Question

Which one of the following is considered as molecular scissors in modern biotechnology?

• A. Reverse transcriptase
• B. Taq polymerases
• C. Alkaline phosphatases
• D. Restriction endonucleases

Hint:

Biotech toolkit: Restriction enzymes = cut, Ligase = join, Polymerase = synthesize.

Answer 1

The Correct Option is D

Concept:
Modern biotechnology relies on enzymes that manipulate DNA. Among these, certain enzymes can cut DNA at specific sequences, which is essential for genetic engineering.

Step 1: Understand “molecular scissors”. “Molecular scissors” refers to enzymes that can cut DNA at specific recognition sites.

Step 2: Identify the correct enzyme. Restriction endonucleases are enzymes that recognize specific palindromic DNA sequences and cleave the DNA at those sites. \[ \text{Restriction enzymes} \rightarrow \text{Cut DNA at specific sites} \]

Step 3: Analyze the given options.
• (A) Reverse transcriptase → Synthesizes DNA from RNA $\times$
• (B) Taq polymerase → DNA synthesis during PCR $\times$
• (C) Alkaline phosphatase → Removes phosphate groups $\times$
• (D) Restriction endonucleases → Cut DNA (molecular scissors) \checkmark

Step 4: Conclusion. Thus, the enzyme known as molecular scissors is: \[ \text{Restriction endonucleases} \]