The document summarizes the cell cycle process. It discusses that the cell cycle involves a period of growth, DNA replication, and cell division. It is comprised of two main phases: interphase and mitosis. Interphase includes the G1, S, and G2 phases where the cell grows in size, DNA is replicated, and prepares for division. Mitosis is the phase where the cell undergoes division and separates the duplicated DNA between the two new daughter cells. The length of the cell cycle phases can vary depending on the type of cell.

1. Cell cycle
Prepared by Shajee Leghari
Roll No 14
BS Botany

2. Cell cycle
• Definition
1- The cell undergo sequence of changes, which involve
period of growth, replication of DNA,followed by cell division.
This sequence of changes is called cell cycle.
2-The period from the time a cell is produced until its
complete its division is called cell cycle.

3. Why a cell divide??
• When an organism grow it needs more cells
• New cell replaced old and damaged cells
• Cell divide in reproduction
I. A SEXUAL…..Offspring is identical to parents
II. SEXUAL….Offspring are combination of both parents

4. Phases of cell cycle
There are two phases of cell cycle
Interphase
Mitosis

5. INTERPHASE
 Period of non apparent division
 Misleadingly called resting phase
 Period of great metabolic activity
 Further divided into 3 stages
I. G1
II. S
III.G2

6. G1 PHASE
 Period of extensive metabolic activity
 Cell grow in size
 Specific enzymes can be synthesized
 DNA base units are accumulated
 Its also called post mitotic phase

7. G0 phase
 Non dividing, differentiated state
 Most human cells in G0 phase
E.g. eye cells, nerve cells
 Cell maintain speclized characteristics
But not divide

8. S phase
• DNA is synthesized
• Chromosome number is doubled

9. G2 phase
 Its also called premitotic phase
 Specific protein is synthesized
 RNA microtubules synthesized
 Energy storage for chromosome
movement
 Mitotic specific protein is
synthesized

10. Specific check points
 Determine the fate of
new phase according to
cell internal makeup

11. Length of phases

12. Length of cell cycle phases in human liver cell

13. Length cell cycle phases in Embryogenic cells

14. THANK YOU