Une Biochem Unit 1

UNE BIOCHEM UNIT 1 Domains are common structural elements that retain a particular function within the protein. Give an example fo a protein domain. An arrangement of Beta-strands connected by a-helices (BaBaBa) Define what a protein domain is A section os a protein structure sufficient to perform a particular chemical or physical task Chymotrypsin is a protease that cleaves peptide bonds. It is characterized as which of the following classes of enzymes? Hydrolases Hemoglobin bound to heme is termed a holoprotein. The heme or porphyrin ring is required for oxygen binding and it is defined as which group? prosthetic group 1. Covalent catalysis is used by many enzymes to cleave peptide bonds. Which amino acid would not facilitate this type of catalysis? (Think of the structure of the R-Group of these amino acids) Valine How do most enzymes reduce the activation energy needed to move a reaction forward? Providing an active site most complementary the transition state Prosthetic groups are complex non protein molecules that participate in catalysis by providing functional groups that form a covalent intermediate between the enzyme and the substrate. Give an example of a coenzyme or cofactor that participates in the covalent catalysis reaction. Pyridoxal phosphate 1. Movement of ammonia from an amino acid to an a-keto acid involves a family of enzymes best categorized as? Transferases a. The green line shows enzyme kinetics with the addition of a noncompetitive inhibitor In the mage shown the blue line indicates enzyme kinetics with no inhibitor present. Based on this information which of the following is true? a. The green line shows enzyme kinetics with the addition of a noncompetitive inhibitor b. The red line shows enzyme kinetics with the addition of a non competitive inhibitior c. The green line shows enzyme kinetics with the addition of a competitive inhibitor d. More information is needed regarding the addition of an inhibitor c. It reduces the catalytic activity of the enzyme A 28-year-old male is recently diagnosed with HIV. As part of his treatment he is prescribed Nevirapine which interfered with retroviral reverse transcriptase enzyme. Using the graph below, which of the following best describes the impact of this drug on its target? a. It increases the Km of its substrate b. It decreases the Km of its substrate c. It reduces the catalytic activity of the enzyme d. It increases the rate of the reaction c. Glucokinase has a higher Km than hexokinase Use the figure below to compare the activities of glucokinase and hexokinase. Based on this information, which of the following is a true statement? a. Glucokinase has a higher affinity for glucose than hexokinase b. Glucose concentrations do not impact enzyme activity, but the expression patterns dictate their activity c. Glucokinase has a higher Km than hexokinase d. Hexokinase has a higher Km than glucokinase An example of enzyme activation by cleavage is best illustrated by Activation of chymotrypsinogen to chymotrypsin 1. Children with cystinosis have growth delay and both renal and ocular issues due to accumulation of cysteine in cellular lysosomes. The defect involves a specific lysosomal membrane receptor that facilitates cysteine removal from the cell. An effective therapy has been administration of a drug with a similar structure to cysteine. This therapy reflects the general principle that competitive inhibitors typically resemble the structure of Substrates or ligands that bind the active site 1. An enzyme is participating in a general acid-base catalysis reaction with an optimal reaction pH of 6.0. If acid is added to the environment reducing the pH to 3, what is the likely impact to the rate of reaction? The rate of the reaction is likely to decrease as the pH is out of optimal catalytic range The association of DNA and histones can be modified by histone acetylation. A decrease in histone acetylation will have which of the following impacts on the association of DNA and histones? Increase DNA; histone association If a mutation is made within the active site of an enzyme resulting in a decrease in Km, what will happen with respect to the enzyme kinetics? The enzyme will require a lower substrate concentration to reach 1/2 Vmax The fully reduced quinol form of CoQ contains what combination of electrons and protons? 2 electrons and 2 protons What component of the electron transport chain is not bound to the mitochondrial membrane? CoQ The malate-aspartate shuttle is used to move reducing equivalents of cytosolic NADH into the mitochondira where it can be oxidized. What compound is used to move the reducing equivalents from cytosolic NADH into the mitochondria? Malate As electrons flow through complexes in the inner mitochondrial membrane, protons are pumped from the matric to the intermembrane space. Id the pH higher or lower in the intermembrane space when compared to the matrix? The pH is lower in the intermembrane space and higher in the matrix 1. The malate-asparate shuttle system generates _______ molecules of _____ in ________ per each NADH from ________ 2.5; ATP; MITOCHONDRIA; GLYCOLYSIS The glycerophosphate shuttle is the major shuttle of most tissues. What best describes the transfer of electrons by this shuttle? Electrons are directly transferred from glycerol 3-phosphate to an FAD containing glycerol phosphate dehydrogenase What is the correct and complete electron transfer pathway necessary for oxidative phosphorylation? NADH---complex I---CoQ---complex III---cyt c---complex IV Heat can be generated in the brown adipose tissue of hibernating mammals. What is the mechanism by which this occurs? Expression of a protein that uncouples the ETC