AP BIOLOGY

Detailed explanation-1: -Final answer: The duplication of chromosomes or DNA occurs during Interphase. Q. Two key events take place, during S-phase in animal cells, DNA replication and duplication of centriole.

Detailed explanation-2: -Then, at a critical point during interphase (called the S phase), the cell duplicates its chromosomes and ensures its systems are ready for cell division. If all conditions are ideal, the cell is now ready to move into the first phase of mitosis.

Detailed explanation-3: -DNA replicates in the S phase of the cell cycle and initiates at specific regions in the DNA sequence known as DNA replication ‘origins’.

Detailed explanation-4: -The cell cycle has two major phases: interphase and the mitotic phase (Figure 6.3). During interphase, the cell grows and DNA is replicated.

Detailed explanation-5: -In the eukaryotic cell cycle, chromosome duplication occurs during “S phase” (the phase of DNA synthesis) and chromosome segregation occurs during “M phase” (the mitosis phase).