front 1 Which of the following statements regarding enzymes is true? | back 1 Enzymes increase the rate of a reaction |
front 2 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following would be the same in an enzyme-catalyzed or noncatalyzed reaction? | back 2 d |
front 3 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following represents the activation energy required for a noncatalyzed reaction? | back 3 c |
front 4 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following represents the activation energy required for the enzyme-catalyzed reaction? | back 4 b |
front 5 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following bests describes the reaction? | back 5 negative ΔG, spontaneous |
front 6 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? | back 6 +ΔH, -ΔS, +ΔG |
front 7 Why is ATP an important molecule in metabolism? | back 7 It provides energy coupling between exergonic and endergonic reactions |
front 8 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following represents the ΔG of the reaction? | back 8 d |
front 9 Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity? | back 9 compartmentalization of enzymes into defined organelles |
front 10 When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? | back 10 It is lost to the environment |
front 11 Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? | back 11 competitive inhibition |
front 12 Some enzymatic regulation is allosteric. In such cases, which of the following would usually be found? | back 12 an enzyme with more than one subunit |
front 13 The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as | back 13 feedback inhibition |
front 14 Which of the following is most similar in structure to ATP? | back 14 an RNA nucleotide |
front 15 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Assume that the reaction has a ΔG of -5.6 kcal/mol. Which of the following would be true? | back 15 The reaction would result in an increase in entropy (S) and a decrease in the total energy content (H) of the system |
front 16 When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell? | back 16 It can be added to other molecules in order to activate them |
front 17 Which of the following metabolic processes can occur without a net influx of energy from some other process? | back 17 C6H12O6 + 6 O2 6 CO2 + 6H2O |
front 18 Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's | back 18 activation energy |
front 19 When 10,000 molecules of ATP are hydrolyzed to ADP and Pi 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? | back 19 Reactant and product concentrations are not the same |
front 20 If an enzyme is added to a solution where its substrate and product are in equilibrium, what would occur? | back 20 Nothing; the reaction would stay at equilibrium |
front 21 Which of the following statements is a logical consequence of the second law of thermodynamics? | back 21 Every chemical reaction must increase the total entropy of the universe |
front 22 A number of systems for pumping 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. Small increases in calcium ions in the cytosol trigger a number of different intracellular reactions, so the cells must keep the calcium concentration quite low. Muscle cells also transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a muscle cell cytosol has a free calcium ion concentration of 10-7 in a resting cell, while the concentration in the SR can be 10-2, then how is the ATPase acting? | back 22 ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient |
front 23 Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as __________ is to __________. | back 23 exergonic; endergonic |
front 24 When you have a severe fever, what may be a grave consequence if this is not controlled? | back 24 change in the folding of enzymes |
front 25 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following terms best describes the reaction? | back 25 exergonic |
front 26 Refer to Figure 8.1 to answer the following questions. Which curve represents the behavior of an enzyme taken from a bacterium that lives in hot springs at temperatures of 70°C or higher? | back 26 curve 3 |
front 27 What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways? | back 27 energy coupling |
front 28 What must be the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in DNA and RNA? | back 28 There is no difference |
front 29 Competitive inhibitors block the entry of substrate into the active site of an enzyme. On which of the following properties of an active site does this primarily depend? | back 29 the ability of an enzyme to form a template for holding and joining molecules |
front 30 Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? | back 30 catabolism |
front 31 Use Figure 8.3 to answer the following questions. In coupled reactions, in which direction would the endergonic reaction be driven relative to the clockwise direction of the ATP reaction above and shown in the figure? | back 31 it would be shown in a clockwise direction at the top of the figure |
front 32 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: | back 32 +ΔG, +ΔH, -ΔS |
front 33 The following questions are based on the reaction A + B C + D shown in Figure 8.2. Which of the following represents the difference between the free-energy content of the reaction and the free-energy content of the products? | back 33 d |
front 34 Refer to Figure 8.1 to answer the following questions. Which curve was most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid? | back 34 curve 4 |
front 35 Which of the following is considered an open system? | back 35 an organism |
front 36 How does a noncompetitive inhibitor decrease the rate of an enzyme reaction? | back 36 by changing the shape of a reactant |
front 37 Which of the following is an example of potential rather than kinetic energy? | back 37 a food molecule made up of energy-rich macromolecules |
front 38 How can one increase the rate of a chemical reaction? | back 38 Add a catalyst |
front 39 Which of the following types of reactions would decrease the entropy within a cell? | back 39 dehydration reactions |
front 40 Which of the following statements is (are) true about enzyme-catalyzed reactions? | back 40 The reaction is faster than the same reaction in the absence of the enzyme |