Meiosis accomplishes all of the following EXCEPT
Multiple Choice
growth and repair.
reduction of chromosome number (from 2?? ?to ?? ).
gamete production.
providing genetic variation in sexually reproducing organisms.
The Correct Answer and Explanation is:
The correct answer is: growth and repair.
Explanation:
Meiosis is a specialized type of cell division that occurs in sexually reproducing organisms. It serves several important functions, but growth and repair is not one of them. Here’s why:
- Growth and Repair
Growth and repair of tissues in multicellular organisms primarily rely on mitosis, not meiosis. Mitosis produces genetically identical daughter cells that help the body grow, replace dead or damaged cells, and maintain tissue health. Meiosis, by contrast, occurs only in germ cells (cells in the reproductive organs) and produces gametes (sperm and eggs), not cells used for bodily growth or tissue repair. - Reduction of Chromosome Number
Meiosis reduces the chromosome number by half, going from diploid (2n) to haploid (n). In humans, for example, diploid cells have 46 chromosomes, while haploid gametes have 23 chromosomes. This reduction is crucial because when gametes fuse during fertilization, the resulting zygote restores the diploid chromosome number, maintaining genetic stability across generations. - Gamete Production
The primary function of meiosis is to produce gametes. Through two rounds of division (meiosis I and meiosis II), a single diploid germ cell produces four haploid gametes. These gametes are essential for sexual reproduction. - Providing Genetic Variation
Meiosis introduces genetic variation through two main mechanisms:- Crossing over: Homologous chromosomes exchange genetic material during prophase I, creating new combinations of alleles.
- Independent Assortment: During metaphase I, homologous chromosome pairs align randomly, leading to diverse combinations of maternal and paternal chromosomes in gametes.
This genetic variation is vital for evolution and adaptation in sexually reproducing populations.
Summary:
- Meiosis does not contribute to growth and repair. That is the role of mitosis.
- Meiosis reduces chromosome number, produces gametes, and increases genetic diversity.
Understanding the distinction between mitosis and meiosis is fundamental in biology, especially when studying reproduction and genetics.