In replication of a linear double-stranded DNA molecule, one end of each strand becomes shorter in each round of replication. This happens because:
A)each replicated DNA strand requires an RNA primer.
B)the RNA primer cannot be replaced at the very end of a DNA strand.
C)DNA polymerase elongates a growing DNA strand at only the 3' end.
D)All of these choices are correct.

Question

Quizplus · Accepted Answer

All of these choices are correct and collectively explain why linear DNA molecules become shorter with each round of replication. DNA polymerase requires an RNA primer to initiate replication and can only add nucleotides to the 3' end of a growing DNA strand. At the ends of linear chromosomes, the RNA primer is removed, and there is no upstream 3' end for DNA polymerase to extend, leading to progressively shorter DNA molecules with each replication cycle.

In Replication of a Linear Double-Stranded DNA Molecule, One End