Home › MCQs › MBBS › Question #10367
Back to Questions
MBBS QUESTION #10367
Question 1
DNA polymerase synthesizes new DNA strands only in which direction, a constraint that necessitates discontinuous synthesis (via Okazaki fragments) on the lagging strand during replication?
  • 5' to 3'✔️
  • 3' to 5'
  • Bidirectionally, starting from any point along the template
  • Direction is irrelevant to DNA polymerase's mechanism
Correct Answer Explanation
DNA polymerases can only add new nucleotides to the free 3'-hydroxyl end of a growing strand, synthesizing DNA exclusively in the 5' to 3' direction; since the two template strands run antiparallel, one new strand (leading) can be synthesized continuously while the other (lagging) must be synthesized discontinuously as short Okazaki fragments, later joined by DNA ligase.