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56 Cards in this Set
- Front
- Back
Why do we have storage macromolecules, such as fats, in our bodies? |
A. We can break down these macromolecules to provide energy for the endergonic reactions in our bodies. |
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2. Energy is defined as: |
B. the capacity to do work. |
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3. The amount of energy available to do work is called: B. free energy |
B. free energy |
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4. The energy needed to destabilize existing chemical bonds and start a chemical reaction is called: |
A. activation energy |
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Based on the graph, what are the optimal temperatures for the human enzyme and hotsprings prokaryote enzyme?
A. The optimal temperature for the human enzyme is 30 degrees C. The optimal temperature for the hotsprings prokaryote enzyme is 60 degrees C. |
B. The optimal temperature for the human enzyme is 40 degrees C. The optimal temperature for the hotsprings prokaryote enzyme is 72 degrees C. |
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6. A drug binds to the active site of an enzyme. If it is bound to the active site of the enzyme, it prevents substrate binding. This drug would be considered a: |
D. competitive inhibitor |
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7. A particular reaction has a negative delta G. However, this reaction takes many years to proceed in the absence of enzyme. Why is this the case? |
D. A certain amount of activation energy is required for the reaction to proceed |
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8. A molecule that closely resembles the shape of a substrate for an enzyme would most likely serve as a: |
C. competitive inhibitor |
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9. Oxidation and reduction reactions are chemical processes that result in a gain or loss of: |
C. electrons. |
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10. The synthesis of sugar molecules through the process of photosynthesis requires energy absorbed from sunlight. Bearing this in mind, what kind of reaction is photosynthesis? |
B. endergonic |
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11. A particular chemical reaction is exergonic. What can you say about the relationship between the reactants and the products in this exergonic reaction? |
A. The reactants have more free energy than the products |
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12. Kinases are enzymes that can phosphorylate (transfer phosphate groups onto) macromolecules such as proteins. A particular kinase, Kinase 1 is known to promote cell division. It promotes cell division by phosphorylating Protein X. Phosphorylation of Protein X activates Protein X. Once activated, Protein X stimulates the production of other proteins such as Protein Y and Z that directly promote cell division. In order to function, Kinase 1 requires the presence of Metal A. However, in the presence of Protein A, Kinase 1 is nonfunctional. From the description, what is considered the substrate of Kinase 1? |
A. Protein X |
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13. Kinases are enzymes that can phosphorylate (transfer phosphate groups onto) macromolecules such as proteins. A particular kinase, Kinase 1 is known to promote cell division. It promotes cell division by phosphorylating Protein X. Phosphorylation of Protein X activates Protein X. Once activated, Protein X stimulates the production of other proteins such as Protein Y and Z that directly promote cell division. In order to function, Kinase 1 requires the presence of Metal A. However, in the presence of Protein A, Kinase 1 is nonfunctional. From the description, what is considered a cofactor of Kinase 1? |
D. Metal A |
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14. Hexokinase is an enzyme that binds specifically to glucose and converts it into glucose 6-phosphate. The activity of hexokinase is suppressed by glucose 6-phosphate, which binds to hexokinase at a location that is distinct from the active site. This is an example of what? |
A. Feedback inhibition |
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15. The organic non-protein components that aid in enzyme functioning are called: |
C. coenzymes. |
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16. The inorganic non-protein components that participate in enzyme catalysis are known as: |
B. cofactors. |
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17. Many metabolic pathways are ultimately concerned with ATP; either with the generation of ATP, or with the requirement of ATP for that pathway to function. Why is ATP so important to metabolism? |
C. The phosphate groups of ATP are held together by unstable bonds that can be broken to release energy |
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18. The chemistry of living systems representing all chemical reactions is called |
C. metabolism. |
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19. A calorie is the commonly used unit of chemical energy. It is also the unit of: |
D. heat. |
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20. The term oxidation is derived from the name of the element oxygen. This is reasonable, because oxygen: |
A. attracts electrons very strongly. |
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21. When an atom or molecule gains one or more electrons, it is said to be: |
D. reduced. |
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22. The ultimate source of energy for humans comes from what source? |
