Question

Meiosis gives rise to :

• A. Four haploid cells
• B. Two haploid cells
• C. Two diploid cells
• D. Three haploid cells

Hint:

- Mitosis: One division $\rightarrow$ Two identical diploid ($2n$) cells.
- Meiosis: Two divisions $\rightarrow$ Four unique haploid ($n$) cells.
- The reduction in ploidy from diploid to haploid is necessary to maintain a constant chromosome number across generations upon fertilization.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Meiosis is a specialized form of cell division that reduces the chromosome number in the daughter cells by half compared to the parent cell.
It is crucial for sexual reproduction, leading to the formation of gametes (pollen grains and egg cells in plants, sperm and egg cells in animals).

Step 2: Detailed Explanation:
The process of meiosis involves one round of DNA replication followed by two successive nuclear divisions:
1. Meiosis I (Reductional Division):
- Homologous chromosomes pair up during Prophase I (where crossing over and genetic recombination occur).
- In Anaphase I, homologous chromosomes separate and move to opposite poles.
- This division results in two haploid cells, each containing half the number of chromosomes, though each chromosome still consists of two sister chromatids.
2. Meiosis II (Equational Division):
- This division resembles mitosis.
- Sister chromatids of each chromosome separate during Anaphase II and move to opposite poles.
- Each of the two cells from Meiosis I divides, resulting in a total of four haploid daughter cells containing single-chromatid chromosomes.
This process ensures genetic diversity through crossing over and independent assortment of maternal and paternal chromosomes.

Step 3: Final Answer:
Thus, meiosis results in the formation of four haploid cells.