CELL CYCLE11-11-08

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.

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.

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

Cell Cycle Phases

1. G1 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

Cell Cycle Phases

3. G2 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

Checkpoints

There are 3 checkpoints in the cycle1. 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

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