Question

The ‘primer’ required to initiate synthesis of a new DNA strand consists of ______.

विकल्प

• an Okazaki fragment

• DNA

• a structural protein

• RNA

Answer 1

The ‘primer’ required to initiate the synthesis of a new DNA strand consists of RNA.

Explanation:

The synthesis of a new DNA strand cannot begin from scratch because DNA polymerase, the main enzyme responsible for replication, is unable to initiate the process. It requires a pre-existing 3’-OH (hydroxyl) group to attach the first nucleotide. To overcome this, an enzyme called primase (a type of RNA polymerase) synthesises a short stretch of RNA, typically 10 to 12 nucleotides long, known as a primer. This RNA primer provides the necessary starting point for DNA polymerase to bind and begin extending the new DNA chain. Once replication is underway, these RNA primers are eventually removed and replaced with DNA nucleotides to complete the sequence.