Quiz: Protein Structure and Function: NUTR641: Nutritional Biochemistry I (D01) Answered Fall 2024/2025.

Quiz: Protein Structure and Function: NUTR641: Nutritional Biochemistry I (D01) Quiz: Protein Structure and Function Score for this attempt: 80 out of 80  Q uestion 1 2 / 2 pts hydrogen bonding disulfide bridges ...

Quiz: Protein Structure and Function: NUTR641: Nutritional Biochemistry I (D01) Quiz: Protein Structure and Function Score for this attempt: 80 out of 80  Q uestion 1 2 / 2 pts hydrogen bonding disulfide bridges salt bridges the hydrophobic effect The quiz: Covers the Textbook material from Module 3: Week 3. Contains 40 multiple-choice questions. Is limited to 1 hour and 30 minutes. Allows 2 attempts. Is worth 80 points. Submit this assignment by 11:59 p.m. (ET) on Sunday of Module 3: Week 3. Noncovalent forces that stabilize protein structure include all of the following except ________. electrostatic interactions with metal ions  Q uestion 2 2 / 2 pts protonated and neutral protonated and positively charged deprotonated and neutral deprotonated and negatively charged none of these choices Q uestion 3 2 / 2 pts protonated and neutral protonated and positively charged deprotonated and neutral deprotonated and negatively charged none of these choices  Q uestion 4 2 / 2 pts transferase lyase hydrolase oxidoreductase ligase  Q uestion 5 2 / 2 pts At a pH above its pKa, the phenolic group of tyrosine is ________. At a pH above its pKa, the R-group of Asp is ________. Chymotrypsin catalyzes the hydrolysis of a peptide bond and is therefore categorized as a ________. Which of the following occurs in hemoglobin upon oxygen binding? the heme Fe2+ is pulled out of the plane of the heme group hemoglobin changes from the R state to the T state the central cavity between the four subunits is decreased in size the His coordinated to the heme Fe2+ is pushed away from the heme group all of the above occur  Q uestion 6 2 / 2 pts factor VII prothrombin factor X factor VIIa thrombin Q uestion 7 2 / 2 pts both β subunits simultaneously switch first followed by both α subunits both α subunits simultaneously switch first followed by both β subunits each subunit switches only upon oxygen binding to the particular subunit all four subunits switch simultaneously none of the above  Q uestion 8 2 / 2 pts disulfide bonds hydrogen bonds hydrophobic interactions salt bridges Which protein in the blood is responsible for converting fibrinogen to fibrin? Which of the following explains the conversion of hemoglobin subunits from deoxy to oxy state? Which of the following interactions would be involved in quaternary structure? all of these choices  Q uestion 9 2 / 2 pts movement of a mitochondria in a cardiac cell movement of a lipid-filled vesicle within an intestinal cell movement of a neurotransmitter vesicle down the axon of a nerve cell movement of a glucose filled vesicle to the membrane of a liver cell none of the above Q uestion 10 2 / 2 pts electrophilic catalysis covalent catalysis acid-base catalysis metal ion catalysis none of the above  Q uestion 11 2 / 2 pts CO binds to Hb about 5 times more strongly than oxygen CO binds to Hb with less affinity than oxygen CO binds to Hb about 250 times more strongly than oxygen CO binds to Hb with an affinity about the same as oxygen none of the above  Q uestion 12 2 / 2 pts Which of the following represents the longest distance traveled by a kinesin-vesicle complex? An enzyme that forms a covalent bond with its substrate during the course of a reaction is considered to undergo ________. Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO? Asp → Asn Asp → Glu Asp → Lys Asp → Ser Asp → His  Q uestion 13 2 / 2 pts tubulin; GTP actin; ATP another myosin molecule; ATP kinesin; GTP none of the above Q uestion 14 2 / 2 pts protonated and neutral protonated and positively charged deprotonated and neutral deprotonated and negatively charged none of these choices  Q uestion 15 2 / 2 pts Asp residue Gln residue If the Asp in the chymotrypsin active site was mutated to another amino acid, which of the following would be considered an invisible mutation in that it is least likely to impact the function of the enzyme? Each myosin head contains a binding site for ________ and a binding site for ________. At a pH above its pKa, the ε-amino group of lysine is ________. In an enzyme mechanism that generates a negative charge in the transition state, which of the following would be most effective to have in the active site of the enzyme? transition metal cation transition metal anion none of the above  Q uestion 16 2 / 2 pts tubulin; proteins in the membrane of a vesicle proteins in the membrane of a vesicle; actin collagen fibers; proteins in the cell membrane proteins in the membrane of an organelle; tubulin none of the above Q uestion 17 2 / 2 pts allosteric cooperative induced-fit ligand-activated none of the above  Q uestion 18 2 / 2 pts coenzyme metal ion cosubstrate prosthetic group cofactor  The heads of kinesin bind to ________; the light chains of kinesin bind to ________. Proteins such as hemoglobin are known as ________ proteins since binding of a molecule to one site alter binding to other sites. An organic molecule that is tightly bound to an enzyme and participates in an enzyme catalyzed reaction is specifically referred to as a ________. 