Question

In recombinant DNA technology, which enzyme is used to cut DNA at specific recognition sites to produce restriction fragments?

• A. DNA polymerase
• B. Restriction endonuclease
• C. Ligase
• D. Reverse transcriptase

Hint:

In recombinant DNA technology, remember that restriction endonucleases cut DNA at specific sites, ligase joins DNA fragments, and DNA polymerase amplifies DNA. Each enzyme has a distinct role in genetic engineering.

Answer 1

The Correct Option is B

In recombinant DNA technology, restriction endonucleases (or restriction enzymes) cleave DNA at precise recognition sites, generating restriction fragments with either sticky or blunt ends. These enzymes identify palindromic DNA sequences and break phosphodiester bonds, facilitating the insertion of exogenous DNA into vectors such as plasmids for cloning or genetic engineering.
The functions of other enzymes are:
- DNA polymerase: Constructs new DNA strands during replication or in processes like PCR; it does not cut DNA.
- Ligase: Connects DNA fragments by creating phosphodiester bonds, employed to repair breaks in recombinant DNA molecules.
- Reverse transcriptase: Generates DNA from an RNA template, utilized in cDNA library construction; it does not cut DNA.
Therefore, the enzyme responsible for cleaving DNA at specific recognition sites in recombinant DNA technology is restriction endonuclease.