Chapter 1, Problem 6P

RNA shares with proteins the ability to fold into complex three-dimensional shapes. As a result, RNA molecules can, like protein molecules, catalyze biochemical reactions (that is, both kinds of molecules can act as enzymes, or biological catalysts). These statements are not true of DNA. Why can some RNA molecules act as enzymes whereas DNA molecules cannot? (Hint: Most RNA molecules consist of a single strand of nucleotides while most DNA molecules are double helixes made of two strands of nucleotides.)