In this slide you will get understand about cell division (mitosis).and Interphase, Karyokinesis, cytokinesis

1. By old book
acad

2.  The mitotic division is the process of division of a
somatic cell into two daughter cells, maintaining the
same number of chromosomes as were originally
present in parent cell.
 Its occurs in almost all the cells, except the germ cells.
 During mitosis the nucleus undergoes a number of
complex but regular and well planned steps so that
the process is divided into following phase.

3. 1. Interphase:-
 G1- phase
 S-phase
1. G2-phase
2. Karyokinesis:-
 Prophase
 Metaphase
 Anaphase
 Telophase
3. Cytokinesis:-

4.  Interphase is the interval period between two cell
divisions. it’s the preparatory phase because nucleus
and cytoplasm.
 synthesize and store all the substances which are
essential for cell division .
 Interphase is divided into three sub stage.

5.  The cells grow in size during the period.
 In this phase RNA and protein are synthesized which
are necessary for DNA synthesis.

6.  It is characterized by the replication of DNA and
synthesis of histone protein.

7.  During this period synthesis of RNA and protein
continuous.

8.  It is called nuclear division and is separated into
following phases.
i. Prophase:-
 The nuclear division begins with prophase. the
important events during this phase are as follows-
A. Nuclear changes :-
 the chromatin material condenses into distinct
threads by bsing water.
 The chromatin threads coil like a cylendrical spring
and gradually become shorter and thicker into
chromosomes.

9. Each chromosomes is already doubled due to the
doubling of DNA in interphase.
By the end of prophase each chromosome appear to be
splitted synthesis into two chromateds.
The nucleolus and nuclear memberne disappear by
the end of prophase.
B. Cytoplasmic events:-
 The centroioles divided into two and the daughter
centroiles more towards the opposite poles.
 In the cytoplasm,microtubules begin to orient
between the daughter centrioles and a spindle is
formed. Such a spindle is called amphiaster.

10. ii. Metaphase:-
 The metaphase is marked by the completion of
spindle arrengment of chromosomes on the equator
of spindle.
 Each chromosomes become more compact and
short and its two chromatids separate except at the
centromere which has not divided.
 The chromosomes migrate towards equator of the
spindle. these orient themselves on the equator in
such a fashion that their centromere lie on the
equator and the arms are orinted towards ploes.

11. iii. Anaphase:-
 The centromere of each chromosome divides,
therefore, the sister chromated separate as daughter
chromosomes.
 Daughter chromosomes more apart and are pulled
towards the respective poles of the spindle
chromosomal movement is brought about by the
contraction of spindle fornation.
 The arms of daughter chromosomes are directed
towards equator and centromeres toward the poles
of spindle.

12. iv. Telophase:-
A. Nuclear events:-
 Daughter chromosomes reach poles of the spindle
and form two groups one on either pole of the
spindle.
 Chromosomes uncoil and form chromatin net.
 The nuclear envelope is formed around each group
and nucleolus reappears.
 By the end of telophase two daughter nuclei are
formed.
B. Cytoplasmic event:-
 the spindle fibers disapper.

14. Cytokinesis is the diviion of cell cytoplasm into two separate
cells. its usually occurs in the telophase along with the formation
of the daughter nuclei after the nuclear division. The process of
cytokinesis differs in the plant and animal cells.
 Cytokinesis in animal cell:-
 In animal cell it is started by the appearance of ashallow groove
in the cytoplasm at the equator of spindle.
 Showly and showly it deepens and divide the cytoplasm and cell
into two part.

15. Cytokinesis in plant cell:-
In plant cell it is done by the formation of cell plate at
the equator of dividing cell.
Significance of mitosis:-
The hereditary characters are trasnmitted to daughter
cells.
The duolication of the cells result in the growth of
animal.
The chromosome numbers remain constant and same
in daughter cells as in parent cell.

16. Thank you for
watching