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1 | |
Activation energy is the energy required to |
| | A) | Get a reaction started. |
| | B) | Synthesize new compounds. |
| | C) | Break down incoming molecules. |
| | D) | All of the above. |
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2 | |
An enzyme is |
| | A) | A protein catalyst. |
| | B) | Under the direct control of the DNA. |
| | C) | A substance that lowers the activation energy. |
| | D) | All of the above. |
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3 | |
To be functional, an enzyme must |
| | A) | Have a specific three-dimensional shape. |
| | B) | Attach to a substrate, forming and enzyme-substrate complex. |
| | C) | Have a specific binding or attachment site. |
| | D) | All of the above. |
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4 | |
The induced fit hypothesis states that |
| | A) | The substrate will bend or fold to adjust itself to the enzyme. |
| | B) | The enzyme will bend or fold to adjust itself to the substrate. |
| | C) | The amount of enzyme produced will fit the needs of the substrate. |
| | D) | The amount of substrate will be kept constant by the enzyme itself. |
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5 | |
According to which of the patterns below are most enzymes named? |
| | A) | First the molecule involved; second the type of reaction; third the "-ase" ending. |
| | B) | First the type of reaction; second the molecule involved; third the "-ase" ending. |
| | C) | First the type of reaction; second some type of description; third the "-ase" ending. |
| | D) | The molecule involved and the reaction type are interchangeable - followed by the "-ase" ending. |
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6 | |
The term used for an enabling molecule is |
| | A) | Turnover regulator. |
| | B) | Binding protein. |
| | C) | Coenzyme. |
| | D) | NAD+. |
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7 | |
In general, an enzyme can catalyze __________ reactions per minute. |
| | A) | Between 102 and 105 |
| | B) | Between 103 and 1010 |
| | C) | Between 103 and 1016 |
| | D) | Between 104 and 1020 |
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8 | |
In enzyme-controlled reactions, an increase in temperature will usually |
| | A) | Speed up a reaction (without limits). |
| | B) | Speed up a reaction (within limits). |
| | C) | Slow down a reaction (without limits). |
| | D) | Slow down a reaction (within limits). |
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9 | |
Which statement(s) is/are true? |
| | A) | Enzymes generally have a functional temperature range that is identical to its optimal temperature range. |
| | B) | When an enzyme is denatured, its spatial structure is permanently changed. |
| | C) | Most enzymes are more sensitive to low temperatures than to high temperatures. |
| | D) | All of the above. |
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10 | |
Which statement(s) is/are true? |
| | A) | The three-dimensional structure of a protein leaves side chains exposed and thus subject to fluctuations in pH. |
| | B) | The environmental pH is important in determining the shape of the enzyme. |
| | C) | Each enzyme has its own pH range of activity. |
| | D) | All of the above. |
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11 | |
Mechanisms that ensure that an organism will carry out all metabolic processes in proper sequence are called |
| | A) | Control processes. |
| | B) | Enzymatic coordination processes. |
| | C) | Substrate inhibition processes. |
| | D) | Biochemical modulation sequences. |
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12 | |
Enzymatic competition occurs when |
| | A) | Gene regulator proteins interfere with enzymatic action. |
| | B) | Several different enzymes are available to combine with a given substrate. |
| | C) | The activator and repressor proteins bind to the substrate instead of the enzyme. |
| | D) | Several different substrates are present for a given enzyme. |
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13 | |
In negative-feedback inhibition, as the end product increases |
| | A) | Some of that end product binds to the substrate. |
| | B) | Some of that end product prevents the enzyme from performing properly. |
| | C) | Some of that end product binds concurrently to both the substrate and the enzyme. |
| | D) | Other genes produce competing enzymes and thus decrease the rate of the reaction. |
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14 | |
An inhibitor is a molecule that |
| | A) | Attaches itself to an enzyme and interferes with the formation of the enzyme-substrate complex. |
