AP BIOLOGY

Detailed explanation-1: -S phase is the period during which DNA replication occurs.

Detailed explanation-2: -The S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is responsible for the synthesis or replication of DNA. In this way, the genetic material of a cell is doubled before it enters mitosis or meiosis, allowing there to be enough DNA to be split into daughter cells.

Detailed explanation-3: -The interphase is the period when the cell is in a non-dividing state and this can be in different stages: the first gap (G1) between the last mitosis and the S phase (phase of DNA synthesis) and the second gap (G2) between the completion of the S phase and the next mitosis (M).

Detailed explanation-4: -The interphase of a normal cell cycle will thus, consist of the G1 (Gap 1) phase, S (Synthesis) phase, and G2 (Gap 2) phase. The S phase is the phase in which replication of DNA will take place which is then followed by histones synthesis. This is the phase taking place between the G1 phase and G2 phase.

Detailed explanation-5: -During interphase the DNA strands are uncoiled (uncondensed) in the nucleus. This uncondensed genetic material is called chromatin; thus an uncondensed chromosome can be called chromatin.