Question

What is mitosis ? and miosis ?
what are its features ? why does it Neccessary for the Growth of the organism ?

No copy Pasting should be here

Answer 1

Hola..!

Mitosis and meiosis are nothing but cell cycles ..let us see them in detail.

Mitosis-in this type of cell cycle, the cell undergoes division and produce 2 daughter cells which are identical to parent cell.
there will be no change in the ploidy
a diploid cell will produce 2 diploid cells through mitosis.

Mitosis is Divided in to following stages:
G1 phase
S phase
G2 phase
M phase

M phase is again divided in to
prophase
metaphase
anaphase
telophase

Common examples of mitosis:
Single celled zygote divides and gives rise to multicellular embryo by mitotic divisions..
-Wound healing,tissue repairing is also possible only due to mitosis.

Meiosis-in this type of cell cycle,the cell undergoes division and produces 4 daughter cells.It is the meiosis responsible for variations.This happens due to recombinations.
There will be change in the ploidy..
a diploid cell will produce 4 haploid cells through meiosis.

Meiosis consists of two divisions..
Meiosis 1
Meiosis 2

Meiosis 1 can be divided in to
G1
S
G2
M phase 1

G1 ,G2 ,S phases are collectively known as interphase.

M phase 1 is divided into
Prophase1
Metaphase1
Anaphase1
Telophase 1


prophase 1 is again divided into..
Leptotene
Zygotene
Pachytene(crossing over takes place)
Diplonema
Diakinesis

M phase 2 is divided in to
Prophase 2
Metaphase 2
anaphase 2
telophase 2

Meiosis helps in formation of gametes(in diploid organisms only..beacuse in haploid organisms gametes formation takes place by mitosis)

HOPE THIS HELPS YOU.

Answer 2

Hi friend here is your answer

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MITOSIS
It is defined as the process in which a single parent cell divides and forms two daughter cells each containing the same number and kind of Chromosomes as that of the parent cell

Mitosis and its detailed study was given by A. Scheiden The term was coined by Walther Fleming (1878) a German biologist In mitosis the daughter cells receive an identical copy of parental genome. It takes place in the somatic cells. It represents a brief period of cell cycle and occurs between G2 and G1 phases

Types of Mitosis

1)Astral
2)Anastral

Mitosis in which the spindle fibers have centrioles and asters is called as Centric or Astral mitosis

Mitosis in which the centrioles and asters are absent is called Acentric or Anastral mitosis It is seen in higher plants

Stages

1) Karyokinesis (Nuclear Division)
It is an uninterrupted and continuous process it is divided into further four stages

1) Prophase
2)Metaphase
3)Anaphase
4)Telophase

(For the detailed information of this phases refers to the attachments)

2) Cytokinesis (Cytoplamic division)

Significance of Mitosis

1) Mitosis produces cells with identical genome

2)It brings about growth of tissues and the organism as whole

3) It brings about increase in no of cells

4)Replace worn out and damaged cells

5) maintains nucleocytoplasmic ratio of the cells

6) In unicellular organisms like bacteria and yeast it brings about asexual reproduction

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Hope it helps you...............!!
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