Biochemistry Exam Questions, Exams of Nursing

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Questions

Place the following reaction intermediates of the CAC in chronological order i. malate ii. fumarate iii. succinyl CoA iv. citrate v. a-ketoglutarate - Correct Answers ✅iv, v, iii, ii, i Oxalosuccinate is a transient intermediate formed during which of the following reactions? - Correct Answers ✅isocitrate to a- ketoglutarate FADH2 is a product of which of the following reactions? - Correct Answers ✅succinate to fumarate NADH is produced in which of the following reactions? - Correct Answers ✅a-ketoglutarate to succinyl CoA Which of the following reactions can be described as anaplerotic? - Correct Answers ✅pyruvate + co2 to oxaloacetate The enzymes that are unique to the glyoxylate cycle include ____________ - Correct Answers ✅isocitrate lyase The regulated enzyme of the CAC include _________ - Correct Answers ✅a-ketoglutarate dehydrogenase

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The enzymes involved in citrate metabolism include all of the following except ________ - Correct Answers ✅malate synthase Redox potential is best defined as - Correct Answers ✅the tendency of a species to gain or lose electrons In order to determine the standard voltage of a reaction - Correct Answers ✅the standard cells must be written as they occur in the reaction and the voltages are added Which of the following reactions is an oxidation reaction? a. NaOH + HCl -> NaCl + H2O b. CH3COOH -> CH3COO- + H+ c. CH3CHO -> CH3CH2OH d. CH3CH2OH -> CH3CHO e. CH2=CH2 + H2O -> CH3CH2OH - Correct Answers ✅CH3CH2OH -> CH3CHO Which of the following reactions has an oxidized product? a. carboxylic acid -> aldehyde b. R-SH + R-SH -> R-S-S-R

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c. alcohol -> ketone d. glutamate -> a-ketoglutarate e. none of the above - Correct Answers ✅none of the above In any redox reaction, an electron donor is - Correct Answers ✅the reducing agent In an redox reaction, an electron acceptor is - Correct Answers ✅converted to an electron donor with the gain of one or more electrons Each turn of the CAC produces how many moles of CO2? - Correct Answers ✅ 2 Acetyl CoA that is consumed by the CAC is produced from which of the following biochemical pathways? a. glycolysis b. fatty acid oxidation c. purine catabolism d. urea cycle e. both A and B are correct - Correct Answers ✅both A and B are correct

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Which of the following is the strongest reducing agent? a. FADH2 (+ 0.22 V) b. H2 (+ 0.424 V) c. cytochrome a * Fe 2+ (-0.29 V) d. lactate (+0.19 V) e. H2O (-0.82 V) - Correct Answers ✅H Which of the following reacts with the acetyl-CoA to form citrate? - Correct Answers ✅oxaloacetate The redox reaction in which succinate is converted to fumarate uses FAD rather than NAD+ because? - Correct Answers ✅FAD is a stronger oxidizing agent than NAD+ Which of the following CAC enzymes are closely regulated? a. citrate synthase b. isocitrate dehydrogenase c. a-ketoglutarate dehydrogenase d. both A and B are correct e. A, B, and C are all correct - Correct Answers ✅A, B, and C are all correct

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Which of the following requires GDP? - Correct Answers ✅succinyl- CoA to succinate How many oxidation steps are there in the CAC? - Correct Answers ✅ 4 Which of the following is a cofactor for the conversion of succinate to fumarate? - Correct Answers ✅FAD Which of the following reactions involves a substrate level phosphorylation? - Correct Answers ✅succinyl-CoA to succinate The carbon skeletons of which of the following can be incorporated directly into the protein? a. malate b. succinate c. a-ketoglutarate d. oxaloacetate e. both C and D are correct - Correct Answers ✅both C and D are correct Which of the following is a positive effector of isocitrate dehydrogenase? - Correct Answers ✅ADP

