Question 50

Question:

A scientist wishes to insert her gene of interest into a yeast vector. She decides to use a restriction endonuclease that cleaves the vector at a palindromic recognition site leaving sticky ends. Which of the following is a possible recognition site for the restriction enzyme?

Correct Answer: C.  5′-CAATTG, 3′-GTTAAC

Don’t worry — you don’t need to memorize the recognition sequences! You simply need to know that restriction enzymes that splice at recognition sites are almost always palindromic. There are some restriction enzymes that cut outside the recognition site; these do not necessarily have palindromic recognition sites. Here, 5′-CAATTG & 3′-GTTAAC is the only answer choice with a palindromic sequence.