During which stage of the cell cycle is the cell content duplicated in preparation for cell division?

• A. S phase
• B. G1 phase
• C. M phase
• D. G2 phase

Answer: (A)

DNA replication happens during the synthesis phase of the cell cycle. This is when the cell doubles its DNA content so that, as division proceeds, each new cell inherits a complete set of genetic information. During this phase, each chromosome is copied to form two sister chromatids held together at the centromere, ready for separation in mitosis.

Other stages focus on growth or preparation rather than copying DNA: growth and nutrient uptake occur in the first gap phase, final preparation for division happens in the second gap phase, and the actual division occurs during mitosis and cytokinesis.