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Which of the following is not directly required for the activity of pyruvate dehydrogenase? - Correct Answers ✅ATP The overall reaction catalyzed by pyruvate dehydrogenase is which of the following? a. CH3COCHO + NAD+ + CoASH -> CH3CHOSCoA + NADH b. CH3COCOO- + FAD + CoASH -> CH3COSCoA + FADH c. CH3COCOO- + NAD+ + CoASH -> CH3COSCoA + NADH d. CH3CH(OH)COO- + NADH + CoASH -> CH3CH(OH)COSCoA + NAD+ e. None of the above are correct ...what kind of fresh hell is this - Correct Answers ✅c. CH3COCOO- + NAD+ + CoASH -> CH3COSCoA + NADH The CAC is a component of metabolic respiration, i.e, molecular oxygen is... - Correct Answers ✅only indirectly involved in the reactions of the cycle The reaction process catalyzed by pyruvate dehydrogenase requires all of the following except ______ - Correct Answers ✅FMN All of the following are components of the electron transport chain except ____________ - Correct Answers ✅Coenzyme A

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The ETC component that transfers electrons directly to oxygen is _________ - Correct Answers ✅cytochrome oxidase During the oxidation of NADH there are several steps in which DEo' is sufficient for ATP synthesis. These occur with in complexes... - Correct Answers ✅I, III, and IV Which of the following molecules inhibits Complex I of the electron transport chain? - Correct Answers ✅Amytal ATP synthesis and mitochondrial electron transport are coupled by a. protonmotive force b. high energy intermediates c. proton gradient d. Both A and C are correct e. A, B, and C are correct - Correct Answers ✅d. Both A and C are correct Evidence supporting the chemiosmotic theory includes all of the following except - Correct Answers ✅the pH of a weakly buffered suspension of mitochondria rises when O2 is added

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Examples of uncouplers include (there are 2) - Correct Answers ✅DNP and gramicidin In the ATP Synthase the F0 factor a. has 3 types of subunits b. possesses the ATPase activity c. is a transmembrane proton channel d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅e. Both A and C are correct The maximum P/O ratio for FADH2 is ____________ - Correct Answers ✅1. The control of aerobic respiration by ______________________________ is referred to as respiratory control - Correct Answers ✅ADP The first ROS formed during the reduction of oxygen is ______________ - Correct Answers ✅superoxide radical The reaction of Fe2+ with H2O2 results in the production of a. hydroxyl radical

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b. hydroxide ion c. superoxide radical d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅d. Both A and B are correct ROS are generated during a. xenobiotic metabolism b. respiratory burst c. ionizing radiation d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅e. A, B, and C are correct Glutathione peroxidase a. converts organic peroxides into alcohols b. generates GSH from GSSG c. reduces H2O2 to H2O d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅e. Both A and C are correct

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The NADPH required for the regeneration of GSH from GSSG is synthesized by the reactions of - Correct Answers ✅the pentose phosphate pathway Glutathione peroxidase requires _____________ for full activity - Correct Answers ✅selenium Examples of antioxidants include all of the following except a. ascorbic acid b. b-Carotene c. a-Tocopherol d. phenol e. gramicidin - Correct Answers ✅e. gramicidin One of the mechanisms by which vitamin C protects membrane is by a. regenerating reduced a-tocopherol b. reacting with proline c. reacting with peroxyl radicals d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅e. Both A and C are correct

Questions

The ultimate electron acceptor of the mitochondrial electron transport system is - Correct Answers ✅O In complex I of the ETC, the major sources of NADH include a. fatty acid oxidation b. CoQ c. NADPH d. the citric acid cycle e. Both A and D are correct - Correct Answers ✅e. Both A and D are correct In complex III, electrons are transferred from UQH2 to - Correct Answers ✅cytochrome c _______ is a metal cofactor of the cytochromes - Correct Answers ✅Fe Carbon monoxide inhibits which of the following? - Correct Answers ✅cytochrome oxidase Which of the following is the best reducing agent? a. H2O

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b. O c. FADH d. FMNH e. NADH - Correct Answers ✅e. NADH The final product of oxidative phosphorylation is? - Correct Answers ✅ATP ________________ are hydrophobic molecules that dissipate ion gradients - Correct Answers ✅ionophores The return of _______ into the mitochondrion is coupled to the formation of _______ - Correct Answers ✅H+; ATP The energy that is captured by the electron transport system and used in oxidative phosphorylation is in the form of a. NADH b. FADH c. ATP d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅d. Both A and B are correct

