2024 Molecular Basis of InheritanceDirectionality of DNA Polymerase Activity Medium Question 17 of 200 in Molecular Basis of Inheritance

Which of the following statement is correct regarding the process of replication in $E.\ coli$?

A The DNA dependent DNA polymerase catalyses polymerization in $5'\rightarrow3'$ as well as $3'\rightarrow5'$ direction.
B The DNA dependent DNA polymerase catalyses polymerization in $5'\rightarrow3'$ direction.
C The DNA dependent DNA polymerase catalyses polymerization in one direction, that is $3'\rightarrow5'$.
D The DNA dependent RNA polymerase catalyases polymerization in one direction, that is $5'\rightarrow3'$.

The answer is B.

Solution

DNA-dependent DNA polymerase catalyses polymerisation only in one direction, $5' \rightarrow 3'$. It adds nucleotides to the free 3'-OH end of the growing strand, which is why replication is continuous on one strand and discontinuous on the other.

Concept Direction of nucleotide addition by DNA polymerase in E. coli

Molecular Basis of Inheritance in past papers

200 questions from this chapter have appeared across 27 exam years.