Draw the complete structure of uridine 5′-phosphate, one of the four major ribonucleotides.

What type of bonding is responsible for the formation of the two types of secondary structures?

The primary amino acid sequence of a stretch of polypeptide is Asp-Glu-Pro-Lys-His-Arg. Would you expect this portion of the polypeptide to form an alpha helix at pH=5? Provide 3 reasons to justify your answer.

Human ribonucleotide reductase has two allosteric sites, the S site and the A site. What is the function of each? How does this compare with the E. Coli enzyme discussed in the text?

Consider the hydrogen bonding pattern of an α-helix with the following sequence: HLRTNAGCSY Asparagine’s amide hydrogen is hydrogen bonded to:       a. Serine’s side chain   b. Histidine’s backbone carbonyl oxygen   c. Cysteine’s backbone carbonyl oxygen   d. Serine’s backbone carbonyl oxygen   e. Histidine’s side chain

Draw the structure of a dinucleotide formed by joining the 3'-OH group of dGMP to the 5'-phosphate in dAMP. O=P. HO

Which of the molecules of RNA is the most likely to fold into a specific structure as a result of intramolecular (within itself) base-pairing?  Explain. 5′-CCCUAAAAAAAAAAAAAAAAUUUUUUUUUUUUUUUUAGGG-3′ 5′-UGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUG-3′ 5′-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA-3′ 5′-GGAAAAGGAGAUGGGCAAGGGGAAAAGGAGAUGGGCAAGG-3′

Draw the molecular formula of the covalently modifi ed histone side chain of acetyllysine. How does this modifi cation alter the chemical properties of the side chain?