Final Questions in BioChem

1. Which of the following amino acids is the most soluble in water at pH 7.0? A. Glutamate B. Tryptophan C. Leucine D. Tyrosine E. Phenylalanine 2. The folded states of globular proteins in aqueous solutions are ...

1. Which of the following amino acids is the most soluble in water at pH 7.0? A. Glutamate B. Tryptophan C. Leucine D. Tyrosine E. Phenylalanine 2. The folded states of globular proteins in aqueous solutions are stabilized primarily by ______. A. hydrophobic interactions B. peptide bonds C. phosphodiester bonds D. ionic bonds E. disulfide bonds 3. Which of these statements about enzyme-catalyzed reactions that obey Michaelis-Menten kinetics is false? A. At saturating levels of substrate, the rate of an enzyme-catalyzed reaction is proportional to the enzyme concentration. B. The Michaelis-Menten constant Km equals the [S] at which V = 1/2 Vmax. C. If enough substrate is added, the normal Vmax of a reaction can be attained even in the presence of a competitive inhibitor. D. The rate of a reaction decreases steadily with time as substrate is depleted. E. The activation energy for the catalyzed reaction is the same as for the uncatalyzed reaction, but the equilibrium constant is more favorable in the enzyme-catalyzed reaction. 4. The most efficient substrate of an enzyme is usually considered to be the substrate with the ________. A. largest kcat B. largest Km C. largest kcat/Km D. smallest kcat/Km E. smallest Km 7. Certain restriction enzymes produce cohesive (sticky) ends. This means that they: A. cut in regions of high GC content, leaving ends that can form more hydrogen bonds than ends of high AT content. B. make a staggered double-strand cut, leaving ends with a few nucleotides of single-stranded DNA protruding. C. cut both DNA strands at the same base pair. D. stick tightly to the ends of the DNA it has cut. E. have none of the above characteristics.