Solved by a verified expert:The process of protein folding involves:a. a progressive random search through multiple distinct complete conformations that eventually results in the native protein.b. a rapid “collapse'” of the extended polypeptide chain into the fully folded native conformation.c. formation of a number of final structures simultaneously, with the incorrect structures removed by proteolysis.d. progressive stabilization of correct secondary structural intermediates, and unfolding of incorrect structures, until the final structure is attained.e. an increase in free energy until the proper final structure is reached.2. Which of the following techniques is most useful for fractionating a heterogeneous protein mixture by sizea. Affinity chromatographyb. Edman degradationc. Gel-filtration chromatographyd. Ion-exchange chromatographye. Isoelectric focusing3. Which of the following determines a protein’s native structurea. The protein’s concentration in solutionb. The rate at which the protein is translatedc. The protein’s linear amino acid sequenced. The identity of the chaperone that guides the protein’s foldinge. Both the protein’s linear amino acid sequence and the identity of the chaperone that guides its folding4. Which of the following secondary structures is most likely to be found in a membrane-embedded portion of a proteina. An alpha helix composed entirely of hydrophobic residuesb. An alpha helical coiled coilc. An single extended beta strandd. An open antiparallel beta sheet composed of hydrophobic residuese. An open parallel beta sheet composed of hydrophilic residues5. The relative mobility of different proteins during SDS-polyacrylamide gel electrophoresis is primarily determined by which property of the proteinsa. Antigenicityb. Hydrophobicityc. Isoelectric pointd. Masse. Native structure6. Which of the following statements regarding peptide bonds is least accuratea. Peptide bonds tend to form a planar structure.b. Peptide bonds are thermodynamically unstable, but kinetically stable.c. Favored conformation of peptide bonds is with the sequential alpha carbons in the cis position.d. Water is released during the formation of peptide bonds.e. At equilibrium, the peptide-bond-forming reaction favors hydrolysis.7. Which of the following best describes the arrangement of amino acid side chains in an alpha helixa. The side chains point outward away from the helical axis.b. The side chains point inward toward the center of the helix.c. The side chains point toward the N-terminal end of the helix.d. The side chains point toward the C-terminal end of the helix.e. The side chains point toward the nearest beta sheet.
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