Paper 2 · November 2004 · Genetic Engineering
Name the class of enzyme used in genetic engineering to cut a DNA molecule at a specific base sequence.
Model answer
restriction enzyme
Also accepted: restriction endonuclease, restriction enzymes, restriction endonucleases
Explanation
These enzymes recognise a short palindromic sequence and cut both strands there, so the same fragment is released every time. That reliability is what lets the same gene be cut out of a chromosome again and again.
Derived from ZIMSEC Biology Paper 2, Nov 2004, Q3