A. The sun |
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23. Glucose is broken down through cellular respiration, which involves a large number of chemical reactions. At the end of the cellular respiration process, a large number of ATP molecules are generated, but yet, not all of the possible energy that is contained in a molecule of glucose can be harnessed through these chemical reactions to generate ATP. In other words, during cellular respiration, not all of the energy that is contained in a molecule of glucose is converted into the energy stored in ATP. What happened to the remaining energy? |
D. It is lost as heat |
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24. The Law of Thermodynamics that states that energy cannot be created or destroyed is: |
A. The First Law of Thermodynamics |
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25. The Law of Thermodynamics that states that increases in entropy are favored is: |
B. The Second Law of Thermodynamics |
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26. A current problem in modern medicine is the development of drug resistance mutations. This occurs when a mutation arises in a patient making him/her resistant to a drug and thus rendering the drug useless in treating a specific disease. Many useful drugs are competitive inhibitors of specific enzymes, and the drug-resistance mutations prevent the binding of the drug. These types of mutations, in addition to preventing competitive inhibitor binding, can also sometimes reduce the activity of the enzyme. Why is that the case? |
D. These mutations most likely change the shape of the active site of the enzyme |
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27. Tacrolimus (FK-506) is a drug that inhibits an enzyme called calcineurin. Calcineurin is a protein phosphatase. This is an enzyme that dephosphorylates (removes phosphate groups from) proteins. When added to cells, tacrolimus can inhibit the dephosphorylation of a protein called NFAT, but it cannot prevent the dephosphorylation of a protein called CDK1. What is the most likely explanation for this finding? |
B. NFAT is a substrate of calcineurin, but CDK1 is not |
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28. RNA molecules that also act as enzymes are given the name: |
A. ribozymes |
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29. In an enzyme-catalyzed reaction, the reactant is called the: |
C. substrate |
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30. When the substrate is bound to the enzyme, the shape of the enzyme may change slightly, leading to: |
A. an induced fit |
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31. In order to reuse an enzyme after the conclusion of an enzyme catalyzed reaction, what must occur? |
B. the enzyme has to separate itself from the product |
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32. You are working with a specific enzyme-catalyzed reaction in the lab. You are a very careful experimentalist, and as a result, at the beginning of each of your experiments, you measure the temperature in the lab. On days 1 through 5, the temperature in the lab was 20oC. Today is day 6 of your experiment, and the temperature in the lab is 30oC. How do you predict that this will alter the rate of your enzyme-catalyzed reaction? |
C. It could possibly increase or decrease the rate |
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33. Metabolic reactions fall under two general categories: anabolic and catabolic. What type of chemical reactions are these two classes of metabolic reactions? |
D. Anabolic reactions are endergonic reactions, whereas catabolic reactions are exergonic. |
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34. Under standard conditions, ATP can release for every molecule converted to ADP |
C. 7.3 Kcal of energy. |
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35. Glucose is converted into glucose 6-phosphate by hexokinase. Glucose 6-phosphate then serves as the substrate for the enzyme phosphoglucose isomerase, which converts this reactant into fructose 6-phosphate. Fructose 6-phosphate serves as the substrate for phosphofructokinase, which converts fructose 6-phosphate into fructose 1,6-bisphosphate. Based on the information provided, this is an example of what? |
C. A metabolic pathway |
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36. In an experiment described in a chemistry lab book, the directions state that after mixing two chemicals (A and B) and waiting 5 minutes that A will be oxidized. This means that: |
A. chemical A has lost electrons to chemical B. |
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37. In a chemical reaction, glyceraldehyde-3-phosphate + NAD+ yields 1,3-bisphosphoglycerate + NADH. In this reaction, what happened to NAD+? |
B. It was reduced to form NADH |
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38. In a chemical reaction, 1,3-bisphosphoglycerate + ADP yields 3-phosphoglycerate plus ATP. What is the delta G for this reaction? |
B. Less than zero. |
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39. For a particular chemical reaction, the enthalpy of the reactants is -400 kJ. The enthalpy of the products is -390 kJ. The entropy of the reactants is 0.2 kJ/K. The entropy of the products is 0.3 kJ/K. The temperature of the reaction is 25oC. What can you conclude about this reaction? |
A. It is exergonic |
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40. Does ADP contain the capacity to provide energy for the cell? |
D. Yes. Cleaving the bond between the terminal phosphate and the phosphate attached to the ribose sugar can provide energy for the cell. |
