In: Biology
Chromatid :- Chromatid is one of two identical halves of replicated chromosome.
Sister chromatid :- Jointed chromatids of a chromosome is known as sister chromatid.
Centromere :- it links the pair of sister chromatid have specialised DNA sequence.
centrosome :- is an organelle contain two centrioles which help in cell division only present in animal cell .
centriole :- cylindrical organelle consist of tubulin protein.
mitotic spindle:- centriole give rise to spindle fibres they help in cell division.
Metaphase :- in this phase centrosomes divided into two centrioles .centrioles move towards the poles of a cell give rise to spindle fibres .Spindle fibre is attached to the centromere of a chromosome .All chromosomes are arranged at metaphasic plate.
G2 phase :- Protein synthesis , ATP synthesis ,cell growth
G1 phase :- Protein synthesis ,ATP synthesis , cell growth , synthesis of various enzyme and nutrients
S phase :- DNA replication occur but,number of chromosomes remain same
In metaphase all chromosomes are lined in metaphasic plate with the help of spindle fibres .In late metaphase chromosomes are divided into chromatid and each chromatid will carry a centromere with the help of centromere spindle fibres are attached to the chromosome.Spindle fibres stretch and chromatid move towards the poles.
Purpose of mitosis:- parent cell divided into two equal daughter cells .So,genetic material of parent cell and daughter cells remain same,daughter cells are resembles to each other .Daughter cells are similar to parent cell.
cytokinesis :- the process of cytoplasmic division.
In plant cell cytokinesis occur by cell plate method.
In animal cell cytokinesis occur by cell clevage method.