Question

Explain the process of meiosis 1?

Answer 1

Hint:Meiosis is the type of cellular division that takes place in the sex cells to produce gametes. Before meiosis 1 the cell undergoes Growth and synthesis phase where the proteins and the genetic material replicates before undergoing division.

Complete answer:
Meiosis takes place in two phases- meiosis I and meiosis II.
Meiosis I- It is the reduction division which involves the separation of homologous chromosomes.

The phases of Meiosis I are
i) ProphaseI- It is the longest phase of meiosis I which is very important as it involves intermixing of genetic material. In this phase, pairing of homologous chromosomes takes places. The exchange of segments between the sister chromatids takes place which is called crossing over.
The prophase has been divided into four stages:
a) leptotene
b) pachytene
c) zygotene
d) diplotene
e) diakinesis.
The spindle fibres start developing.
ii) MetaphaseI- In this phase the homologous chromatids arrange themselves at the equator.
iii) AnaphaseI- The homologous chromosomes are pulled apart towards the opposite poles.
iv) TelophaseI- In the telophase, the chromosomes completely move towards the pole and the constriction at the equator takes place dividing the nucleus into two. The spindle fibres disappear
v) Cytokinesis- In this stage the cell wall forms in the plant cells. This results in the formation of two daughter cells.

Note: Meiosis I results in two daughter cells. The two cells have the homologous pair with the segment of paternal chromosome and maternal chromosome which is resulted by crossing over. The main purpose of meiosis I is intermixing of genetic material and reducing the number of chromosomes from 46 to 23.