phases Tutorial