Final answer:
DNA replication occurs during the S phase of the cell cycle and is crucial for both mitotic and meiotic cell divisions. In meiosis I and meiosis II, cells divide without a new round of DNA replication between them, producing genetically unique haploid cells. Mitosis involves one division that results in daughter cells, each with an identical set of chromosomes.
Step-by-step explanation:
Understanding DNA Replication and Cell Division
During the S phase of the cell cycle, DNA replication takes place to ensure that each new cell receives an identical copy of the DNA.
This phase is followed by the G2 phase, where the cell prepares for mitosis or meiosis. In meiosis, unique to germ cells, there are two rounds of cell division: meiosis I and II.
Meiosis I includes stages such as Anaphase I where homologous chromosomes are separated into two haploid cells, and Telophase I which leads directly into meiosis II without a new round of DNA replication.
During meiosis II, specifically in Anaphase II, sister chromatids are pulled apart and cells divide in Telophase II to form four genetically unique haploid cells.
Mitosis, on the other hand, involves only one cell division and is typical for somatic cells. The four phases of mitosis are prophase, metaphase, anaphase, and telophase, followed by cytokinesis.
After Anaphase, the sister chromatids separate and are distributed to each new cell, so that each daughter cell ends up with one copy of each chromosome. This meticulous process ensures that all somatic cells in an organism have the same genetic information.