Question

All of the following statements about DNA replication are true except

• A. DNA replication begins with an RNA primer.
• B. Hydrogen bonds must be broken for replication to occur.
• C. DNA replication begins at the promoter.
• D. Bacterial DNA replication proceeds in a circular fashion.
• E. One half of a new DNA strand must be assembled as small pieces instead of a continuous piece.

Answer 1

The correct option is C DNA replication begins at the promoter.

A. Initiation of DNA synthesis always requires a smaller segment of RNA called RNA primer. It is synthesized by enzyme primase.

B. The two strands of DNA double helix unwind with the help of DNA unwinding protein, called helicase. The unwinding occurs as this protein begins its binding with DNA strands, thus, breaking the hydrogen bonds between complementary nitrogenous bases.

C. DNA replication begins at certain fixed unique points and is called origin.

D. The chromosomes of bacteria are circular. Bacterial DNA replication occurs in a bidirectional way and proceeds with two replication forks in a circular manner.

E. Only one strand of DNA shows continuous replication which is called the leading strand. The other strand, called the lagging strand, replicates in a discontinuous manner by synthesizing short fragments called Okazaki fragments which are later joined by DNA ligase.

Hence, statement C is incorrect. So, the correct answer is 'DNA replication begins at the promoter'.