BIOC 3560 Final Exam Questions With Answers Latest Updated 2024 (GRADED)

BIOC 3560 Final Exam Questions With Answers Latest Updated 2024 (GRADED) In the voltage-gated sodium channel, a. helix S6 is the voltage sensor b. helix S4 is the voltage sensor c. helix S4 contains the inactivation gate d. one subunit is responsible for activation e. one subunit is responsible for selectivity 2. Which of the following best describes the effects of insulin signaling on glycogen synthase kinase 3 (GSK3) and glucose transporters in liver cells? a. inactivation of GSK3 and inhibition of GluT4 transporters b. inactivation of GSK3 and internalization of GluT4 transporters c. inactivation of GSK3 and movement of GluT4 transporters to the cell surface d. activation of GSK3 and movement of GluT4 transporter to the cell surface e. activation of GSK3 and internalization of GluT4 transporters 3. When applied to isolated kidney tissue, ouabain (a toxin that blocks the Na+ / K+ ATPase) inhibits O2 consumption by 40%. This means that in kidney a. a K+ / O2 exhanger is inhibited by oubain b. a K+ / O2 exhanger is activated by oubain c. a Na+ / O2 exhanger is inhibited by oubain d. approximately 40% of ATP is consumed by the Na+ / K+ ATPase e. oubain blocks O2 uptake 4. Which of these cofactors participates directly in most of the oxidation-reduction reactions in the fermentation of glucose to lactate? a. ADP b. ATP c. FAD/FADH2 d. Glyceraldehyde 3-phosphate e. NAD+/NADH 5. The metabolic function of the pentose phosphate pathway is: a. act as a source of ADP biosynthesis. b. generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids. c. participate in oxidation-reduction reactions during the formation of H2O. d. provide intermediates for the citric acid cycle. e. synthesize phosphorus pentoxide. 7. What is the correct order of function of the following enzymes of β oxidation? 1. β-Hydroxyacyl-CoA dehydrogenase 2. Thiolase 3. Enoyl-CoA hydratase 4. Acyl-CoA dehydrogenase a. 1, 2, 3, 4 b. 3, 1, 4, 2 c. 4, 3, 1, 2 d. 1, 4, 3, 2 e. 4, 2, 3, 1 8. Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as: a. acetoacetyl-CoA. b. acetone. c. beta-hydroxybutyric acid. d. beta-hydroxybutyryl-CoA. e. lactic acid. 9. A hydropathy plot is used to a. determine the water-solubility of a protein. b. deduce the quaternary structure of a membrane protein. c. determine the water content of a native protein. d. extrapolate for the true molecular weight of a membrane protein. e. predict whether a given protein sequence contains membrane-spanning segments. 10. The specificity of the potassium channel for K+ over Na+ is mainly the result of the: a. differential interaction with the selectivity filter protein. b. hydrophobicity of the channel. c. phospholipid composition of the channel. d. presence of carbohydrates in the channel. e. presence of cholesterol in the channel. 11. Which of the following is not involved in the specificity of signal transduction? a. Interactions between receptor and signal molecules b. Location of receptor molecules c. Structure of receptor molecules d. Structure of signal molecules e. Transmembrane transport of signal molecules by receptor molecules 12. Which of the following does not involve cyclic AMP? a. Regulation of glycogen synthesis and breakdown b. Regulation of glycolysis c. Signaling by acetylcholine d. Signaling by epinephrine e.Signalingbyglucagon 14. There is reciprocal regulation of glycolytic and gluconeogenic reactions interconverting fructose-6-phosphate and fructose-1,6-bisphosphate. Which one of the following statements about this regulation is not correct? a. Fructose-2,6-bisphosphate activates phosphofructokinase-1. b. Fructose-2,6-bisphosphate inhibits fructose-1,6-bisphosphatase. c. The fructose-1,6-bisphosphatase reaction is exergonic. d. The phosphofructokinase-1 reaction is endergonic. e. This regulation allows control of the direction of net metabolite flow through the pathway. 15. Which one of the following statements about membranes is true? a. Most plasma membranes contain more than 70% proteins. b. Sterol lipids are common in bacterial plasma membranes. c. Sterol lipids are common in human cell plasma membranes. d. Sterol lipids are common in plant cell plasma membranes. e. The plasma membranes of all cell types within a particular organism have basically the same lipid and protein composition. 16. Membrane proteins: a. are sometimes covalently attached to lipid moieties. b. are sometimes covalently attached to carbohydrate moieties. c. are composed of the same 20 amino acids found in soluble proteins. d. diffuse laterally in the membrane unless they are anchored e. have all of the properties listed above. 17. An integral membrane protein can be extracted with: a. a buffer of alkaline or acid pH. b. a chelating agent that removes divalent cations. c. a solution containing detergent. d. a solution of high ionic strength. e. hot water. 