10. In a protein, the amino acid pairs below are near each other in the tertiary structure. For each pair briefly describe (10 words or less per pair) what kind of interaction is likely to occur at pH 7.4. If no interaction is likely clearly state so. a. Leu-Val b. Trp-Asp c. Ser-Gln d. Phe-Gln

3

The quaternary structure of a protein results from (choose the best answer) O a mutation O a prion such as the one that causes the scrapie disease in sheep O a combination of multiple lipid subunits a combination of polysaccharide subunits O a combination of two or more protein subunits

1. Is there more than one way to fold a protein, given the conflicting demands of the different "R" groups and the protein existing in a watery environment? 2. Explain what an R group is. 3. Compare the backbone of a polypeptide with that of a nucleic acid. 4. Proteins perform critical functions in all of our cells. Without proteins, life wouldn’t exist. Think of some specific proteins and describe what function they perform.  5. Explain the difference between secondary and tertiary protein structures.