1. Genetic stability - Daughter cells are genetically identical to parent cells.
2. Growth - As multicellular organisms grow, the number of cells making up their tissue increases. The new cells must be identical to the existing ones.
3. Repair of tissues - Damaged cells must be replaced by identical new cells by mitosis.

(i) Some cells exit G₁ and enters a quiescent stage called G₀, where the cell remains metabolically active without proliferation.
(ii) Cells can exist for long periods in G₀ phase. In G₀ cells cease growth with reduced rate of RNA and protein synthesis.
(iii) The G₀ phase is not permanent. Mature neuron and skeletal muscle cell remain permanently in G₀.
(iv) Many cells in animals remains in G₀ unless called on to proliferate by appropriate growth factors or other extracellular signals. G₀ cells are not dormant.

Difference between Mitosis and Meiosis:

S.No	Mitosis	Meiosis
1.	One division	Two divisions
2.	Number of Chromosomes remains the same	Number of Chromosomes is halved
3.	Homologous Chromosomes line up separately on the metaphase plate	Homologous Chromosomes line up in pairs at the metaphase plate
4.	Homologous Chromosome do not pair up	Homologous Chromosome pair up to form bivalent
5.	Chiasmata do not form and crossing over never occurs	Chiasmata form and crossing over occurs
6.	Daughter cells are genetically identical	Daughter cells are genetically different from the parent  cells
7.	Two daughter cells are formed	Four daughter cells are formed

(i) Pachytene:
1. At this stage bivalent Chromosomes are clearly visible as tetrads. Bivalent of meiosis I consists of 4 chromatids and 2 centromeres.
2. Synapsis is completed and recombination nodules appear at a site where crossing over takes place between non-sister chromatids of homologous Chromosome.
3. Recombination of homologous Chromosomes is completed by the end of the stage but the Chromosomes are linked at the sites of crossing over. This is mediated by the enzyme recombinase.
(ii) Diplotene:
1. Synaptonemal complex disassembled and dissolves. The homologous Chromosomes remain attached at one or more points where crossing over has taken place.
2. These points of attachment where 'X' shaped structures occur at the sites of crossing over is called Chiasmata. Chiasmata are chromatin structures at sites where recombination has been taken place.

S.No Cytokinesis in plant cell Cytokinesis in animal cell 1 Cleavage cytokinesis occurs only in lower plants, higher plant cells show cell plate cytokinesis It occurs through cleavage 2 The middle part of spindle persists during cytokinesis. It forms a complex called phragmoplast Spindle degenerates during cytokinesis 3 A mid body is absent A mid body develops centrally 4 A row of vesicles develops in the equatorial plane in plant cell cytokinesis A row of vesicles does not form in animal cell cytokinesis 5 Vesicles fuse to form cell plate Cell plate is not formed 6 There is little role of microfilaments in plant cell cytokinesis Microfilaments actively involved in animal cell cytokinesis 7 It starts with the formation of cell plate during telophase It starts as a constriction in cell membrane during late anaphase or early telophase 8 The cell plate grows from the centre towards the lateral walls, so centrifugal The furrow depends from periphery towards the centre and meets at the centre so centripetal 9 Wall formation occurs in the region of cytokinesis Wall formation is absent