Q&A Hero

Q: The importance of the citric acid cycle in energy production is the formation of significant amounts of A. ATP. B. lactic acid. C. NADH. D. carbon dioxide.

Q: The ATP generated in the citric acid cycle A. is produced directly from the 5th reaction. B. is produced from the reduction of NAD. C. comes from GTP. D. comes from oxidative phosphorylation.

Q: Formation of the maximum number of acetyl CoA molecules from one glucose, produces ______________ molecules of carbon dioxide. A. no B. one C. two D. four

Q: Aerobic respiration A. uses glucose. B. generates water. C. generates oxygen. D. Both uses glucose and generates water.

Q: Acetyl CoA is A. generated from oxaloacetate. B. generated from pyruvic acid. C. generated from citric acid. D. generated from water.

Q: In the complete process of aerobic respiration, the major source of reduced NAD and FAD is glycolysis.

Q: The TCA cycle occurs in mitochondria.

Q: Acetyl CoA and NAD are the end-products of the citric acid cycle.

Q: The citric acid cycle completes the oxidation of glucose started by glycolysis.

Q: One glucose would generate ______________ NADH molecules via the citric acid cycle. A. two B. three C. six D. eight

Q: Each turn of the citric acid cycle directly produces ______________ molecule(s) of ATP. A. one B. two C. four D. no

Q: Each turn of the citric acid cycle produces A. 2 FADH2, 1 ATP, and 3 NADH. B. 1 FADH2, 1 ATP, and 3 NADH. C. 3 FADH2, 2 ATP, and 1 NADH. D. 1 FADH2, 3 ATP, and 2 NADH.

Q: The total amount of FADH2 produced by one turn of the citric acid cycle is A. one molecule. B. two molecules. C. 15 molecules. D. 30 molecules.

Q: Acetyl coenzyme A enables the products of glycolysis to enter the citric acid cycle.

Q: Coenzyme A is derived from the vitamin riboflavin.

Q: In the formation of acetic acid from pyruvic acid, the oxygen in the carbon dioxide comes from oxygen gas.

Q: During the conversion of one pyruvic acid to acetyl coenzyme A, ______________ molecule(s) of carbon dioxide is/are produced. A. no B. one C. two D. four

Q: A deficiency of ______________ would limit production of coenzyme A. A. pantothenic acid B. linoleic acid C. folic acid D. thiamine

Q: A reducing agent A. donates protons to an atom or molecule. B. donates electrons to an atom or molecule. C. accepts protons from an atom or molecule. D. accepts electrons from an atom or molecule. E. Both donates electrons and donates protons are correct.

Q: A common oxidizing agent used to couple chemical reactions in cells is A. riboflavin. B. niacin. C. NADH. D. FAD.

Q: A common reducing agent used to couple chemical reactions in cells is A. riboflavin. B. niacin. C. NADH. D. FAD.

Q: FAD and NAD are coenzymes that act as _______ in biochemical reactions. A. hydrogen carriers B. oxygen carriers C. energy carriers D. vitamin carriers

Q: Consuming extra niacin and riboflavin in the diet will provide extra energy for body functions.

Q: Which of the following cells relies solely on anaerobic metabolism of glucose? A. skeletal muscle cells B. liver cells C. kidney cells D. red blood cells

Q: What percentage of energy released by aerobic respiration of glucose is captured by ATP? A. 25-30% B. 30-34% C. 38-40% D. 42-46%

Q: A molecule that gains a hydrogen is also oxidized.

Q: Reduction and oxidation are always coupled.

Q: NAD is derived from the vitamin A. B-12, cobalamin. B. B-3, niacin. C. B-2, riboflavin. D. B-6, pyridoxine

Q: FAD is derived from vitamin A. B-12. B. B-3, niacin. C. B-2, riboflavin. D. B-6.

Q: Chemically reduced FAD has __________ extra hydrogen atom(s) bound to it. A. one B. two C. three D. no

Q: Oxidized nicotinamide adenine dinucleotide (NAD) has ______________ two hydrogens. lost B. gained C. shared

Q: If NAD becomes reduced it is a(n) A. reducing agent. B. oxidizing agent. C. zymogen. D. allosteric inhibitor.

Q: During oxidation, a molecule or atom A. gains protons. B. loses protons. C. gains electrons. D. loses electrons.

Q: During reduction, a molecule or atom A. gains protons or gains electrons. B. loses protons or gains electrons. C. gains protons or loses electrons. D. loses protons or loses electrons.

Q: A reducing agent donates electrons to a molecule.

Q: Oxidation means that oxygen is part of the reaction.

Q: An atom or molecule that is oxidized is also a reducing agent.

Q: Exergonic reactions proceed with the release of energy.

Q: Free energy is ______________ when exergonic reactions proceed. A. increased B. decreased C. unchanged

Q: Endergonic reactions cause the amount of entropy in the products to be A. increased. B. decreased. C. unchanged.

Q: A ______________ is the amount of heat required to raise the temperature of one cubic centimeter of water one degree on the Celsius scale. A. specific heat B. meter C. boiling point D. calorie

Q: A food calorie (Calorie) is equivalent to which metric measurement of heat? A. calorie B. joule C. kilocalorie D. watt

Q: The reaction of adenosine diphosphate and phosphate generates adenosine triphosphate and energy.

