2011Exam2KEY

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Unformatted text preview: ting in the reverse direction. It employs the enzyme hexokinase. It is one of the ways that mammals maintain normal blood glucose levels between meals. It produces metabolic energy (ATP or GTP). 1 Exam 2 Chem 423 Spring 2011 Name KEY 6. During prolonged exercise when muscle cells must function anaerobically, which of the following is true? A) glycolysis cannot occur under anaerobic conditions. B) no ATP can be generated by metabolism under anaerobic conditions. C) under anaerobic conditions most of the pyruvate generated as a result of glycolysis is reduced to lactate rather than being oxidized by the citric acid cycle. D) under anaerobic conditions most of the pyruvate generated as a result of glycolysis is oxidized by the citric acid cycle rather than reduced to lactate. 7. Which of the following conditions will inhibit oxygen consumption in a sample containing mitochondrial membranes, NADH, and ADP: A) B) C) D) E) Mitochondrial membranes are leaky. Addition of a lipophilic weak acid. Addition of DCCD, which blocks proton flow through ATP synthase. None of the above. All of the above. II. Short Answer: Write neatly in the space provided. 8. (16 points) Soluble alpha/beta barrel proteins (like the picture) consist of hydrophobic beta strands (with sidechains filling the center of the protein) surrounded by amphipathic alpha helices. Suppose you wanted to design an alpha/beta barrel protein that would form an aqueous transmembrane channel (hole in the center filled with water). Describe some requirements for designing such a membrane protein. a) What types of alpha helices and beta strands (polar, nonpolar, amphipathic) would you use and why? Amphipathic beta strands and nonpolar alpha helices. Helices are nonpolar to be compatible with nonpolar lipid on the outside and to pack against nonpolar side of beta strands on the inside. Polar side of beta strands points inward to f...
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This note was uploaded on 08/24/2013 for the course CHEM 423 taught by Professor Thompson during the Spring '11 term at UMass (Amherst).

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