1. THE CELL CYCLE

2. All organisms have a life cycle:
birth growth reproduction death

3. Within all organisms, cells are also “born”, grow, reproduce/divide, and die.
CELL TYPE
LIFE SPAN
Skin cell
2 weeks
Red blood cell
4 months
Liver cell
days
Lining of the intestine
4-5 days
Smooth muscle
16 years

4. As old cells die, new cells are produced.
New cells are produced by cell division.
One cell divides to form two new cells.
cell
division
one
cell
two
identical
cells

5. Why are new cells produced?
To replace old
or dead cells
To replace cells
destroyed by injury
Skin cells

6. Cells divide to produce new cells
for growth and development.

7. Cells divide to produce a new individual
--- asexual reproduction

8. YOU are here because of cell division.
The one cell
divided to produce
2, then 4,
then 8, 16, 32, …..
cells
You began life
as one cell
And continued to
divide…
zygote

9. The cell cycle A repeating sequence of cellular growth, DNA replication, and cell division .

10. The cell cycle can be divided into five stages:
1. Gap 1(G1):
The cell carries out its normal functions.
Muscle cells---
contract to move joints
Intestinal cells---
absorb nutrients

11. A cell spends most of its time in the G1 stage.
During the G1 stage:
Cells also increase in size,
and organelles increase in number.
A cell spends most of its time in the G1 stage.

12. CELL CYCLE G1

13. 2. Synthesis stage (S): The cell copies its DNA during this stage.
At the end of this stage,
the nucleus contains
two complete sets of DNA.

14. CELL CYCLE S G1
DNA Is replicated

15. 3. Gap 2 (G2) : The cell continues to carry out its normal functions,
and additional growth occurs.

16. CELL CYCLE S G1 G2 interphase. The G1, S, and G2 stages
DNA Is replicated G2
The G1, S, and G2 stages
are collectively known as
interphase.

17. 4. Mitosis: The division of the cell nucleus
into two identical nuclei.

18. CELL CYCLE
CELL
DIVISION

19. 5. Cytokinesis:
The division of the cytoplasm.

20. CELL CYCLE S G1
DNA Is replicated G2
CELL
DIVISION

21. After the cell undergoes mitosis and cytokinesis, the two new cells produced are identical to the original cell.