Question

In which phase of the cell cycle does replication of DNA take place?

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

Answer 1

The Correct Option is C

The cell cycle is divided into several key phases, which are important for cell growth and division. These phases include: 

• G1 Phase: Cell growth occurs, and the cell performs its normal functions. It is a preparatory phase preceding DNA replication.
• S Phase: DNA replication takes place in this phase. Each chromosome is duplicated to ensure that both daughter cells obtain an identical set of chromosomes.
• G2 Phase: The cell continues to grow and prepares for cell division. This phase follows DNA replication and precedes mitosis.
• M Phase: This is the mitosis phase, where cell division occurs, resulting in two daughter cells.

Therefore, the correct answer to the question "In which phase of the cell cycle does replication of DNA take place?" is: S phase.

Answer 2

DNA replication occurs during the S phase (Synthesis phase) of the cell cycle. This phase is responsible for the synthesis of DNA, where the entire genome is replicated to ensure that each daughter cell receives a complete set of genetic material.

• G1 phase: The cell grows and carries out normal metabolic functions but does not replicate its DNA.
• M phase: This is the mitotic phase, where the cell undergoes mitosis and divides into two daughter cells, but DNA replication does not occur here.
• S phase: This is where DNA replication occurs. Each chromosome is duplicated, forming two sister chromatids.