 |
1 | |
Enzymes cannot work outside the cells that synthesize them. (p. 84) |
| | A) | True |
| | B) | False |
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2 | |
Enzymes are not used up by the reactions they catalyze. (p. 84) |
| | A) | True |
| | B) | False |
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3 | |
The amount of energy released by a chemical reaction is much greater when it is catalyzed by an enzyme. (p. 85) |
| | A) | True |
| | B) | False |
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4 | |
An enzyme works by increasing the activation energy of a chemical reaction. (p. 85) |
| | A) | True |
| | B) | False |
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5 | |
The chemical reactions of living cells could not occur in the absence of enzymes. (p. 84) |
| | 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. (p. 85) |
| | 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). (p. 86) |
| | A) | True |
| | B) | False |
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8 | |
All enzyme names end with the suffix -ase. (p. 86) |
| | A) | True |
| | B) | False |
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9 | |
Enzymes do not increase the energy content of the reactants (or substrates). (p. 85) |
| | 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. (p. 84) |
| | A) | True |
| | B) | False |
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11 | |
Isoenzymes are enzymes with identical structures, but which perform different roles in different cells. (p. 86) |
| | 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. (p. 86) |
| | A) | True |
| | B) | False |
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13 | |
Skeletal and cardiac muscle have different forms of creatine phosphokinase. (p. 86) |
| | A) | True |
| | B) | False |
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14 | |
The rate of an enzymatic reaction depends on the concentration of enzyme present, but not on the concentration of the substrate. (p. 88) |
| | A) | True |
| | B) | False |
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15 | |
The higher the temperature, the faster the rate of an enzymatic reaction will be. (p. 87) |
| | A) | True |
| | B) | False |
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16 | |
Human enzymes all have approximately the same temperature optimum, but highly varied pH optima. (p. 87) |
| | A) | True |
| | B) | False |
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17 | |
Although these enzymes selectively remove phosphate groups, the phosphatase from the prostate functions best at a lower pH than the phosphatase from bone tissue. (p. 88) |
| | 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. (p.88) |
| | 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. (p. 88) |
| | A) | True |
| | B) | False |
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20 | |
Cofactors are metal ions 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.(p. 88) |
| | 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. (p. 89) |
| | A) | True |
| | B) | False |
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22 | |
The reversal of some enzyme-catalyzed reactions may require a different set of enzymes than the ones that make the reaction go in a forward direction. (p. 89) |
| | A) | True |
| | B) | False |
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23 | |
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). (p. 89) |
| | 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. (p. 89) |
| | 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. (p. 89) |
| | 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. (p. 89) |
| | A) | True |
| | B) | False |
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27 | |
Allosteric inhibitors bind directly to the active site of an enzyme to keep it from interacting with its normal substrate. (p. 89) |
| | 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. (p. 90) |
| | A) | True |
| | B) | False |
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29 | |
Albinism is the result of an inherited defect in an enzyme that produces skin pigment. (p. 91) |
| | 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. (p. 93) |
| | A) | True |
| | B) | False |
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31 | |
Entropy is a measure of the amount of free energy in a system. (p. 92) |
| | A) | True |
| | B) | False |
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32 | |
Photosynthesis is an endergonic reaction.(p. 92) |
| | 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. (p. 93) |
| | 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. (p. 92) |
| | A) | True |
| | B) | False |
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35 | |
The complete oxidation of glucose to CO2 + H2O is an exergonic reaction. (p. 92) |
| | 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 pile of glucose. (p. 92) |
| | A) | True |
| | B) | False |
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37 | |
One Calorie will raise the temperature of one liter of water one degree Celsius. (p. 93) |
| | A) | True |
| | B) | False |
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38 | |
A cell must maintain a state of low entropy to stay alive. (p. 93) |
| | A) | True |
| | B) | False |
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39 | |
All exergonic reactions in a cell are directly linked to endergonic reactions. (p. 93) |
| | 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. (p. 93) |
| | A) | True |
| | B) | False |
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41 | |
Reduction means a process in which an atom or molecule gains electrons. (p. 93) |
| | A) | True |
| | B) | False |
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42 | |
Oxidation means a reaction in which some atom or molecule combines with oxygen. (p. 94) |
| | A) | True |
| | B) | False |
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43 | |
In the course of performing its role, an oxidizing agent becomes oxidized. (p. 94) |
| | A) | True |
| | B) | False |
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44 | |
It is impossible for an oxidation reaction to occur without a reduction reaction occurring simultaneously along with it. (p. 94) |
| | A) | True |
| | B) | False |
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45 | |
If a molecule picks up two hydrogen atoms, it becomes reduced. (p. 94) |
| | 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 from one to the other. (p. 94) |
| | 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. (p. 95) |
| | A) | True |
| | B) | False |
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48 | |
NADH is a reducing agent. (p. 95) |
| | A) | True |
| | B) | False |
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49 | |
NAD is derived from niacin, a water soluble vitamin known as B3. (p. 95) |
| | 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. (p. 95) |
| | 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 of the body, you can get extra energy by eating riboflavin supplements. (p. 95) |
| | A) | TRUE |
| | B) | FALSE |
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52 | |
In a hypothetical reaction XH2 + Y X + YH2, the compound Y is an oxidizing agent. (p. 94) |
| | A) | TRUE |
| | B) | FALSE |
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53 | |
In a hypothetical reaction XH2 + Y X + YH2, the ompound Y becomes oxidized. (p. 94) |
| | A) | TRUE |
| | B) | FALSE |
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2002 McGraw-Hill Higher Education