Q. DNA synthesis in eukaryotes occurs during which phase of the mitotic cell cycle?
(A) M
(B) G1
(C) S
(D) G0
Ans: S
Solution:
(C) S
DNA synthesis in eukaryotes occurs during the S phase of the mitotic cell cycle. The cell cycle consists of several phases, including G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis). During the S phase, the cell undergoes DNA replication, where each chromosome’s DNA is duplicated to form sister chromatids. After DNA synthesis is completed in the S phase, the cell proceeds to the G2 phase, where it prepares for mitosis during the M phase. Following mitosis, the cell can either enter another round of the cell cycle or go into a non-dividing state known as G0.