Q.Where and why do mitosis and meiosis occur? Also write their importance. OR Write a brief description, with the help of diagrams, of any four different stages of the prophase of meiosis-I.

Interkinesis is the short interval, without DNA replication, that separates the two meiotic divisions.

Meiosis involves two successive divisions: Meiosis I (reductional division, halving chromosome number) followed by Meiosis II (equational division, similar to mitosis). Between the end of telophase I and the start of prophase II, cells pass through a brief phase called interkinesis, which is usually short-lived and, critically, does NOT involve replication of DNA (since the chromosome number is already reduced and each chromosome already has two sister chromatids from the pre-meiotic S-phase).

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Meiocytes are diploid cells specialised to undergo meiosis, halving the chromosome number to produce haploid products.

In a sexually reproducing organism, not all cells divide by meiosis — only certain designated diploid cells, called meiocytes, are competent to undergo meiosis. During meiosis, a single meiocyte undergoes one round of DNA replication followed by two successive nuclear divisions (meiosis I and meiosis II), producing four haploid (n) daughter cells. In animals, meiocytes give rise to gametes (sperm/egg); in flowering plants, they give rise to spores — for example, pollen mother c …

Meiosis produces four haploid daughter cells from one diploid parent cell.

Only meiosis reduces the chromosome number to half; mitosis maintains it.

Mitosis is an equational division: one diploid (2n) parent cell produces two diploid (2n) daughter cells with the SAME chromosome number as the parent -- used for growth and repair. Meiosis, in contrast, is a reductional division involving two successive divisions (meiosis I and meiosis II) but only ONE round of DNA replication: a diploid (2n) parent cell ultimately produces four haploid (n) daughter cells, each with HALF the chromosome number of the parent. This halving happens specifically at anaphase I, …

Meiosis is the type of division that occurs in germ cells to produce gametes.

Somatic (body) cells divide by mitosis, producing two genetically identical diploid daughter cells for growth and repair. Germ cells (in the gonads — testes and ovaries), however, undergo meiosis, a special two-step division (meiosis I and meiosis II) that reduces the chromosome number by half, from diploid (2n) to haploid (n), and also introduces genetic variation through crossing ov …

Zygote is diploid (2n); endosperm is triploid → (c).

• The zygote forms by fusion of two haploid gametes → it is diploid (2n).
• In angiosperms the endosperm results from triple fusion (2 polar nuclei + 1 sperm) → triploid (3n), not diploid. …