Question

Which of the following statements is/are correct?
(A) Meiosis involves two sequential cycles of each event, i.e., DNA replication and nuclear division.
(B) Meiosis involves pairing of homologous chromosomes and recombination between them.
(C) Four haploid cells are formed at the end of meiosis-I.
(D) Meiosis ensures the production of haploid phase in the life cycle of sexually reproducing organisms.

• A. (B) and (D)
• B. (A), (B) and (D)
• C. (B), (C) and (D)
• D. (C) and (D)

Answer 1

The correct option is A (B) and (D)

Meiosis is a type of cell division in which the daughter cells produced carry half the number of chromosomes as compared to the parental cells. Hence, it is also called reductional division.

Meiosis occurs in two phases: meiosis I and meiosis II. The DNA replication occurs once in interphase before meiosis I. After completion of interphase events, the cell proceeds to meiosis I. In the prophase stage of meiosis I occurs the pairing of homologous chromosomes, also called synapsis. This favors crossing over or the exchange of fragments of non-sister chromatids of homologous chromosomes, that leads to recombination.

After prophase, the cell progresses to metaphase, anaphase and telophase of meiosis I. The resultant cells enter prophase of meiosis II. Though there is a short span between meiosis I and meiosis II called interkinesis, however, DNA replication does not take place.
Meiosis ensures the production of haploid phase in the life cycle of sexually reproducing organisms whereas fertilisation restores the diploid phase. For example, meiosis occurs during gametogenesis in plants and animals which leads to the formation of haploid gametes.