UNE Biochem week 1 quiz already passed

UNE Biochem week 1 quiz already passed An enzyme has a mutation within the substrate binding site that reduces the binding of the coenzyme needed for covalent catalysis. Which of the following is likely to result as a consequence of this mutation? the enzyme will not be able to form the transition state complex Covalent catalysis is used by many enzymes to cleave peptide bonds. Which of the following amino acids would not facilitate this type of catalysis? (Think of the structure of the R-group of these amino acids) Valine The R-group on valine does not have an active group to participate in covalent catalysis. The most commonly participating amino acids are cysteine, serine and histidine. A 55-year old man is brought to the emergency room with a chief complaint of chest pain and tingling in his left arm. Elevation of which of the following enzymes in circulation would be most indicative of a myocardial infarction? Troponin MI is diagnosed by elevation of troponin, cardiac specific troponins would be the most accurate answer for this diagnosis. Amylase and lipase would indicate pancreatitis; elevation of lactate dehydrogenase is non-specific for muscle damage. Although LDH may be elevated, in the case of an MI it would not be a definitive indicator. Prosthetic groups are complex nonprotein molecules that participate in catalysis by providing functional groups that form a covalent intermediate between the enzyme and the substrate. Which of the following is an example of a coenzyme or cofactor that participates in a covalent catalysis reaction? Pyridoxal phosphate Amino transferases are commonly used in the movement of ammonia and use the covalent catalysis "ping-pong method". NADH and FAD are commonly used in oxidation reduction reactions and ATP is typically an energy carrier within an reaction. Movement of ammonia from an amino acid to an α-keto acid involves a family of enzymes best categorized as which of the following? Transferases Amino transferases are commonly used in the movement of ammonia and use the covalent catalysis "ping-pong method" Which of the following best describes a protein domain? A section of a protein structure sufficient to perform a particular chemical or physical task By definition, domains would include multiple elements of secondary structure to generate a region on the protein with a distinct function and spatial arrangement. None of the other choices fit this definition. Changes in the physiological variables listed below can alter the affinity of hemoglobin for oxygen. Which of the following will lower the affinity of hemoglobin for oxygen? Increase in 2,3 bisphosphoglycerate (BPG) A decreased affinity will increase the rate of oxygen delivery to the tissues. This will occur when pH is low, there is an increase in CO2, protons or 2,3 BPG. The other scenarios (a, c, d) will all increase the affinity for O2. Which amino acid would not be commonly found in the middle of a an α-helical domain? Proline Proline is a non-traditional amino acid. Peptide bond formation with this amino acid generates a kink or turn in a primary amino acid strand. If introduced in a helix it will destabilized the hydrogen bonding between resides in the helix.