Question

Eukaryotes solve the problem of replicating the ends of their linear chromosomes by:

A. Using a protein as primer
B. Enzyme activity that uses an RNA template and reverse transcription in a series of repeat cycles
C. All of the listed solution
D. Terminal redundancy whereby each end of the chromosome is duplicated allowing recombination

Answer 1

B. Enzyme activity that uses an RNA template and reverse transcription in a series of repeat cycles

Step-by-step explanation:

In eukaryotic linear chromosomes, the lagging strands at terminal do not get replicated in usual manner because it is a special case. The problem with terminal lagging strand (which is synthesized in a discontinuous manner) is that there is no template for its primer synthesis. In such scenario, an enzyme known as telomerase recognizes telomeres and extend it's 3' overhang through its reverse transcriptase activity which is facilitated by it's RNA component specifically. This RNA has repeat sequences which are complimentary to the telomeric repeats and therefore it acts as a template for the extension of 3' overhang.

Here, it may be noted that the leading strand does not require any terminal primer for replication because the replication process for it is continuous i.e. only one primer is required which is synthesized in the beginning of replication so there is no need of synthesizing primer again and again.