Chapter 13, Problem 13PDQ

A short RNA molecule was isolated that demonstrated a hyperchromic shift (see Chapter 10), indicating secondary structure. Its sequence was determined to be

5′-AGGCGCCGACUCUACU-3′

1. (a) Propose a two-dimensional model for this molecule.
2. (b) What DNA sequence would give rise to this RNA molecule through transcription?
3. (c) If the molecule were a tRNA fragment containing a CGA anticodon, what would the corresponding codon be?
4. (d) If the molecule were an internal part of a message, what amino acid sequence would result from it following translation?

   (Refer to the code chart in Figure 13.7.)

FIGURE 13.7 The genetic coding dictionary. AUG encodes methionine, which initiates most polypeptide chains. All other amino acids except tryptophan, which is encoded only by UGG, are represented by two to six triplets. The triplets UAA, UAG, and UGA are termination signals and do not encode any amino acids. Three-letter abbreviations for each amino acid are commonly used (see Figure 14.17) and are depicted here.