Question

Identify the wrong statement with regard to restriction enzymes.

• A. They are useful in genetic engineering
• B. Sticky ends can be joined by using DNA ligases
• C. Each restriction enzyme functions by inspecting the length of a DNA sequence
• D. They cut the strand of DNA at palindromic sites

Answer 1

The correct option is B Sticky ends can be joined by using DNA ligases

(a) Genetic engineering or recombinant DNA technology can be accomplished only if we have the key tools, i.e., restriction enzymes, polymerase enzymes, ligases, vectors and the host organism.

(b) The sticky ends in DNA that result from the action of restriction endonucleases can be joined by DNA ligases, not by restriction enzymes. So, this statement does not apply to restriction enzymes and hence is the correct option for the question.

(c) Restriction enzymes begin their action by first scanning the length of the DNA sequence and then recognising a specific sequence. This specific base sequence is known as the recognition sequence.

(d) Each restriction endonuclease recognises a specific recognition sites and cut the DNA strand at palindromic sites.