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CELL CYCLE
11-11-08
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 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

Cells Alive!
 http://www.cellsalive.com/cell_cycle.htm