Questions

Reducing power generated in the cytoplasm can be transferred into the mitochondrion by which of the following processes? a. glycerol phosphate shuttle b.malate-aspartate shuttle c. the phosphate shuttle d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅d. Both A and B are correct Fatty acid groups are referred to as ________ groups. - Correct Answers ✅acyl The double bonds in naturally occurring fatty acids are usually ______ isomers - Correct Answers ✅cis The essential fatty acids are a. arachidonic acid b. linoleic acid c. linolenic acid d. Both A and B are correct e. Both B and C are correct

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what the **** lmao - Correct Answers ✅e. Both B and C are correct Fatty acids react with alcohols to form? - Correct Answers ✅esters Prostaglandins are involved in? a. ovulation b. inflammation c. digestion d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅d. Both A and B are correct The functions of fat include: a. insulation b. energy storage c. water-repellent properties d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅e. A, B, and C are correct Waxes

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a. are complex mixtures of nonpolar lipids b. are esters formed from long-chain fatty acids and long-chain alcohols c. contain hydrocarbons, sterols, and alcohols d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅e. Both A and C are correct Phospholipids are a. structural components of membranes b. surface active agents c. rich energy sources d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅d. Both A and B are correct Phosphatidylcholine is sometimes referred to as a. PIP b. cephalin c. ceramide d. cardiolipin e. none of the above - Correct Answers ✅e. none of the above

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The myelin sheath a. surrounds nerve cell axons b. contains large amounts of cardiolipin c. facilitates nerve impulse transmission d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅e. Both A and C are correct All of the following are glycolipids except ____________ a. sulfatides c. cerebrosides c. gangliosides d. Both A and B are correct e. none of the above - Correct Answers ✅e. none of the above The role of very low density lipoproteins is a. scavenging the cholesterol from cell membranes b. transporting of lipids from liver to tissue c. transporting of cholesterol from esters to the liver d. Both A and B are correct

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e. A, B, and C are correct - Correct Answers ✅b. transporting of lipids from liver to tissue Which of the following statements concerning carotenoids is not true? a. carotenoids are the only examples of the monoterpenes b. the carotenes are hydrocarbon members of the carotenoids c. xanthophylls are oxygenated derivatives of the carotenes d. carotenes are orange-colored pigments e. none of the above - Correct Answers ✅a. carotenoids are the only examples of the monoterpenes Which of the following statements concerning coronary artery disease is not true? a. coronary artery disease is one of the most common consequences of atherosclerosis b. high plasma LDL levels are correlated with high risk for coronary artery disease c. cells destined to become "foam cells" in the lining of the blood vessels possesses LDL receptors d. the macrophages found within atherosclerotic plaque possesses LDL receptors with an affinity for oxidized LDL e. none of the above - Correct Answers ✅e. none of the above

Questions

The basic structure of biological membranes is a consequence of _____________ - Correct Answers ✅phospholipids A membrane's fluidity is largely determined by the percentage of - Correct Answers ✅unsaturated fatty acids In the fluid mosaic model of membrane structure - Correct Answers ✅proteins float in a lipid bilayer Which of the following statements concerning anion channel proteins is not true? a. it plays an important role in CO2 transport in blood b. it facilitates the chloride shift c. HCO3- and Cl- exchange occurs through the anion channel protein d. the N-terminal methionine residue of the anion channel protein is prenylated e. none of the above - Correct Answers ✅d. the N-terminal methionine residue of the anion channel protein is prenylated Energy-requiring transport mechanisms include? - Correct Answers ✅primary active transport

Questions

In simple diffusion a solute... - Correct Answers ✅is propelled by random molecular motion Which of the following statements is not true? a. membrane potential is an electrical gradient across a membrane b. a decrease in membrane potential is referred to as membrane depolarization c. the term repolarization is defined as the reestablishment of the original membrane potential d.the diffusion of K+ ions out of a nerve cell makers the inside of the membrane less negative e. the Na+ channel in muscle and nerve cells is a voltage-gated channel

• Correct Answers ✅d. the diffusion of K+ ions out of a nerve cell makes the inside of the membrane less negative In muscle cells, local depolarization caused by acetylcholine binding leads to the opening of the voltage-gated _____channels. a. Cl- b. K+ c. H+ d. Na+ e. glucose permease - Correct Answers ✅d. Na+

