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1 | | Enzymes cannot work outside the cells that synthesize them. |
| | A) | True |
| | B) | False |
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2 | | When an enzyme catalyzes a chemical reaction some of the enzyme is lost. |
| | A) | True |
| | B) | False |
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3 | | The amount of energy released by a chemical reaction is much greater when an enzyme catalyzes it. |
| | A) | True |
| | B) | False |
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4 | | An enzyme works by decreasing the activation energy of a chemical reaction. |
| | A) | True |
| | B) | False |
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5 | | The chemical reactions of living cells could not occur in the absence of enzymes. |
| | A) | True |
| | B) | False |
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6 | | A substrate molecule binds to certain amino acids that line the active site of an enzyme. |
| | A) | True |
| | B) | False |
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7 | | Hydrolases are enzymes that remove water from organic molecules (that is, remove -H and -OH chemical groups and produce water as a reaction product, known as dehydration). |
| | A) | True |
| | B) | False |
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8 | | All enzyme names end with the suffix -ase. |
| | A) | True |
| | B) | False |
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9 | | Enzymes increase the energy content of the reactants (or substrates). |
| | A) | True |
| | B) | False |
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10 | | One reason enzymes are so effective is that each enzyme can catalyze a broad range of metabolic reactions. |
| | A) | True |
| | B) | False |
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11 | | Isoenzymes are enzymes that perform the same function in different cells and have slightly different chemical structures. |
| | A) | True |
| | B) | False |
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12 | | The active sites of isoenzymes are not affected by the structural differences that distinguish one isoenzyme from another. |
| | A) | True |
| | B) | False |
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13 | | Skeletal and cardiac muscle have different forms of creatine phosphokinase. |
| | A) | True |
| | B) | False |
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14 | | The rate of an enzymatic reaction depends on the concentration of the substrate but not the concentration of the enzyme. |
| | A) | True |
| | B) | False |
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15 | | The higher the temperature, the faster the rate of an enzymatic reaction will be. |
| | A) | True |
| | B) | False |
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16 | | Human enzymes all have approximately the same temperature optimum, but highly varied pH optima. |
| | A) | True |
| | B) | False |
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17 | | Although these enzymes selectively remove phosphate groups, the phosphatase isolated from the prostate functions best at a higher pH than the phosphatase isolated from bone tissue. |
| | A) | True |
| | B) | False |
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18 | | Many enzymes cannot function when they are completely purified and isolated from their natural chemical surroundings. |
| | A) | True |
| | B) | False |
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19 | | Metal ions that aid the function of enzymes can be called either coenzymes or cofactors for those enzymes. |
| | A) | True |
| | B) | False |
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20 | | Coenzymes are organic molecules that sometimes bind to the active site of an enzyme along with its substrate in order for the enzyme to function at its optimal rate. |
| | A) | True |
| | B) | False |
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21 | | Carbonic anhydrase is an enzyme that can catalyze the breakdown of carbonic acid (H2CO3) into carbon dioxide (CO2) and water (H2O), but it cannot catalyze the reverse reaction. |
| | A) | True |
| | B) | False |
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22 | | If there is a reversible chemical reaction between two molecules A and B, and more B than A is present at a given moment, then the law of mass action predicts this reaction will go toward the left (that is, more B will be converted to A). |
| | A) | True |
| | B) | False |
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23 | | For most metabolic pathways a single enzyme catalyzes all the reactions. |
| | A) | True |
| | B) | False |
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24 | | The nine-step enzymatic conversion of glucose to pyruvic acid is a metabolic pathway. The one-step enzymatic conversion of CO2 and H2O to carbonic acid is not. |
| | A) | True |
| | B) | False |
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25 | | An intermediate in a metabolic pathway may serve as the substrate for two or more different enzymes that catalyze reactions leading in different directions. |
| | A) | True |
| | B) | False |
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26 | | Some metabolic end-products can deactivate or inhibit the very enzymes that are responsible for their production. |
