AP BIOLOGY

Detailed explanation-1: -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).

Detailed explanation-2: -S phase (Synthesis Phase) is the phase of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Since accurate duplication of the genome is critical to successful cell division, the processes that occur during S-phase are tightly regulated and widely conserved.

Detailed explanation-3: -S phase. In S phase, the cell synthesizes a complete copy of the DNA in its nucleus. It also duplicates a microtubule-organizing structure called the centrosome.

Detailed explanation-4: -Chromosome duplication occurs during S phase of the cell cycle, whereas most other cell components are duplicated continuously throughout the cycle. During M phase, the replicated chromosomes are segregated into individual nuclei (mitosis), and the cell then splits in two (cytokinesis).

Detailed explanation-5: -During S phase, which follows G1 phase, all of the chromosomes are replicated. Following replication, each chromosome now consists of two sister chromatids (see figure below). Thus, the amount of DNA in the cell has effectively doubled, even though the ploidy, or chromosome count, of the cell remains at 2n.