13 Question 19 2 / 2 pts primary secondary tertiary quaternary none of these choices Q uestion 20 2 / 2 pts lysine arginine glutamine glutamate proline  Q uestion 21 2 / 2 pts sigmoidal; hyperbolic hyperbolic; sigmoidal hyperbolic; hyperbolic hyperbolic; exponential sigmoidal; sigmoidal  Q uestion 22 2 / 2 pts it causes a localized increase in the concentration of reactants What level of protein structure is characterized by the three dimensional structure of an entire polypeptide including all amino acid side chains? Which amino acid does not have a primary α-amino group? A plot of the binding of oxygen to myoglobin as a function of pO2 gives a ________ shape; a similar plot for hemoglobin gives a ________ shape. How does a catalyst increase the rate of a reaction? it allows reacting molecules to more easily form the transition state it increases the temperature of the reaction it makes the reaction more exergonic none of the above  Q uestion 23 2 / 2 pts they do not contain the cofactors required for catalysis the pH of their environment is not optimal for activity their active sites are distorted and incapable of enzymatic activity they are the product of mutated genes none of the above Q uestion 24 2 / 2 pts increase the temperature add a catalyst increase or decrease the pH increase the concentrations of the reactants none of the above  Q uestion 25 2 / 2 pts Leu; Ser Thr; His Leu; Ile Val; Phe none of these choices Z  ymogens are not enzymatically active because ________. Which of the following is the most effective way to increase the rate of a biochemical reaction? For a globular protein that is found in the cytosol, ________ would most likely be found in the proteins interior while ________ would most likely be found on the surface. Question 26 2 / 2 pts ligase oxidoreductase hydrolase lyase isomerase Q uestion 27 2 / 2 pts Arg Cys Ile Gly Pro  Q uestion 28 2 / 2 pts aggregates tertiary structure primary structure peptide bonds none of these choices  Q uestion 29 2 / 2 pts Met Ser Enzyme X catalyzes the addition of a hydroxyl group to substrate Y. In the process a metal cofactor is reduced and then reoxidized. What class of enzyme is X? Which of the 20 standard amino acids is optically inactive? Molecular chaperones assist proteins in the formation of ________. Which of the following amino acids has a thiol group in its side chain? Asn Tyr Cys  Q uestion 30 2 / 2 pts Cu2+ Cu+ Fe2+ Fe3+ none of the above Q uestion 31 2 / 2 pts transition states substrates intermediates products all are bound very tightly  Q uestion 32 2 / 2 pts Ser Cys Thr His Lys  Q uestion 33 2 / 2 pts The central ion of the heme group of hemoglobin is ________. Of all the species that enzymes bind, they are thought to bind most tightly to ________. What amino acid performs the nucleophilic attack during the chymotrypsin mechanism? mass spectrometry X-ray crystallography electron crystallography NMR spectroscopy none of these choices  Q uestion 34 2 / 2 pts elastase: cleaves on the C-terminal side of Phe, Trp or Tyr chymotrypsin: cleaves on the C-terminal side of Lys or Arg cyanogen bromide: cleaves on the C-terminal side of Met trypsin: cleaves on the C-terminal side of Ala or Val none of these choices Q uestion 35 2 / 2 pts KYG GYA KYA DYA DYG  Q uestion 36 2 / 2 pts Lys Asn Glu Ser A technique for determining protein structure where the protein is in solution is ________. Which of the following methods for cleaving a protein is properly identified? Which of the following tripeptides would be expected to be the most hydrophobic? In the enzyme catalyzed decarboxylation of acetoacetate, a Schiff base is formed between the ketone of acetoacetate and a ________ residue in the active site of the enzyme. Arg  Q uestion 37 2 / 2 pts Lys His Cys Ser Gln Q uestion 38 2 / 2 pts irreversible; reversible reversible; irreversible reversible; reversible irreversible; irreversible none of the above since antithrombin is not an inhibitor of thrombin  Q uestion 39 2 / 2 pts 3.33 6 5 4 none of these choices  Q uestion 40 2 / 2 pts Which amino acid is critical for crosslinking of collagen trimers? Conversion of factor X to factor Xa represents a(n) ________ form of activation; binding of antithrombin to thrombin represents a(n) ________ form of inhibition. If an α-helical region of a protein contained 18 amino acid residues, how many helical turns would be present? Which of the following is a feature of protease inhibitor specific for trypsin? high affinity for the enzyme active site inability to form the tetrahedral intermediate contains a positive charge to mimic the charge of the substrate ability to interact with the Ser of the catalytic triad all of the above Quiz Score: 80 out of 80