| | B) | Attaches itself to a substrate and interferes with the formation of the enzyme-substrate complex. |
| | C) | Binds to the enzyme-substrate complex and prevents the release of the end products. |
| | D) | Binds to the cell's DNA and prevents the formation of an enzyme. |
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15 | |
In competitive inhibition, the competitor |
| | A) | Binds to the coenzyme and thus disables the enzyme itself. |
| | B) | Interferes with enzyme production. |
| | C) | Attaches to the enzyme's active site, preventing the normal substrate from doing so. |
| | D) | Acts as a pseudo-enzyme and binds non-functionally to the substrate. |
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16 | |
A vitamin sometimes works as a(n): |
| | A) | enzyme. |
| | B) | inhibitor. |
| | C) | coenzyme. |
| | D) | catalyst. |
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17 | |
Competition between enzymes causes: |
| | A) | enzymes to denature. |
| | B) | decreases in the formation of certain products. |
| | C) | each enzyme to function better. |
| | D) | rearrangement of active sites. |
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18 | |
As the temperature of an enzyme controlled reaction is moderately increased, |
| | A) | changes in concentration of enzyme results. |
| | B) | fewer transitory molecules are formed. |
| | C) | decreases in turnover number occur. |
| | D) | more collisions occur so more of them are effective. |
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19 | |
Enzyme names frequently |
| | A) | include the name of the substrate. |
| | B) | ends in -ase. |
| | C) | indicate the type of reaction they facilitate. |
| | D) | all of the above. |
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20 | |
Turnover number: |
| | A) | increases as pH increases. |
| | B) | does not change relative to concentration of acid or base. |
| | C) | increases as optimum conditions are approached. |
| | D) | is constant. |
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21 | |
High temperatures can |
| | A) | denature an enzyme. |
| | B) | increase an enzyme's molecular motion. |
| | C) | change the protein structure of an enzyme. |
| | D) | all of the above. |
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22 | |
According to the induced-fit hypothesis |
| | A) | the presence of the substrate causes the enzyme to adjust itself to the substrate, this creates stress on substrate bonds. |
| | B) | enzymes and substrates fit perfectly together with "lock and key" precision. |
| | C) | coenzymes alter the shape of enzyme molecules. |
| | D) | inhibitors alter the shape of substrates. |
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23 | |
Coenzymes |
| | A) | are protein molecules. |
| | B) | are not altered during a reaction. |
| | C) | enable an enzyme to function. |
| | D) | all of the above. |
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24 | |
Which of the following is true? |
| | A) | All enzymes work best at a neutral pH. |
| | B) | There is an optimum pH for each specific enzyme. |
| | C) | Enzymes work well at any pH higher than optimum. |
| | D) | At a low pH, an enzyme needs more kinetic energy to function. |
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25 | |
With negative-feedback inhibition, as the number of end products increases, |
| | A) | enzyme activity decreases. |
| | B) | enzyme activity increases. |
| | C) | enzyme/substrate collisions become more effective. |
| | D) | inhibitors attach to substrates. |
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26 | |
Chemical messengers that tell the cell to decrease the production of a certain protein are |
| | A) | coenzymes. |
| | B) | gene-repressor proteins. |
| | C) | inhibitors. |
| | D) | denatured enzymes. |
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27 | |
Enzymes function by |
| | A) | lowering the activation energy required for a reaction. |
| | B) | increasing the temperature of the reaction. |
| | C) | providing activation energy to substrate molecules. |
| | D) | increasing the production of substrate. |
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28 | |
Inhibitor molecules |
| | A) | react with end-products. |
| | B) | attach to substrates. |
| | C) | lower activation energy. |
| | D) | attach to enzymes. |
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29 | |
To increase the amount of end-product produced in an enzyme facilitated reaction, you could |
| | A) | boil the enzyme. |
| | B) | add inhibitor. |
| | C) | add more substrate. |
| | D) | add ice. |
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