Okazaki fragments are produced on which strand?

Okazaki fragments are produced on which strand?

• A. Lagging strand
• B. Leading strand
• C. Template strand
• D. Coding strand

Answer: (A)

DNA polymerase can only add nucleotides in the 5' to 3' direction. Because the two DNA strands run antiparallel, the strand oriented 3' to 5' toward the fork must be copied in short bursts as the fork opens. These short, newly made pieces are called Okazaki fragments. The other strand runs 5' to 3' toward the fork, so it can be synthesized continuously as the fork advances. Primase lays down RNA primers for each fragment, and later DNA ligase joins the fragments into a continuous strand. So Okazaki fragments form on the lagging strand, not the leading strand, and the terms template or coding strand are more relevant to transcription than to this replication concept.

DNA polymerase can only add nucleotides in the 5' to 3' direction. Because the two DNA strands run antiparallel, the strand oriented 3' to 5' toward the fork must be copied in short bursts as the fork opens. These short, newly made pieces are called Okazaki fragments. The other strand runs 5' to 3' toward the fork, so it can be synthesized continuously as the fork advances. Primase lays down RNA primers for each fragment, and later DNA ligase joins the fragments into a continuous strand. So Okazaki fragments form on the lagging strand, not the leading strand, and the terms template or coding strand are more relevant to transcription than to this replication concept.