Biochemistry MCQs with correct answer %

Biochemistry MCQs D) A and B - correct answer What charged group(s) is/are present in glycine at a pH of 7? A) -NH3+ B) -COO- C) -NH2+ D) A and B E) A, B, and C B) -COO- - correct answer At a pH of 12, what charged group(s) is/are present in glycine? A) -NH3+ B) -COO- C) -NH2+ D) A and B E) A, B, and C A) FNC - correct answer Below is a list of five tripeptides identified by their single letter codes. They are listed as A, B, C, D, and E. Which tripeptide contains an amino acid capable of forming covalent disulfide bonds? A) FNC B) RGK C) VIL D) MDE E) SYT E) SYT - correct answer Below is a list of five tripeptides identified by their single letter codes. They are listed as A, B, C, D, and E. Which tripeptide has the most polar side chains? A) FNC B) RGK C) VIL D) MDE E) SYT B) interior due to the hydrophobic effect - correct answer Where are Trp and Phe found in a globular protein and why? A) exterior due to the hydrophilic effect B) interior due to the hydrophobic effect C) exterior forming polar H-bonds with water D) interior forming ionic bonds with other amino acids E) exterior forming ionic-polar bonds with water A) its structure - correct answer What determines a protein's function? A) its structure B) its gene sequence C) N-terminal amino acids D) None of the above. E) All of the above. E) All of the above. - correct answer Key properties of proteins include: A) a wide range of functional groups. B) an ability to possess either rigid or flexible structures as dictated by functional requirements. C) the ability to interact with other proteins. D) A and B. E) All of the above. B) It exhibits partial double-bond character, preventing rotation. - correct answer Why is the peptide bond planar? A) Bulky side chains prevent free rotation around the bond. B) It exhibits partial double-bond character, preventing rotation. C) Hydrogen bonding between the NH and C=O groups limits movement. D) None of the above. E) All of the above. C) phenylalanine - correct answer Which of the following amino acid residues would most likely be buried in the interior of a water-soluble, globular protein? A) aspartate B) serine C) phenylalanine D) lysine E) glutamine D) a series of repeatable random events where the lowest energy structure is maintained. - correct answer The folding of a protein into its native shape can best be described as: A) a random event. B) a random event catalyzed by ribosome proteins to maintain a low energy structure. C) a series of controlled folds with a few random-shaped structures. D) a series of repeatable random events where the lowest energy structure is maintained. E) an event where the highest possible energy state is stabilized with discrete folding intermediates. D) The structure is stabilized by H-bonding between the oxygen of the backbone carbonyl and the hydrogen of the backbone amine. - correct answer Your study group is trying to identify differences in the four levels of protein structure. Which of the following would you say is true of important stabilizing forces in secondary structure but not tertiary structure? A) The structure is stabilized by ionic attractions between oppositely charged side chains. B) The structure is stabilized by H-bonding between polar side chains. C) The structure is stabilized by hydrophobic interactions between nonpolar side chains. D) The structure is stabilized by H-bonding between the oxygen of the backbone carbonyl and the hydrogen of the backbone amine. E) None of these differentiate between secondary and tertiary structure. D) treat with ascorbic acid (vitamin C). - correct answer All of the following would disrupt quaternary structure except: A) increase the temperature. B) decrease the pH. C) add 8 m Urea. D) treat with ascorbic acid (vitamin C). E) treat with β-mercaptoethanol. B) catalytic activity. - correct answer When enzymes are purified, the assay is often based on: A) light absorbance. B) catalytic activity. C) pH. D) temperature changes. E) mRNA levels. C) SDS allows proteins to be separated on the basis of approximate mass. - correct answer What is the advantage of adding SDS to gel electrophoresis? A) SDS colors the proteins for visualization. B) SDS reduces disulfide bonds. C) SDS allows proteins to be separated on the basis of approximate mass. D) None of the above. E) All of the above. D) isoelectric focusing and SDS-PAGE - correct answer Two-dimensional electrophoresis is a combination of what two techniques? A) isoelectric focusing and affinity chromatography B) ion-exchange chromatography and SDS-PAGE C) affinity chromatography and SDS-PAGE D) isoelectric focusing and SDS-PAGE E) isoelectric focusing and ion-exchange chromatography D) All of the above. - correct answer Which of the following affects the sedimentation of a particle? A) mass B) shape C) the density of the solution D) All of the above. E) A and B B) the carboxyl side of Met residues. - correct answer Cyanogen bromide cleaves the peptide bond at: A) the carboxyl side of Arg and Lys residues. B) the carboxyl side of Met residues. C) the amino terminus. D) None of the above. E) All of the above. C) western blot - correct answer Which of the following techniques can be used to determine the size of a target protein? A) Edman degradation B) affinity chromatography C) western blot D) ELISA E) isoelectric focusing gel D) separate proteins based on attraction to another molecule. - correct answer Affinity chromatographs: A) allow high resolution and rapid separation. B) separate proteins based on size. C) separate proteins based on charge. D) separate proteins based on attraction to another molecule. E) separate proteins based on charge and size.