During the eukaryotic cell cycle, DNA is replicated in which phase?

• A. S phase of interphase
• B. G$2$ phase of interphase
• C. G$1$ phase of interphase
• D. M phase (mitosis)

Answer: (A)

Verified step by step guidance

1. Understand the phases of the eukaryotic cell cycle, which include G1 phase, S phase, G2 phase (all part of interphase), and M phase (mitosis).
2. Recall that the G1 phase is primarily focused on cell growth and preparation for DNA replication, but DNA itself is not replicated here.
3. Identify that the S phase (Synthesis phase) is the specific phase during which DNA replication occurs, meaning the cell duplicates its entire genome.
4. Note that the G2 phase follows DNA replication and involves further growth and preparation for mitosis, but no DNA replication happens here.
5. Recognize that the M phase is when mitosis occurs, involving the division of the replicated chromosomes into two daughter cells, not DNA replication.