- A DNA polymerase is only active during S-phase due to availability of dNTPs and coordinated licensing of replication origins
- B DNA molecules are understood to be physically incapable of being replicated anywhere outside the cell nucleus during normal conditions
- C Histone proteins are understood to be largely absent from chromatin during every other phase of the cycle as generally observed
- D RNA polymerase is understood to actively block DNA polymerase activity during all other phases of the cell cycle in typical laboratory settings
Correct answer: A. DNA polymerase is only active during S-phase due to availability of dNTPs and coordinated licensing of replication origins
Explanation: Replication is tightly regulated and licensed to occur only once per cell cycle, during S-phase, coordinated with the availability of replication machinery and resources, alongside duplication of other organelles like centrioles.
Concept context
DNA structure, replication, transcription, translation, the genetic code, and gene regulation (lac operon). The single most important chapter for NEET molecular biology.