Which of the following processes occurs in both mitosis and meiosis?

• A. Reduction of chromosome number
• B. Crossing over
• C. DNA replication
• D. Synapsis of homologous chromosomes

Answer: (C)

Verified step by step guidance

1. Begin by understanding the key processes involved in both mitosis and meiosis. Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth. Meiosis, on the other hand, is a type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell, which is essential for sexual reproduction.
2. Identify the process that is common to both mitosis and meiosis. DNA replication is a fundamental process that occurs before both mitosis and meiosis. It ensures that each daughter cell receives a complete set of chromosomes.
3. Understand that DNA replication occurs during the S phase of the cell cycle, prior to the actual division processes of mitosis and meiosis. This replication is crucial for maintaining genetic consistency in mitosis and for providing the necessary genetic material for the reduction division in meiosis.
4. Recognize that the other processes listed, such as reduction of chromosome number, crossing over, and synapsis of homologous chromosomes, are specific to meiosis. Reduction of chromosome number and crossing over are key features of meiosis that contribute to genetic diversity.
5. Conclude that DNA replication is the process that occurs in both mitosis and meiosis, as it is essential for the preparation of cell division in both types of processes.