Question 1
Multiple choiceMedium1 markAt a replication fork moving to the right, the upper parental template runs 3′→5′ from left to right, and the lower template runs 5′→3′. Which description of new-strand synthesis is correct?
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Answer: D. DNA polymerase extends a new strand at its 3′ end, so synthesis proceeds 5′→3′. The upper template allows continuous synthesis toward the fork from one primer. The lower template is copied away from the fork in Okazaki fragments, requiring repeated primers. A: reverses which template supports leading-strand synthesis toward the fork. B: reverses the direction of DNA synthesis; new DNA is made 5′→3′. C: reverses primer frequency: continuous synthesis uses one primer, whereas discontinuous synthesis requires repeated primers. Remember: the lagging strand is made discontinuously as Okazaki fragments.