Question

During DNA replication, why is replication of the lagging DNA strand a problem compared to the leading DNA strand, and how is this problem overcome?

Answer 1

Unlike the bacterial chromosomes, the chromosomes of the eukaryotes are linear that is rod-shaped, which means that they have ends. These ends can pose a problem for DNA replication. The DNA which is at the very end of the chromosome will not be fully copied in each round of replication, which will result in a slow, gradual shortening of the chromosome.

Telomerase solves the "end replication problem."

Leading and lagging strands which are produced during the process of replication in eukaryotes. Although DNA polymerase can very easily replace internal RNA primers of the lagging strand with DNA, the replacement of the 5’ RNA primer requires the extension of the 3’ single-stranded parental DNA by telomerase.