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It is reductional division, which takes place in the reproductive cell. It is a longer process in comparison to mitosis. It completes in the following steps:
It is further divided into:
The two daughter cells that are produced at the end of telophase I undergo meiosis II. The process of meiosis II includes:
The process in which a diploid cell divides to form four haploid cells that are never identical is called meiosis cell division.
The sub-phases of prophase I of meiotic cell division are:
The five important features of prophase I are:
The following incidents occur during this stage.
The two incidents during metaphase I are:
i. Due to contraction of spindle fibers, homologous chromosomes separate.
ii. The homologous move towards opposite poles.
The two incidents during telophase II are:
i. Chromosomes form groups at opposite poles.
ii. Nuclear membrane reappears around each set of chromosomes.
The significances of meiotic cell division are:
i. It helps to maintain the definite number of chromosomes for each species.
ii. It helps in bringing variation among individual due to crossing over.
iii. It is responsible for the transmission of characteristics from parents to offspring.
Synapsis is the process by which paternal and maternal chromosomes come together to form a homologous pair. It occurs during Zygotene of phrases I of meiosis.
During Zygotene of prophase I, chromosomes from homologous pair, i.e. one chromosome from father and one from mother come together to form a pair by synapsis.
Any organisms results due to the fusion of male and female gametes during sexual reproduction. During fertilization the chromosomes of male and female gametes are added up in the offspring. In order to maintain the number of chromosomes from generation to generation in a species it is necessary for gametes to have half the number of chromosomes. If the gametes had the same number of chromosomes as the mother cell, then during sexual reproduction, the number of chromosomes would double in each generation.