Question

In which stage of the cell cycle does DNA replication occur?

Answer 1

During the synthesis phase of interphase.

Explanation:

There are two broad sections of the cell cycle, interpase and mitosis.

Interphase is divided into `G_1, S and G_2`.
Mitosis is divided into prophase, metaphase, anaphase, and telophase.

`G_1`: "gap one". cell growth.
S: "synthesis". DNA replication
`G_2`: "gap two". the cell prepares for mitosis, organelles duplicate.

P: prophase. nucleus membrane breaks down.
M: metaphase. chromosomes line up in the middle of the cell.
A: anaphase. chromosomes are separated into two identical chromatids and pulled towards opposite poles of the cell.
T: telophase. the chromatids rewind tightly. nucleus reforms.

Then there is cytokinesis, the physical splitting of the cell.