front 1 Use the following information to answer the question below. | back 1 C |
front 2 Use the following information to answer the question below. | back 2 B |
front 3 Use the following information to answer the question below. | back 3 D |
front 4 Use the following information to answer the question below. | back 4 exergonic, ∆G < 0 |
front 5 Use the following information to answer the question below. | back 5 curves 1 and 4 |
front 6 Use the following information to answer the question below. | back 6 curves 3 and 5 |
front 7 Use the following information to answer the question below. | back 7 Most enzyme molecules are occupied by substrate at high reactant concentrations. |
front 8 Rate of an enzyme-catalyzed reaction as a function of varying
reactant concentration, with the concentration of enzyme constant. | back 8 doubling the enzyme concentration |
front 9 How might a change of one amino acid at a site, distant from the active site of an enzyme, alter the substrate specificity of an enzyme? | back 9 by changing the three-dimensional conformation of the enzyme |
front 10 Which of the following graphs most likely describes the effect of pH on the function of the enzyme catalase in human cells? Note: The x-axis is pH and the y-axis is enzyme activity. | back 10 bell graph |
front 11 How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction? | back 11 by binding to an allosteric site, thus changing the shape of the active site of the enzyme |
front 12 Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as ________. | back 12 a cofactor necessary for enzyme activity |
front 13 Which of the following conditions may be overcome by increasing the substrate concentration in an enzymatic reaction with a fixed amount of enzyme? | back 13 competitive inhibition |
front 14 Which of the following statements describes a key component of the induced fit hypothesis of enzyme catalysis? | back 14 Binding of substrate to the active site changes the shape of the active site of an enzyme. |
front 15 Which of the following is a primary function of the active site of an enzyme? | back 15 It catalyzes the reaction associated with the enzyme. |
front 16 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? | back 16 -20 kcal/mol |
front 17 What is the name of the thermodynamic barrier that must be overcome before products are formed in a spontaneous reaction? | back 17 activation energy |
front 18 Which of the following characteristics is most likely to be associated with an enzyme that catalyzes two different chemical reactions? | back 18 Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures. |
front 19 Which of the following aspects of enzyme structure is best described by a clasping handshake analogy? | back 19 the specific manner in which an enzyme binds substrate |
front 20 Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst? | back 20 The catalyzed reaction will have the same ∆G. |
front 21 Which of the following statements about enzyme function is true? | back 21 Enzymes increase the rate of chemical reactions by lowering activation energy barriers. |
front 22 How do cells use the ATP cycle illustrated in the figure? | back 22 Cells use the cycle to recycle ADP and phosphate. |
front 23 Which of the following is the most correct interpretation of the figure? | back 23 ATP is a molecule that acts as an intermediary to store energy for cellular work. |
front 24 A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases, although they do not 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? | back 24 ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. |
front 25 When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell? | back 25 It may be used to form a phosphorylated intermediate. |
front 26 When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? | back 26 It is lost to the environment. |
front 27 Which of the following statements describes a common characteristic of catabolic pathways? | back 27 They are exergonic and provide energy that can be used to produce ATP from ADP and i. |
front 28 Which of the following molecules is most similar in structure to ATP? | back 28 an RNA nucleotide |
front 29 Why is the ΔG of ATP hydrolysis in the cell about twice as great as the ΔG of ATP hydrolysis in a test tube under standard conditions? | back 29 Reactant and product concentrations in the test tube are different from those in the cell. |
front 30 Which of the following statements describes a central role that ATP plays in cellular metabolism? | back 30 ATP provides energy coupling between exergonic and endergonic reactions. |
front 31 Why do hydrolysis reactions occur more readily in solution than dehydration reactions? | back 31 Hydrolysis reactions are exergonic and increase entropy of the system. |
front 32 The relationship between catabolism and anabolism is most similar to the relationship between which of the following pairs of terms? | back 32 exergonic; endergonic |
front 33 Chemical equilibrium is relatively rare in living cells because metabolic pathways are interconnected. Which of the following statements describes an example of a reaction that may be at chemical equilibrium in a cell? | back 33 a chemical reaction in which neither the reactants nor the products are being produced or consumed in any metabolic pathway at that time in the cell |
front 34 A chemical reaction that has a positive ΔG is best described as ________. | back 34 endergonic |
front 35 Which of the following statements is true for all exergonic reactions? | back 35 The reaction proceeds with a net release of free energy. |
front 36 Which of the following statements is true for a system at chemical equilibrium? | back 36 The system can do no work. |
front 37 The mathematical expression for the change in free energy of a system is ΔG = ΔH - TΔS. Which of the following statements is correct? | back 37 ΔG is the change in free energy. |
front 38 Which of the following statements about the evolution of life on Earth, from simple prokaryote-like cells to multicellular eukaryotic organisms, is true? | back 38 It has occurred in accordance with the laws of thermodynamics and resulted in a substantial decrease in the entropy of the planet. |
front 39 Which of the following types of reactions would decrease the entropy within a cell? | back 39 anabolic reactions |
front 40 Which of the following statements is consistent with the second law of thermodynamics? | back 40 A constant input of energy is required to maintain the high level of cellular organization. |
front 41 Which of the following statements is a logical consequence of the second law of thermodynamics? | back 41 Each chemical reaction in an organism must increase the total entropy of the universe. |
front 42 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? | back 42 The decrease in entropy is associated with growth of an organism. As a consequence of growth, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their increased complexity. |
front 43 Which of the following statements is an important consequence of the first law of thermodynamics for a living organism? | back 43 An organism ultimately must obtain all of the necessary energy for life from its environment. |
front 44 Which of the following statements describes the first law of thermodynamics? | back 44 Energy cannot be created or destroyed. |
front 45 Which of the following statements about anabolic pathways is true? | back 45 They consume energy to build up polymers from monomers. |
front 46 Which of the following terms most precisely describes the cellular process of breaking down large molecules into smaller ones? | back 46 catabolism (catabolic pathways) |
front 47 A decrease in entropy is associated with which type of reaction? | back 47 dehydration |
front 48 Most cells cannot harness heat to perform work because ________. | back 48 temperature is usually uniform throughout a cell |
front 49 Which of the following is an example of potential rather than kinetic energy? | back 49 a molecule of glucose |
front 50 Which of the following statements is true of metabolism in its entirety in all organisms? | back 50 Metabolism consists of all the energy transformation reactions in an organism. |