OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What process involves two divisions to produce gametes?

1. Mitosis

2. Meiosis

3. Fertilization

4. Binary Fission

The correct answer is: Meiosis

The process that involves two divisions to produce gametes is meiosis. This specialized form of cell division reduces the chromosome number by half, resulting in four non-identical haploid gametes from a single diploid cell. Meiosis consists of two main stages: meiosis I and meiosis II. During meiosis I, homologous chromosomes are separated, which reduces the chromosome number. This is followed by meiosis II, where sister chromatids are separated. The outcome of meiosis is critical for sexual reproduction, as it ensures genetic diversity through processes such as crossing over and independent assortment. This genetic variation is important for evolution and adaptability in populations. Mitosis, in contrast, involves a single division and is responsible for growth and repair by producing two identical diploid cells. Fertilization refers to the fusion of gametes to form a zygote, not the process that generates gametes themselves. Binary fission is a method of asexual reproduction seen in prokaryotic organisms where one cell divides into two identical daughter cells, again not involving two divisions like meiosis does.