what is the S phase?

Question

We say that DNA replicates in the S phase. What does that entail?

Answer 1

The S phase is the synthesis stage of interphase.
Interphase consists of G1, S, and G2.

DNA replicates during S. That means that DNA is copied during the S phase, so there is twice as much DNA in the nucleus. During prophase of mitosis when the chromatin condenses to make chromosomes, the chromosomes that form are double-stranded. Each strand or a sister chromatid is one of the copies of DNA from the S phase.