Campbell Biology 2nd Canadian Edition Plus Mastering Biology By Jane B. Reece – Test Bank

Campbell Biology 2nd Canadian Edition Plus Mastering Biology By Jane B. Reece – Test Bank

Campbell Biology, Cdn. Ed., 2e (Reece et al.)

Chapter 8 An Introduction to Metabolism

1) Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? A) catalysis B) metabolism C) anabolism D) dehydration E) catabolism Answer: E Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 2) Which of the following is (are) true for anabolic pathways? A) They do not depend on enzymes. B) They are usually highly spontaneous chemical reactions. C) They consume energy to build up polymers from monomers. D) They release energy as they degrade polymers to monomers. E) They consume energy to decrease the entropy of the organism and its environment. Answer: C Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 3) Which of the following is a statement of the first law of thermodynamics? A) Energy cannot be created or destroyed. B) The entropy of the universe is decreasing. C) The entropy of the universe is constant. D) Kinetic energy is stored energy that results from the specific arrangement of matter. E) Energy cannot be transferred or transformed. Answer: A Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 4) For living organisms, which of the following is an important consequence of the first law of thermodynamics? A) The energy content of an organism is constant. B) The organism ultimately must obtain all of the necessary energy for life from its environment. C) The entropy of an organism decreases with time as the organism grows in complexity. D) Organisms grow by converting energy into organic matter. E) Life does not obey the first law of thermodynamics. Answer: B Type: MC Topic: Concept 8.1 Skill: Synthesis/Evaluation 5) Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics? A) Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time. B) Life obeys the second law of thermodynamics because the decrease in entropy as the organism grows is exactly balanced by an increase in the entropy of the universe. C) Living organisms do not follow the laws of thermodynamics. D) As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth. E) Living organisms are able to transform energy into entropy. Answer: D Type: MC Topic: Concept 8.1 Skill: Synthesis/Evaluation 6) Whenever energy is transformed, there is always an increase in the A) free energy of the system. B) free energy of the universe. C) entropy of the system. D) entropy of the universe. E) enthalpy of the universe. Answer: D Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 7) Which of the following statements is a logical consequence of the second law of thermodynamics? A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe. B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe. C) Every energy transfer requires activation energy from the environment. D) Every chemical reaction must increase the total entropy of the universe. E) Energy can be transferred or transformed, but it cannot be created or destroyed. Answer: D Type: MC Topic: Concept 8.1 Skill: Synthesis/Evaluation 8) Which of the following statements is representative of the second law of thermodynamics? A) Conversion of energy from one form to another is always accompanied by some gain of free energy. B) Heat represents a form of energy that can be used by most organisms to do work. C) Without an input of energy, organisms would tend toward decreasing entropy. D) Cells require a constant input of energy to maintain their high level of organization. E) Every energy transformation by a cell decreases the entropy of the universe. Answer: D Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 9) Which of the following types of reactions would decrease the entropy within a cell? A) anabolic reactions B) hydrolysis C) respiration D) digestion E) catabolic reactions Answer: A Type: MC Topic: Concept 8.1 Skill: Application/Analysis 10) Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellular eukaryotic organisms A) has occurred in accordance with the laws of thermodynamics. B) has caused an increase in the entropy of the planet. C) has been made possible by expending Earth’s energy resources. D) has occurred in accordance with the laws of thermodynamics, by expending Earth’s energy resources and causing an increase in the entropy of the planet. E) violates the laws of thermodynamics because Earth is a closed system. Answer: A Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 11) Which of the following is an example of potential rather than kinetic energy? A) the muscle contractions of a person mowing grass B) water rushing over Niagara Falls C) light flashes emitted by a firefly D) a molecule of glucose E) the flight of an insect foraging for food Answer: D Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 12) Which of the following is the smallest closed system? A) a cell B) an organism C) an ecosystem D) Earth E) the universe Answer: E Type: MC Topic: Concept 8.1 Skill: Knowledge/Comprehension 13) Which of the following is true of metabolism in its entirety in all organisms? A) Metabolism depends on a constant supply of energy from food. B) Metabolism depends on an organism’s adequate hydration. C) Metabolism uses all of an organism’s resources. D) Metabolism consists of all the energy transformation reactions in an organism. E) Metabolism manages the increase of entropy in an organism. Answer: D Type: MC Topic: Concepts 8.1, 8.5 Skill: Synthesis/Evaluation 14) The mathematical expression for the change in free energy of a system is ΔG = ΔH – TΔS. Which of the following is (are) correct? A) ΔS is the change in enthalpy, a measure of randomness. B) ΔH is the change in entropy, the energy available to do work. C) ΔG is the change in free energy. D) T is the temperature in degrees Celsius. E) T is the temperature in degrees Fahrenheit. Answer: C Type: MC Topic: Concept 8.2 Skill: Knowledge/Comprehension 15) A system at chemical equilibrium A) consumes energy at a steady rate. B) releases energy at a steady rate. C) consumes or releases energy, depending on whether it is exergonic or endergonic. D) has zero kinetic energy. E) can do no work. Answer: E Type: MC Topic: Concept 8.2 Skill: Knowledge/Comprehension 16) Which of the following is true for all exergonic reactions? A) The products have more total energy than the reactants. B) The reaction proceeds with a net release of free energy. C) The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants. D) A net input of energy from the surroundings is required for the reactions to proceed. E) The reactions are rapid. Answer: B Type: MC Topic: Concept 8.2 Skill: Knowledge/Comprehension 17) Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell? A) a reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium B) a chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell’s surroundings C) an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment D) a chemical reaction in which both the reactants and products are not being produced or used in any active metabolic pathway E) no possibility of having chemical equilibrium in any living cell Answer: D Type: MC Topic: Concept 8.2 Skill: Synthesis/Evaluation 18) Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? A) +ΔH, +ΔS, +ΔG B) +ΔH, -ΔS, -ΔG C) +ΔH, -ΔS, +ΔG D) -ΔH, -ΔS, +ΔG E) -ΔH, +ΔS, +ΔG Answer: C Type: MC Topic: Concept 8.2 Skill: Application/Analysis 19) When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the changes in free energy, total energy, and entropy are as follows A) +ΔG, +ΔH, +ΔS. B) +ΔG, +ΔH, -ΔS. C) +ΔG, -ΔH, -ΔS. D) -ΔG, +ΔH, +ΔS. E) -ΔG, -ΔH, -ΔS. Answer: B Type: MC Topic: Concept 8.2 Skill: Application/Analysis 20) A chemical reaction that has a positive ΔG is correctly described as A) endergonic. B) endothermic. C) enthalpic. D) spontaneous. E) exothermic. Answer: A Type: MC Topic: Concept 8.2 Skill: Knowledge/Comprehension 21) Which of the following best describes enthalpy (H)? A) the total kinetic energy of a system B) the heat content of a chemical system C) the system’s entropy D) the cell’s energy equilibrium E) the condition of a cell that is not able to react Answer: B Type: MC Topic: Concept 8.2 Skill: Knowledge/Comprehension 22) For the hydrolysis of ATP to ADP + i, the free energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the free energy change is about -13 kcal/mol. What can we conclude about the free energy change for the formation of ATP from ADP and i under cellular conditions? A) It is +7.3 kcal/mol. B) It is less than +7.3 kcal/mol. C) It is about +13 kcal/mol. D) It is greater than +13 kcal/mol. E) The information given is insufficient to deduce the free energy change. Answer: C Type: MC Topic: Concepts 8.2, 8.3 Skill: Application/Analysis 23) Why is ATP an important molecule in metabolism? A) Its hydrolysis provides an input of free energy for exergonic reactions. B) It provides energy coupling between exergonic and endergonic reactions. C) Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy. D) Its terminal phosphate bond has higher energy than the other two. E) It is one of the four building blocks for DNA synthesis. Answer: B Type: MC Topic: Concept 8.3 Skill: Knowledge/Comprehension 24) When 10 000 molecules of ATP are hydrolyzed to ADP and i in a test tube, about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation? A) Living systems harness the energy released to perform work. B) Cells are less efficient at heat production than nonliving systems. C) The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. D) The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. E) Reactant