AP BIOLOGY

Detailed explanation-1: -DNA replicates in the S phase of the cell cycle and initiates at specific regions in the DNA sequence known as DNA replication ‘origins’. A number of proteins participate in DNA replication and the process is subject to scrutiny by cell surveillance mechanisms called cell cycle checkpoints.

Detailed explanation-2: -Also known as gap 1 phase, it is the first phase of the cell cycle in cell division. The cell is metabolically active and continuously grows in this phase of the cell cycle. However, no DNA replication takes place in this phase.

Detailed explanation-3: -DNA Synthesis During S phase, an enzyme called helicase unwinds the DNA strand, in the same way that you would unzip a zipper. The two single DNA strands can then be used as templates to form two identical double DNA strands.