Question

Which of the following is incorrect with respect to meiosis?

• A. It involves two cycles of DNA replication, one before meiosis-I and another before meiosis-II
• B. It involves crossing over that leads to recombination
• C. Sister chromatids separate during anaphase-II
• D. Nuclear membrane disappears during prophase

Answer 1

The correct option is A It involves two cycles of DNA replication, one before meiosis-I and another before meiosis-II

Meiosis is a type of reductional division in which the parent cell divides to form four daughter cells. Meiosis involves two sequential cycles of nuclear and cell divisions called as meiosis-I and meiosis-II.

Before the cell starts to divide (either by mitosis or meiosis), it undergoes a preparatory phase called interphase. Interphase includes G${}_1$, S and G${}_2$ phases. Cell undergoes DNA replication in the S phase of interphase. Due to DNA replication, the total content of DNA doubles in the cell. So, the DNA replicates before meiosis-I in interphase and no further DNA replication takes place later.

Crossing over is a significant event occuring during meiosis which is responsible for recombination.

The homologous chromosomes separate during anaphase-I and sister chromatids separate during meiosis-II.

Nuclear membrane disappears during prophase.