How do mitosis and meiosis differ?
A. Mitosis results in two diploid daughter cells, whereas meiosis results in four haploid daughter cells.
B.Mitosis involves one DNA replication, whereas meiosis has two DNA replication events.
C. Mitosis results in gametes, such as egg and sperm, whereas meiosis occurs in somatic cells, such as hair, muscle, and organ cells.
D. Mitosis only occurs during an organism’s period of growth and development, whereas meiosis occurs throughout life.
The Correct Answer and Explanation is :
The correct answer is A. Mitosis results in two diploid daughter cells, whereas meiosis results in four haploid daughter cells.
Explanation:
Mitosis and meiosis are two different processes of cell division, but they serve distinct purposes in an organism.
- Mitosis: This process occurs in somatic (body) cells and is primarily responsible for growth, development, tissue repair, and asexual reproduction. In mitosis, a single diploid cell (containing two sets of chromosomes, one from each parent) undergoes division to produce two genetically identical diploid daughter cells. Each daughter cell has the same number of chromosomes as the parent cell (2n). Mitosis involves only one round of DNA replication followed by a series of stages: prophase, metaphase, anaphase, and telophase, leading to two identical cells.
- Meiosis: Meiosis, on the other hand, occurs in germ cells (such as egg and sperm cells) and is essential for sexual reproduction. It reduces the chromosome number by half to produce four haploid daughter cells (each with half the number of chromosomes as the parent cell). These haploid cells are genetically distinct from one another due to processes like crossing-over and independent assortment. Meiosis involves two rounds of division: meiosis I and meiosis II, each with its own phases (prophase, metaphase, anaphase, and telophase), and two rounds of DNA replication. This reduction in chromosome number ensures that when two gametes (egg and sperm) combine during fertilization, the resulting zygote has the correct diploid number of chromosomes.
Why the other options are incorrect:
- B: Meiosis has two rounds of division but involves only one round of DNA replication (not two rounds of DNA replication per division). This contrasts with mitosis, where there is also only one round of DNA replication.
- C: Mitosis occurs in somatic cells, while meiosis occurs in germ cells (egg and sperm), not the other way around.
- D: Mitosis occurs throughout an organism’s life for growth and repair, while meiosis occurs only during sexual reproduction, not throughout life.