Q: ______________ is the universal energy carrier. A. Glucose B. ATP C. ADP D. GTP

Q: In bioenergetic pathways, as intermediates are acted upon by enzymes, the ultimate result is the release of A. lactate. B. ATP. C. free energy. D. enzymes.

Q: Oxidizing agents accept electrons from molecules undergoing reduction.

Q: Energy transformations increase the entropy of a system is a statement of the A. first law of thermodynamics. B. second law of thermodynamics. C. law of mass action. D. law of conservation of energy.

Q: Energy can change forms, but cannot be created or destroyed is a statement of the A. first law of thermodynamics. B. second law of thermodynamics. C. law of mass action. D. third law of thermodynamics.

Q: Another name for the first law of thermodynamics is the law of conservation of energy.

Q: The greatest increase in entropy occurs A. when starch is degraded to glucose. B. when amylase produces maltose. C. when glucose is converted to galactose. D. when ATP is synthesized.

Q: Metal ions such as magnesium or calcium can serve as enzyme A. coenzymes. B. ribozymes. C. substrates. D. cofactors.

Q: Free energy is the only type that can be used to perform cellular work.

Q: The amount of entropy increases as bonds are broken to generate glucose from glycogen.

Q: Energy transformations result in a(n) ______________ in entropy. increase B. decrease C. no change

Q: Cellular respiration results in a(n) ______________ in entropy as glucose is broken down to form carbon dioxide. increase B. decrease C. no change

Q: The flow of energy in living systems is termed A. entropy. B. enthalpy. C. bioenergetics. D. bioluminescence.

Q: End-product inhibition usually involves allosteric inhibition of an enzyme.

Q: Regulation of a metabolic pathway by the final product of the pathway is termed A. allosteric inhibition. B. end-product inhibition. C. negative feedback. D. Both end-product inhibition and negative feedback are correct.

Q: ______________ occurs when the product of a metabolic pathway binds to an enzyme and decreases enzymatic activity. A. Allosteric inhibition B. End-product therapy C. Second messaging D. Coupling

Q: A defect in the enzyme which converts phenylalanine into tyrosine is characteristic of the disease A. phenylketonuria. B. albinism. C. lactose intolerance. D. maple-syrup disease.

Q: A defect in the enzyme that catalyzes the formation of melanin from DOPA results in A. phenylketonuria. B. albinism. C. lactose intolerance. D. maple-syrup disease.

Q: In response to increased concentration of the final product of a metabolic pathway A. all enzymes in the pathway become more active. B. intermediate enzymes become more active. C. the final product acts as an allosteric regulator of one enzyme in the pathway. D. all enzymes in the pathway become less active.

Q: Decreased phenylalanine metabolism causes A. albinism. B. hypercholeteremia. C. lactose intolerance. D. Tay-Sachs disease.

Q: An inborn error in lipid metabolism may cause all of the following diseases EXCEPT A. Tay-Sachs disease. B. homocystinuria. C. hypercholesteremia. D. Gaucher's disease.

Q: What technique has been affective in the treatment of inborn errors of metabolism such as SCID? A. allosteric inhibition B. gene therapy C. coenzyme activation D. None of the choices is correct.

Q: Enzymes in a metabolic pathway act antagonistically to produce a final product.

Q: Which of the following is NOT true about enzymes? A. As the temperature increases from 25 C to 37 C enzyme activity decreases. B. Very few enzymes require cofactors. C. Most enzymes are not sensitive to changes in pH. D. All are not true.

Q: Which of the following is NOT true of catalysts? A. They are unchanged by the reaction catalyzed. B. They allow endergonic reactions to become exergonic reactions. C. They increase the amount of energy released by a chemical reaction. D. They lower the activation energy of the reaction.

Q: Active enzymes are often called zymogens.

Q: ______________ are inactive forms of digestive enzymes. A. Cofactors B. Coenzymes C. Zymogens D. Both cofactors and zymogens are correct.

Q: At saturation, enzyme activity is maximal.

Q: The principle that reversible reactions will be driven from the side of the equation where the concentration is lower to the side where the concentration is higher is known as the law of mass action.

Q: In the reaction (H2O + CO2 H2CO3), increasing the concentration of H2O would A. decrease the concentration of H2CO3. B. increase the concentration of H2CO3. C. increase the concentration of CO2. D. have no effect on either CO2 or H2CO3 concentrations.

Q: Addition of substrate when enzyme reaction rate is maximal results in A. additional product formation. B. less product formation. C. no change in product formation. D. enzyme destruction.

Q: Most enzymatic reactions in the body are one step processes.

Q: The pH optima for all digestive enzymes are approximately equal to the pH of blood.

Q: An enzyme-catalyzed reaction in the body at 50 C will proceed at a faster rate than at 37 C.

Q: The phosphatase found in bone would have a pH optimum that is ______________ than the pH optimum of the phosphatase found in the prostate gland. A. higher B. lower C. the same as

Q: The enzyme with the lowest pH optimum is A. acid phosphatase. B. lipase. C. monoamine oxidase. D. pepsin.

Q: In an enzymatic reaction, when temperature is increased past the point of "optimal temperature," the enzyme starts to A. increase its catalytic activity. B. reduce its catalytic activity. C. increase its allosteric properties. D. increase product formation.