Sexual reproduction is associated with _.
A. mitosis
B. meiosis
C. binary fission
The Correct Answer and Explanation is:
The correct answer is B. meiosis.
Explanation:
Sexual reproduction involves the fusion of two distinct gametes (reproductive cells) from two different individuals—one from each parent. In humans and most other eukaryotic organisms, these gametes are the sperm (from the male) and the egg (from the female). For sexual reproduction to occur, each gamete must have half the number of chromosomes that are typical for the organism. This reduction in chromosome number is achieved through meiosis, a type of cell division distinct from mitosis.
Meiosis has two key stages: meiosis I and meiosis II. In meiosis I, homologous chromosomes (one from each parent) are separated into two different cells, ensuring that each gamete gets only one copy of each chromosome. In meiosis II, similar to mitosis, the sister chromatids of each chromosome are separated. As a result, four non-identical daughter cells are produced, each with half the chromosome number (haploid) of the original cell (diploid). This halving of chromosomes is crucial for maintaining the stability of an organism’s chromosome number across generations.
In sexual reproduction, when the sperm and egg fuse during fertilization, they form a zygote with a full set of chromosomes (diploid). This zygote will then undergo mitosis to produce all the cells of the new organism, but the initial step of reducing chromosome number through meiosis ensures genetic diversity and proper chromosome number across generations.
Mitosis, in contrast, is the type of cell division involved in asexual reproduction or the growth and repair of tissues in multicellular organisms. It produces two genetically identical daughter cells, maintaining the same chromosome number as the parent cell. Binary fission, often seen in prokaryotes like bacteria, is a form of asexual reproduction that also involves the division of a single cell into two identical cells.
Thus, sexual reproduction specifically relies on meiosis for the creation of gametes with half the chromosome number, allowing for genetic diversity and proper reproduction.