5. MITOSIS
• Mitosis is a process where a
cell divides resulting in 2
identical cell.
• Each cell contains the same
number of chromosomes and
genetic content
6.
7. HISTORY
•Mitosis was first discovered in plant cells by
strasburger(1875).
•Later on W. Flemming (1879) discovered it in animal
cells.
•The term mitosis was coined by Flemming (1882).
8. OCCURRENCE
• The cells undergoing mitosis are called mitocytes .
• In plants, the mitocytes are mostly meristematic cells.
• In animals , the mitocytes are stem cells , germinal epithelium
and embryonic cells.
• It also occurs during regeneration.
• Root tip is the best material to study mitosis.
10. CELL CYCLE
• A typical cell goes through a process of growth,
development and reproduction called the cell cycle.
• The longest phase in cell cycle in interphase.
• The 3 stages of interphase are called G1, S, G2
11.
12.
13.
14. CELL CYCLE STAGES
• Two stages
1. Karyokinesis (Prophase, metaphase, anaphase
and telophase)
2. Cytokinesis
16. PROPHASE
• It is the 1st phase of mitosis.
• The cell begins the division process.
• The nucleolus disappear
• The nuclear membrane breaks apart .
• The chromatin present in the nucleus
condenses to form chromosomes in this phase.
• The centrosomes begin to move apart
from each other.
• Later these centrosomes also start the
formation of spindle fibers or microtubules.
17.
18. METAPHASE
The 2nd phase of mitosis.
Chromosomes organized along
equatorial plane.
Formation of spindle fibers
Chromosomes attached to spindle
fibers with the help of kinetochore
present on centromere of chromosomes.
Centrosomes align at opposite
ends of the cell.
19.
20. ANAPHASE
• The third phase of mitosis.
• Diploid sets of daughter
chromosomes separate.
• Each chromatid behaves like
an individual chromosomes.
• By the end of Anaphase the
2 ends of the cells have
equal no of chromosomes.
• They are pushed and pulled
towards opposite poles of the cell by the spindle fibers.
21.
22. TELOPHASE
• The nuclear membrane and
nucleoli (nuclear reform).
• Spindle fibers disappear and 2
daughter nuclei are formed.
• The chromosomes becomes
less condensed.
• Nuclear membrane reappear.
• Cytokinesis is nearly complete.
• The cell plate begins to form.
• The cell prepares for final division.
23.
24. CYTOKINESIS
• The final stage of mitosis.
• Division of cytoplasm of mother cell.
• The cytoplasm, organelles and nuclear material are evently split and two
new cells are formed.
• The cleavage of cell into halves.
• Each half is called a daughter cell.
• Each daughter cell has the same number of chromosomes present in parent
cell
• The 2 new cells –each exactly like the other are called daughter cells.
25. METHODS OF CYTOKINESIS
•It takes place by 2 different methods
1. Cell plate method.
2. Cleavage or cell furrowing method.
26.
27. Cell plate cytokinesis
• It occur in plant cell.
• The Golgi vesicle fuse at the
centre to form barrel shaped
phragmoplast.
• The contents of phragmoplast
solidify to become plate which
separate the two daughter cells.
Cleavage cytokinesis
• It occurs in animal cells.
• In this process a cleavage furrow
appears at the middle which
gradually depends and breaks the
parent cell into two daughter cells
28. ANIMAL MITOSIS VS PLANT MITOSIS
Animal mitosis
•Centriole and aster
present.
•Daughter cells separated
by cleavage furrow.
Plant mitosis
•No visible centriole or
ester.
•Daughter cells separated
by cell plate.
29. SIGNIFICANCE OF MITOSIS
• Growth, development healing and repair in multicellular organisms
• Maintains chromosomes number.
• Ensure equal distribution of genetic material.
• Significant role in asexual reproduction of unicellular organisms.
• Healing wounds occur due to mitosis.
• Regeneration involves mitosis.
• Tissue culture and cloning seek help through mitosis.
• Mitosis helps in maintaining the purity of the genome as no
recombination or crossing over takes place.
30. •
Cell division is very important process to continue organisms' life cycle.
• Mitosis is a somatic cell division which causes growth of a living body.
• Pattern of mitosis is fundamentally same in all cells.
• By the process of mitosis not only chromosomes replicate but all
necessary cytoplasm constituents and organelles are divided between
two daughter cells.
• No change in chromosome number.
• Mitosis is observed in all type of cells i.e. haploid, diploid or polyploidy.
• Mitosis usually occurs in vegetative or somatic cells.
• Hereditary material is equally distributed between two daughter cells.
regeneration, healing of wounds and replacement of older cells take
place by mitosis.
CONCLUSION