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41. AMP-activated protein kinase (AMPK) is an enzyme that is activated by high levels of AMP in cells. If levels of AMP are high in cells, that means that levels of ATP are low. Once active, AMPK activates catabolic pathways and inhibits anabolic pathways in the cell. Why do you think that is the case? Choose the answer that best explains the role of AMPK. |
C. By activating catabolic pathways, AMPK provides a mechanism to activate exergonic pathways, which is important if AMP levels are high in the cell. |
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42. You are studying an enzyme-catalyzed reaction that induces a particular cellular activity in the lab. If you wanted to slow down that particular cellular activity by controlling the enzyme, what could you do? |
A. Decrease the temperature of the incubator where the cells are growing |
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43. A new antibiotic has been developed that inhibits the activity of an enzyme by competitive inhibition. What effect will this have on the activation energy of the enzyme-catalyzed reaction? |
C. The activation energy required for the reaction in the presence of the antibiotic will be the same as the activation energy required in the absence of the antibiotic |
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44. A new antibiotic has been developed. It acts as a noncompetitive inhibitor. How will this antibiotic affect delta G for the enzyme-catalyzed reaction? |
C. Delta G will be unaffected |
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45. Glycolysis is a metabolic process that is done by all cells. However, not all cells make use of another metabolic process called the Krebs cycle. What does this tell you about the evolution of these processes? |
A. As a metabolic process, glycolysis likely evolved prior to the Krebs cycle |
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46. Enzyme 1 converts substrate A into product B. Is this an example of a metabolic pathway? |
B. No. This only describes one chemical reaction. A metabolic pathway includes multiple chemical reactions. |
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47. It is summer, and you are excited about going to your local amusement park, and specifically about riding the new roller coaster that was just built. You imagine waiting at the top of the stairs for the roller coaster to pull into the station, climbing into the car, strapping yourself into the seatbelt, and pulling down the harness. You can imagine the cars slowly chugging up to the top of the first hill, coming down on the other side, and the excitement you expect to feel as you go along for the ride. Of all of the things that you have imagined, which is an example of potential energy? |
A. Waiting at the top of the stairs for the roller coaster to pull into the station |
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48. Phosphofructokinase (PFK) is an enzyme that converts fructose 6-phosphate to fructose 1,6-bisphosphate, by adding a phosphate group. This is the first committed step of the metabolic pathway of glycolysis, and thus it is very tightly regulated. AMP binds to PFK at a site distinct from the binding site for fructose 6-phosphate, and stimulates the formation of fructose 1,6-bisphosphate. ATP binds to PFK at a site distinct from the binding site for fructose 6-phosphate, and inhibits the formation of fructose 1,6-bisphosphate. There are other regulators of this enzyme as well. What is the role of AMP in this example? |
D. Allosteric activator |
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49. You eat a bowl of beans as part of your dinner. As you digest the beans, the proteins that are present get broken down to their component amino acids. As your body destroys the macromolecules that were present in the beans, is the energy present in those molecules destroyed? |
C. No. The energy contained within these macromolecules is converted into other forms of chemical energy and kinetic energy, though some is lost as heat. |
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50. While standing at the top of the stairs, you have a potential energy of 40 Joules. If you walk all the way down the stairs, what would your potential energy be at the bottom of the stairs? |
A. 0 Joules |
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51. If you were able to increase the kinetic energy of the molecules inside your body, how would this affect your body temperature? |
A. It would increase |
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52. You return home to find that your baby brother has scattered his toy trains and trucks all over the floor of your room. As you begin to pick up the toys and put them away, you realize that even though he is just a baby, he has clearly mastered: |
B. the second law of thermodynamics. |
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53. If the G of a reaction was -31.45 kJoules, you would know that: |
D. the reaction is spontaneous. |
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54. In the hypothetical biochemical pathway, P Q + R S T, which step is likely to have evolved first? |
D. S T |
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55. While conducting an experiment, you realize that a competitive inhibitor was interfering with your reaction. How could you overcome this problem? |
C. Increase the concentration of the correct substrate in the reaction. |
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56. A ribozyme catalyzes a reaction on itself and actually changes shape. This is an example of what? |
C. Intramolecular catalysis |