Which sequence correctly lists the phases contained within interphase in proper order?

Which sequence correctly lists the phases contained within interphase in proper order?

• A. S, G1, G2
• B. G1, S, G2
• C. G2, G1, S
• D. G1, G2, S

Answer: (B)

Interphase is the period of the cell cycle when the cell grows and duplicates its contents in preparation for division. It unfolds in three consecutive stages: first, G1, a growth and metabolic activity phase where the cell increases in size and makes the RNA and proteins needed for DNA replication. Next comes S phase, the DNA synthesis stage where the cell copies its genetic material so that each daughter cell will have a full set of chromosomes. Finally, G2 is a second growth and preparation phase, during which the cell produces what’s needed for mitosis and checks for any DNA damage before division. Because DNA replication must occur before the cell enters mitosis, the proper order is G1, then S, then G2. Any sequence that places S before the initial growth phase or places G2 before completion of DNA replication would not align with how the cell readies itself for division.

Interphase is the period of the cell cycle when the cell grows and duplicates its contents in preparation for division. It unfolds in three consecutive stages: first, G1, a growth and metabolic activity phase where the cell increases in size and makes the RNA and proteins needed for DNA replication. Next comes S phase, the DNA synthesis stage where the cell copies its genetic material so that each daughter cell will have a full set of chromosomes. Finally, G2 is a second growth and preparation phase, during which the cell produces what’s needed for mitosis and checks for any DNA damage before division.

Because DNA replication must occur before the cell enters mitosis, the proper order is G1, then S, then G2. Any sequence that places S before the initial growth phase or places G2 before completion of DNA replication would not align with how the cell readies itself for division.