Question

Primers used for the process of polymerase chain reactions are

• A. double-stranded DNA oligonucleotide
• B. single-stranded RNA nucleotide
• C. single-stranded DNA nucleotide
• D. double-stranded DNA oligonucleotide

Answer 1

The correct option is C single-stranded DNA nucleotide

In PCR, the primers are designed according to the sequence of the single-stranded DNA template that has to be amplified. Primers are the short sequence of nucleotides that serve as a base for the formation of the new DNA strand. The main purpose of the primer is to provide the free 3’OH and facilitate the process of polymerase action.

Primers are designed for a specific DNA sequence that gives the specificity of the PCR amplification, meaning that particular template it is designed for will bind to its specific complementary sequence and initiate the process of synthesis of the new DNA. For each double-stranded DNA subjected to PCR, it will denature into two separate strands and hence to synthesise both the strands, two primers are loaded at 3’ end of both the templates.

Thus, the primer is a short, single-stranded DNA sequence which hybridises with the template DNA and defines the region of the DNA that needs to be amplified.