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Unformatted text preview: Chapter 2 1. Which of the following is true regarding the chirality of amino acids found in proteins? a. Only L amino acids are found in proteins. b. Only D amino acids are found in proteins. c. Proteins contain both D and L amino acids. 2. Of the 20 amino acids from which proteins are made, which is most likely to be present with its R-group in a mixture of ionization states near physiological pH? a. Tyr b. His c. Glu 3. The conversion of cysteine to cystine is what kind of reaction? a. an oxidation b. a reduction c. an addition 4. Which of the following is NOT true of peptide bonds? a. They tend to be planar. b. They are generally in the trans and rarely in the cis configuration c. They tend to have the amide nitrogen protonated to give a positive charge. 5 . What do -helices and -sheets have in common? α β a. Both are stabilized by hydrogen bonding involving the same types of groups b. The same amino acids stabilize both forms of secondary structure. c. The length of a 10-amino acid -helix and -sheet strand will be the same α β 6. Water-soluble proteins such as myoglobin tend to a. fold such that hydrophobic amino acid R-groups are on the interior of the protein and hydrophilic groups are on the outside b. fold such that hydrophilic amino acid R-groups are on the interior of the protein and hydrophobic groups are on the outside c. fold such that all peptide bonds form hydrogen bonds with water 7. -helices and -sheets are often found to be amphipathic. This means that α β a. They have positive charges on one side and negative charges on the other. b. They have large R-groups on one side and small R-groups on the other as small groups are b....
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This note was uploaded on 04/17/2008 for the course CHE 312 taught by Professor Disney during the Spring '08 term at SUNY Buffalo.
- Spring '08