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The function of glucose permease is an example of - Correct Answers ✅secondary active transport The glucose permease is an example of a/an ______________ - Correct Answers ✅symporter Membrane receptors are transmembrane molecules or molecular complexes that.. a. monitor and respond to changes in the cell's environment b. bind to hormones or neurotransmitters c. are involved in embryonic and fetal development d. initiate an intracellular response when they bind an appropriate muscle e. all of the above - Correct Answers ✅e. al of the above Patients with familial hypercholesterolemia - Correct Answers ✅develop xanthomas _______________ is a technique used to investigate lateral diffusion of membrane components - Correct Answers ✅fluorescence recovery after photobleaching Bacterorhodopsin of the purple membrane of Halobacterium...

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a. acts as a light-driven Cl- channel b. is the sole protein component of purple membrane c. is formed under conditions of low O2 concentration and high lit intensity d. Both A and B are correct e. Both B and C are correct - Correct Answers ✅e. Both B and C are correct Rbc membrane is useful in membrane research because it is a. obtainable in large amounts from blood banks b. easily purified c. easily separated from intracellular membrane d. Both A and B are correct e. A, B, and C are correct - Correct Answers ✅d. Both A and B are correct Nephrogenic diabetes insipidis is... a. a rare genetic disease b. caused by a mutated water channel c. a malady in which affected individuals produce excessively concentrated urine d. Both A and B are correct

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e. A, B, and C are correct - Correct Answers ✅e. A, B, and C are correct In plants triacylglycerols are stored in ___________ - Correct Answers ✅oil bodies _____________ is used to transport fatty acids into the mitochondria - Correct Answers ✅carnitine The b-oxidation of fatty acids requires...? a. coenzyme A b. FAD c. NAD+ d. Both A and C are correct e. A, B, and C are correct - Correct Answers ✅e. A, B, and C are correct _____________, a product of the oxidation of odd-chain fatty acids, is converted to succinyl-CoA - Correct Answers ✅propionyl-CoA ________________ derive a substantial amount of energy from the oxidation of odd-chain fatty acids - Correct Answers ✅ruminants

Questions

The carbon atoms of cholesterol are derived from? - Correct Answers ✅acetyl CoA In animals the function of peroxisomal b-oxidation appears to be to - Correct Answers ✅shorten very long chain fatty acids The acetyl-CoA derived from gylyoxysomal b-oxidation is converted to carbohydrate via a. the glyoxylate cycle b. the citric acid cycle c. gluconeogensis d. Both A and B are correct e. Both A and C are correct - Correct Answers ✅e. Both A and C are correct Refsum's disease results from a buildup of ________ in nerve tissue - Correct Answers ✅phytanic acids Which of the following is not one of the ketone bodies? a. acetoacetate b. b-Hydroxybutyrate c. b-Methylgiutarate

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d. acetone e. none of the above - Correct Answers ✅c. b-Methylgiutarate Most eicosanoids are derived from ________ acid. - Correct Answers ✅arachidonic Prostaglandin synthesis is initiated when cyclooxygenase converts arachidonic acid into ___________ - Correct Answers ✅PGG2 The intermediates in fatty acid synthesis are linked through a ___________ linkage to ACP - Correct Answers ✅thioester Saturated fatty acids containing up to 16 carbon atoms are assembled in the ________ - Correct Answers ✅cytoplasm Fatty acid synthesis begins with the carboxylation of acetyl CoA to form ____________ - Correct Answers ✅malonyl-CoA All of the following are enzymatic activities found in fatty acid synthase except? a. b-ketoacyl-ACP reductase b. acetyl transacylase c. thioesterase

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d. lipoxygenase e. b-hydroxyacyl-ACP dehydrase - Correct Answers ✅d. lipoxygenase Desaturation of fatty acids involves all of the following except: a. O2 b. NADH c. cytochrome b5 d. cytochrome b5 reductase e. none of the above - Correct Answers ✅e. none of the above Plant fatty acid synthesis occurs in _________ - Correct Answers ✅chloroplasts The conversion of acyl-CoA to malonyl-CoA is inhibited by __________ a. glucagon b. epinephrin c. palmitoyl-CoA d. All of the above are correct e. none of the above - Correct Answers ✅d. All of the above are correct