1. CELL CYCLE 11-11-08

2. Cell Growth  Body cells spend most of its life growing and doing work. But it can only grow so large.  Body cells consist of skin, stomach, & blood cells  Growth in an organism occurs because of adding cells.

3. Cell Division  Cells will eventually reach a stage in their cell cycle and will divide.  This process of cell division is called MITOSIS.  Mitosis- a process of cell division in body cells.  One parent cell produces two daughter cells.

4. Cell Cycle  A series of events a cell goes through as it divides and grows.  Interphase- time between cell divisions when the cell is growing and working.  The cell is in interphase for 99% of its life.  The cell is undergoing mitosis (dividing) the rest of the time  The cell cycle is divided into 4 phases

5. Cell Cycle Phases 1. G 1 phase- Cell Growth: “Gap” time in which cell grows the most; makes proteins. 2. S phase- DNA Replication: Chromosomes are copied; begins to prepare for mitosis

6. Cell Cycle Phases 3. G 2 phase- Prep for Mitosis: “Gap” Shortest of 3 interphase phases - organelles and molecules needed for mitosis are produced 4. M phase- Mitosis stages and cytokinesis

8. Checkpoints  There are 3 checkpoints in the cycle 1. G1 Checkpoint: If the cell is big enough and the environment is suitable. 2. G2 Checkpoint: If DNA has replicated, the cell is big enough, and the environment is suitable. 3. Metaphase checkpoint: If chromosomes are aligned at the spindle

9.  Cells Alive!  http://www.cellsalive.com/cell_cycle.htm http://www.cellsalive.com/cell_cycle.htm