Question

Which one is regarded as a molecular scissor in biotechnology?

• A. Reverse transcriptase
• B. Restriction endonuclease
• C. Taq polymerase
• D. Topoisomerase

Answer 1

The correct option is B Restriction endonuclease

Restriction enzymes are the enzymes that can cleave or cut a DNA molecule within certain specific sites that have a specific base sequence. These are used in recombinant DNA technology to produce cuts in vector and other DNA molecules to obtain chimeric DNA. Hence, these are also known as molecular scissors.
A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription.
Taq polymerase is a thermostable DNA polymerase. Taq polymerase is able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR.
Topoisomerases are enzymes that participate in the overwinding or underwinding of DNA. The winding problem of DNA arises due to the intertwined nature of its double-helical structure. During DNA replication and transcription, DNA becomes overwound ahead of a replication fork.