What is a characteristic feature of the S Phase in the cell cycle?

A defining characteristic of the S Phase, or synthesis phase, in the cell cycle is that it is when DNA replication occurs. During this phase, the cell's genetic material is duplicated in preparation for cell division. The semiconservative model of DNA synthesis explains how each new double helix is made up of one old strand and one newly synthesized strand, ensuring that genetic information is accurately passed on to daughter cells. This accurate duplication is crucial for maintaining genetic fidelity during cell division.

In the context of other options, while cell growth and metabolic processes do occur in other phases, such as Growth Phase 1 (G1), they are not exclusive or definitive for the S Phase. Preparation for division, which is more characteristic of the G2 phase, focuses on further preparations following DNA synthesis. Lastly, the duration of mitosis, which is when the actual cell division takes place, is unrelated to the S Phase, reinforcing the uniqueness of the DNA synthesis process that occurs during this specific phase.