| | A) | True |
| | B) | False |
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27 | | Allosteric inhibitors bind at a site other than the active site to decrease enzyme activity. |
| | A) | True |
| | B) | False |
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28 | | Suppose enzyme3 catalyzes the third step in a metabolic pathway where intermediate G is converted to intermediate H. An inborn error of metabolism resulting in a defective enzyme3 would result in a surplus of G and deficiency of H. |
| | A) | True |
| | B) | False |
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29 | | Albinism is the result of an inherited defect in an enzyme that produces skin pigment. |
| | A) | True |
| | B) | False |
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30 | | The fundamental point of cellular metabolism is to increase the amount of entropy in the system. |
| | A) | True |
| | B) | False |
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31 | | Entropy is a measure of the amount of free energy in a system. |
| | A) | True |
| | B) | False |
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32 | | Photosynthesis is an endergonic reaction. |
| | A) | True |
| | B) | False |
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33 | | The human body is unable to carry out any endergonic reactions because it does not have any photosynthetic pigments and cannot synthesize organic nutrients. |
| | A) | True |
| | B) | False |
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34 | | When glucose is burned in a dish, it breaks down to CO2 + H2O. This demonstrates that the glucose contains more energy than the CO2 + H2O it was made from. |
| | A) | True |
| | B) | False |
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35 | | The complete oxidation of glucose to CO2 + H2O is an exergonic reaction. |
| | A) | True |
| | B) | False |
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36 | | The oxidation of 1 gram of glucose to CO2 + H2O will release more calories when done in small, enzymatically-controlled steps within a cell than when done in a single step by simply touching a match to a 1 gram of glucose. |
| | A) | True |
| | B) | False |
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37 | | One Calorie will raise the temperature of one liter of water one degree Celsius. |
| | A) | True |
| | B) | False |
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38 | | A cell must maintain a state of high entropy to stay alive. |
| | A) | True |
| | B) | False |
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39 | | Exergonic reactions in a cell are often directly coupled to endergonic reactions. |
| | A) | True |
| | B) | False |
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40 | | The endergonic reaction to which most exergonic reactions of a cell are linked is ATP → ADP + Pi + Energy. |
| | A) | True |
| | B) | False |
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41 | | When a molecule is reduced the molecule will gain one or more electrons. |
| | A) | True |
| | B) | False |
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42 | | Oxidation means a reaction in which some atom or molecule combines with oxygen. |
| | A) | True |
| | B) | False |
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43 | | In the course of performing its role, a reducing agent becomes oxidized. |
| | A) | True |
| | B) | False |
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44 | | It is impossible for an oxidation reaction to occur without a reduction reaction occurring simultaneously. |
| | A) | True |
| | B) | False |
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45 | | If a molecule picks up two hydrogen atoms, it becomes reduced. |
| | A) | True |
| | B) | False |
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46 | | It is possible for the same molecule to serve as both an oxidizing agent and a reducing agent, alternating between the oxidized and reduced forms. |
| | A) | True |
| | B) | False |
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47 | | The structure of the coenzyme NAD is very similar to the structure of the universal energy carrier ATP. |
| | A) | True |
| | B) | False |
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48 | | NADH is a reducing agent. |
| | A) | True |
| | B) | False |
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49 | | NAD is derived from niacin, a water-soluble vitamin known as B3. |
| | A) | True |
| | B) | False |
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50 | | FAD can accept two electrons and become FADH2, but NAD can only accept one electron and become NADH. |
| | A) | True |
| | B) | False |
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51 | | Since the vitamin riboflavin (vitamin B2) is converted to a coenzyme that transfers electrons in the energy-producing reactions, eating riboflavin supplements provides extra energy. |
| | A) | True |
| | B) | False |
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52 | | In a hypothetical reaction XH2 + Y → X + YH2, the compound X is a reducing agent. |
| | A) | True |
| | B) | False |
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53 | | In a hypothetical reaction XH2 + Y → X + YH2, the compound Y becomes oxidized. |
| | A) | True |
| | B) | False |
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