This document summarizes the key stages and types of cell division. It describes mitosis in somatic cells, which produces two identical diploid cells, and meiosis in germ cells, which produces four haploid gametes. The cell cycle is outlined, including the interphase consisting of G1, S, and G2 phases, and the five stages of mitosis: prophase, metaphase, anaphase, telophase, and cytokinesis. Plant cell telophase involves formation of a cell plate rather than cleavage.

1. • Mitosis

2. Types of cells
• Somatic cell :
 Diploid set of chromosomes (2n)
 Ex. 46 chromosomes in human somatic cell
Ex. Skin cells
 Division by : Mitosis , produce 2 identical diploid cells

3. • Germinal cells
 Diploid set of chromosomes (2n)
 Found in gonads of human
 Ex. Testes of man, Ovaries of woman.
 Division by : Meiosis , produce 4 haploid cells ( Gametic cells )

4. • Gametic cells
 Produced from meiotic division of germinal cells
 It has a haploid set of chromosomes (n)
 Ex. Sperms in man ( 23 chromosomes)
 Ovum in woman ( 23 chromosomes)

5. Cell Cycle
18 hrs
1 hr
19 hrs

6. Interphase:
2N
is the period between two successive cell divisions, or the
preparation stage of mitotic division.
1. Growth phase 1 (G1):
Rapid RNA and
protein synthesis.
100%

7. 2N
2. Synthesis phase (S):
 Synthesis of DNA occurs inside the nucleus,
while histones are synthesized in the
cytoplasm.
 Interference of histones with DNA
molecules occurs in the nucleus to complete
the chromosome structure.
 DNA and histone synthesis.
 Duplication of chromosomes
without separation.
1. Growth phase 1 (G1):
Rapid RNA and
protein synthesis.
150%

8. 2. Synthesis phase (S):
 Synthesis of DNA occurs inside the nucleus,
while histones are synthesized in the
cytoplasm.
 Interference of histones with DNA
molecules occurs in the nucleus to complete
the chromosome structure.
 DNA and histone synthesis.
 Duplication of chromosomes
without separation.

9. 3. Growth phase 2 (G2):
The period between the end of
DNA synthesis and the beginning
of prophase.

10. 3. Growth phase 2 (G2):
The period between the end of
DNA synthesis and the beginning
of prophase.
The cell ready to inter the division now
2N
200%

11. Cell Cycle
18 hrs
1 hr
19 hrs
Mit sis

12. The centrosome is divided into 2 centrioles
Formation of Spindle fibers
Break down of nuclear envelope and Nucleolus
Prophase :

13. Metaphase :
Each centriole moves toward a corresponding pole
Elongation of Spindle Fibers

14. Metaphase :
Elongation of Spindle Fibers
Each centriole moves toward a corresponding pole
Arrangment of chromosomes at the equatorial plate

15. Anaphase :
Shortening of spindle Fibers
Splitting of centromeres
2 groups of chormatids are formed in each side

16. Anaphase :
Shortening of spindle Fibers
Splitting of centromeres
2 groups of chormatids are formed in each side

17. Telophase :
Cytokinasis :
Splitting of cytoplasm

18. Telophase :
Cytokinesis completed
Formation of 2 diploid daughter cells
Reformation of nuclear envelope and nucleolus
(2n)
(2n)

19. Telophase of plant cell
Formation of
Cell Plate

20. 2N 2N
Telophase of plant cell
Formation of
Cell Plate
Two
Diploid
Cells