18. Which of these is a general feature of the lipid bilayer in all biological membranes? a. Individual lipid molecules are free to diffuse laterally in the surface of the bilayer. b. Individual lipid molecules in one face (monolayer) of the bilayer readily diffuse (flipflop) to the other monolayer. c. Polar, but uncharged, compounds readily diffuse across the bilayer. d. The bilayer is stabilized by covalent bonds between neighboring phospholipid molecules. e. The polar head groups face inward toward the inside of the bilayer. 19. The fluidity of the lipid side chains in the interior of a bilayer is generally increased by: a. a decrease in temperature. b. an increase in fatty acyl chain length. c. an increase in the number of double bonds in fatty acids. d. an increase in the percentage of phosphatidyl ethanolamine 21. Which of these statements about facilitated diffusion across a membrane is true? a. A specific membrane protein lowers the activation energy for movement of the solute through the membrane. b. It can increase the size of a transmembrane concentration gradient of the diffusing solute. c. It is impeded by the solubility of the transported solute in the nonpolar interior of the lipid bilayer. d. It is responsible for the transport of gases such as O2, N2, and CH4 across biological membranes. e. The rate is not saturable by the transported substrate 22. Glucose transport into erythrocytes is an example of: a. active transport. b. antiport. c. electrogenic uniport d. facilitated diffusion. e. symport. 23. Movement of water across membranes is facilitated by proteins called: a. annexins. b. aquaporins. c. hydropermeases. d. selectins. e. transportins. 24. Scatchard analysis can provide information on: a. enzyme cascades. b. enzyme mechanisms. c. gated ion channels. d. protein phosphorylation. e. receptor-ligand interactions. 25. The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system. a. G protein b. c. d. e. A) B) C) D) ligand-gated receptor-enzyme serpentine receptor voltage-gated 26. Which of the following statements concerning receptor enzymes is correct? They are not usually membrane-associated proteins. They contain an enzyme activity that acts upon a cytosolic substrate. They contain an enzyme activity that acts upon the extracellular ligand. They have a ligand-binding site on the cytosolic side of the membrane. 28. Calmodulin is a(n): A) B) C) D) E) allosteric activator of calcium-dependent enzymes. allosteric inhibitor of calcium-dependent enzymes. calcium-dependent enzyme. cell surface calcium receptor. regulatory subunit of calcium-dependent enzymes. 29. Which one of the following signaling mechanisms is used most predominantly in plants? A) Cyclic-nucleotide dependent protein kinases B) DNA-binding nuclear steroid receptors C) G protein-coupled receptors D) Protein serine/threonine kinases E) Protein tyrosine kinases 30. Steroid hormones are carried on specific carrier proteins because the hormones: a. are too unstable to survive in the blood on their own. b. cannot dissolve readily in the blood because they are too hydrophobic. c. cannot find their target cells without them. d. need them in order to pass through the plasma membrane. e. require subsequent binding to specific receptor proteins in the nucleus. 31. During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue. The most important reaction involved in the reoxidation of NADH is: a. dihydroxyacetone phosphate → glycerol 3-phosphate b. glucose 6-phosphate → fructose 6-phosphate c. isocitrate → α-ketoglutarate d. oxaloacetate → malate e. pyruvate → lactate 32. Which of the following statements is not true concerning glycolysis in anaerobic muscle? a. Fructose 1,6-bisphosphatase is one of the enzymes of the pathway. b. It is an endergonic process. c. It results in net synthesis of ATP. d. It results in synthesis of NADH. e. Its rate is slowed by a high [ATP]/[ADP] ratio. 33. In comparison with the resting state, actively contracting human muscle tissue has a: a. higher concentration of ATP. b. higher rate of lactate formation. c. lower consumption of glucose. d. lower rate of consumption of oxygen e. lower ratio of NADH to NAD+ . 34. Which of the following is a cofactor in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase? a. ATP b. Cu 2+ h 36. Which of the following compounds cannot serve as the starting material for the synthesis of glucose via gluconeogenesis? a. acetate b. glycerol c. lactate d. oxaloacetate e. α-ketoglutarate 37. An enzyme used in both glycolysis and gluconeogenesis is: a. 3-phosphoglycerate kinase. b. glucose 6-phosphatase. c. hexokinase. d. phosphofructokinase-1. e. pyruvate kinase. 38. In humans, gluconeogenesis: a. can result in the conversion of protein into blood glucose. b. helps to reduce blood glucose after a carbohydrate-rich meal. c. is activated by the hormone insulin d. is essential in the conversion of fatty acids to glucose. e. requires the enzyme hexokinase. 39. Which of the following statements about the pentose phosphate pathway is correct? a. It generates 36 mol of ATP per mole of glucose consumed. b. It generates 6 moles of CO2 for each mole of glucose consumed c. It is a reductive pathway; it consumes NADH. d. It is present in plants, but not in animals. e. It provides precursors for the synthesis of nucleotides.