1. Homework from last class:
Complete storyboard for mitosis project
Bring materials and camera 1

2. Note:
A blue box surround the notes you should copy 2

3. Cytokinesis, Checkpoints in the Cell Cycle, and Cancer
Chapter 5.1 pp 3

4. Cytokinesis
cytokinesis: the final stage of the cell cycle; separates the 2 nuclei and cell contents into 2 daughter cells.
New cells are identical to the parent cell.
Parent cell (in telophase)
2 identical daughter cells 4

5. Animal cells – cell membrane pinches together to divide the cell’s cytoplasm and organelles
Plant cells – a cell plate forms along the centre of the cell to divide the cell into 2 daughter cells 5

6. Checkpoints in the Cell Cycle
Activities in the cell cycle are monitored and controlled at specific stages (checkpoints).
Proteins at these checkpoints monitor cell activities
send info to nucleus
instructs the cell whether or not to divide
Cells will not divide if:
Not enough nutrients to support cell growth
DNA in nucleus has not been replicated
DNA is damaged 6

7. Checkpoints in the Cell Cycle7

8. Cancer
If a mutation occurs in a gene producing the instructions for a checkpoint protein, cell cycle control will be lost  can lead to uncontrolled division (cancer) 8

9. Healthy cells stop dividing when they receive messages from neighbouring cells; cancer cells do not respond to messages from nearby cells  continue to divide  tumour
p. 161 9