🏥 USMLE Exam Prep

During DNA replication, which enzyme is responsible for joining the Okazaki fragments on the lagging strand?

A DNA polymerase I
B DNA helicase
C DNA primase
D DNA ligase

✓ Correct Answer: Option D

DNA ligase catalyzes the formation of phosphodiester bonds between adjacent nucleotides, sealing the nicks between Okazaki fragments that are synthesized discontinuously on the lagging strand during DNA replication.

💡 Why is D) the correct answer?

The correct answer to the question "During DNA replication, which enzyme is responsible for joining the Okazaki fragments on the lagging strand?" is Option D: DNA ligase.

The other options — A) DNA polymerase I, B) DNA helicase, C) DNA primase — are incorrect for this USMLE Exam Prep question. As explained above: DNA ligase catalyzes the formation of phosphodiester bonds between adjacent nucleotides, sealing the nicks between Okazaki fragments that are synthesized discontinuously on the lagging strand during …

📚 About This USMLE Exam Prep Practice Question

This 1-level USMLE Exam Prep question from the Step 1 – Basic Sciences topic is part of BrainForge Quiz's free exam preparation library. Each question includes the correct answer and a detailed explanation to help you understand the underlying concept, not just memorize the answer.

How to use this page: Read the question above, consider all four options (A through D), then check the highlighted correct answer and explanation. For active timed practice, start a free USMLE Exam Prep practice test or use flashcards for spaced repetition review.

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