[Campbell Biology P.490] Which of the following sequences in double-stranded DNA is most lik... | Practice Question

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?

  • A: 5'-AAGG-3' 3'-TTCC-5'
  • B: 5'-GGCC-3' 3'-CCGG-5'
  • C: 5'-ACCA-3' 3'-TGGT-5'
  • D: 5'-AAAA-3' 3'-TTTT-5'

Explanation

Restriction enzymes recognize specific DNA sequences, most of which are palindromic. A palindromic sequence reads the same forwards on one strand 5' to 3' as it does backwards on the complementary strand also 5' to 3' . For option B, reading 5'-GGCC-3' on the top strand and 5'-GGCC-3' on the bottom strand reading 3'-CCGG-5' from right to left confirms it is a palindrome.