and product concentrations in the test tube are different from those in the cell. Answer: A Type: MC Topic: Concept 8.3 Skill: Application/Analysis 25) Which of the following is most similar in structure to ATP? A) a pentose sugar B) a DNA nucleotide C) an RNA nucleotide D) an amino acid with three phosphate groups attached E) a phospholipid Answer: C Type: MC Topic: Concept 8.3 Skill: Knowledge/Comprehension 26) Which of the following statements is true concerning catabolic pathways? A) They combine molecules into more energy-rich molecules. B) They supply energy, primarily in the form of ATP, for the cell’s work. C) They are endergonic. D) They are spontaneous and do not need enzyme catalysis. E) They build up complex molecules such as protein from simpler compounds. Answer: B Type: MC Topic: Concept 8.3 Skill: Knowledge/Comprehension 27) When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? A) It is used to power yet more cellular work. B) It is used to store energy as more ATP. C) It is used to generate ADP from nucleotide precursors. D) It is lost to the environment. E) It is transported to specific organs such as the brain. Answer: D Type: MC Topic: Concept 8.3 Skill: Knowledge/Comprehension 28) When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell? A) The phosphate is released as an excretory waste. B) The phosphate can only be used to regenerate more ATP. C) The phosphate can be added to water and excreted as a liquid. D) The phosphate may be incorporated into any molecule that contains phosphate. E) It enters the nucleus to affect gene expression. Answer: D Type: MC Topic: Concept 8.3 Skill: Application/Analysis 29) A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases although they don’t often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell’s cytosol has a free calcium ion concentration of 10-7 while the concentration in the SR is 10-2, then how is the ATPase acting? A) ATPase activity must be powering an inflow of calcium from the outside of the cell into the SR. B) ATPase activity must be transferring i to the SR to enable this to occur. C) ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. D) ATPase activity must be opening a channel for the calcium ions to diffuse back into the SR along the concentration gradient. E) ATPase activity must be routing calcium ions from the SR to the cytosol, and then to the cell’s environment. Answer: C Type: MC Topic: Concept 8.3 Skill: Synthesis/Evaluation 30) What is the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in RNA? A) The sugar molecule is different. B) The nitrogen-containing base is different. C) The number of phosphates is three instead of one. D) The number of phosphates is three instead of two. E) There is no difference. Answer: E Type: MC Topic: Concept 8.3 Skill: Knowledge/Comprehension 31) Which of the following statements is true about enzyme-catalyzed reactions? A) The reaction is faster than the same reaction in the absence of the enzyme. B) The free energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme. C) The reaction always goes in the direction toward chemical equilibrium. D) Enzyme-catalyzed reactions require energy to activate the enzyme. E) Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions. Answer: A Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 32) Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction’s A) entropy. B) activation energy. C) endothermic level. D) equilibrium point. E) free-energy content. Answer: B Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 33) A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because A) the starch solution has less free energy than the sugar solution. B) the hydrolysis of starch to sugar is endergonic. C) the activation energy barrier for this reaction cannot be surmounted. D) starch cannot be hydrolyzed in the presence of so much water. E) starch hydrolysis is nonspontaneous. Answer: C Type: MC Topic: Concept 8.4 Skill: Application/Analysis 34) Which of the following statements regarding enzymes is true? A) Enzymes increase the rate of a reaction by making the reaction more exergonic. B) Enzymes increase the rate of a reaction by lowering the activation energy barrier. C) Enzymes increase the rate of a reaction by reducing the rate of reverse reactions. D) Enzymes change the equilibrium point of the reactions they catalyze. E) Enzymes make the rate of a reaction independent of substrate concentrations. Answer: B Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 35) During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction? A) -40 kcal/mol B) -20 kcal/mol C) 0 kcal/mol D) +20 kcal/mol E) +40 kcal/mol Answer: B Type: MC Topic: Concept 8.4 Skill: Application/Analysis 36) The active site of an enzyme is the region that A) binds allosteric regulators of the enzyme. B) is involved in the catalytic reaction of the enzyme. C) binds noncompetitive inhibitors of the enzyme. D) is inhibited by the presence of a coenzyme or a cofactor. Answer: B Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 37) According to the induced-fit hypothesis of enzyme catalysis, which of the following is correct? A) The binding of the substrate depends on the shape of the active site. B) Some enzymes change their structure when activators bind to the enzyme. C) A competitive inhibitor can outcompete the substrate for the active site. D) The binding of the substrate changes the shape of the enzyme’s active site. E) The active site creates a microenvironment ideal for the reaction. Answer: D Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 38) Mutations that result in single amino acid substitutions in an enzyme A) may have no effect on the activity or properties of the enzyme. B) will almost always destroy the activity of the enzyme. C) will often cause a change in the substrate specificity of the enzyme. D) may change the ∆G of the reaction. E) may, in rare cases, cause the enzyme to run reactions in reverse. Answer: A Type: MC Topic: Concept 8.4 Skill: Synthesis/Evaluation 39) Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? A) denaturization of the enzyme B) allosteric inhibition C) competitive inhibition D) saturation of the enzyme activity E) insufficient cofactors Answer: C Type: MC Topic: Concept 8.4 Skill: Application/Analysis 40) Which of the following is true of enzymes? A) Nonprotein cofactors alter the substrate specificity of enzymes. B) Enzyme function is increased if the 3-D structure or conformation of an enzyme is altered. C) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. D) Enzymes increase the rate of chemical reaction by lowering activation energy barriers. E) Enzymes increase the rate of chemical reaction by providing activation energy to the substrate. Answer: D Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 41) Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n) A) competitive inhibitor of the enzyme. B) noncompetitive inhibitor of the enzyme. C) allosteric activator of the enzyme. D) cofactor necessary for enzyme activity. E) coenzyme derived from a vitamin. Answer: D Type: MC Topic: Concept 8.4 Skill: Application/Analysis 42) Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst? A) The catalyzed reaction will be slower. B) The catalyzed reaction will have a different ∆G. C) The catalyzed reaction will have higher activation energy. D) The catalyzed reaction will consume all of the catalyst. E) The catalyzed reaction will have a lower activation energy. Answer: E Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension 43) Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make it resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses? A) in or near the active site B) at an allosteric site C) at a cofactor binding site D) in regions of the protein that determine packaging into the virus capsid E) Such mutations could occur anywhere with equal probability. Answer: A Type: MC Topic: Concept 8.4 Skill: Application/Analysis 44) Protein kinases are enzymes that transfer the terminal phosphate from ATP to an amino acid residue on the target protein. Many are located in/on the plasma membrane as integral membrane proteins or peripheral membrane proteins. What purpose may be served by their plasma membrane localization? A) Membrane localization allows for unique protein folding of the protein kinases. B) Protein kinases can more readily encounter and phosphorylate other membrane proteins. C) Membrane localization lowers the activation energy of the phosphorylation reaction. D) Protein kinases flip back and forth across the membrane to access target proteins on either side. E) Protein kinases require phospholipids as a cofactor. Answer: B Type: MC Topic: Concept 8.4 Skill: Application/Analysis 45) Although unlikely, if your fever exceeded 41◦C what might be a consequence? A) destruction of your enzymes’ primary structure B) removal of amine groups from your proteins C) change in the tertiary structure of your enzymes D) removal of the amino acids in active sites of your enzymes E) binding of your enzymes to inappropriate substrates Answer: C Type: MC Topic: Concept 8.4 Skill: Application/Analysis 46) How does a noncompetitive inhibitor decrease the rate of an enzyme reaction? A) by binding at the active site of the enzyme B) by changing the shape of the enzyme’s active site C) by changing the free energy change of the reaction D) by acting as a coenzyme for the reaction E) by decreasing the activation energy of the reaction Answer: B Type: MC Topic: Concept 8.4 Skill: Knowledge/Comprehension