12. Microbial Metabolism

Which of the following statements is TRUE regarding an enzyme's function?

a) It is generally increased if the structure or conformation of an enzyme is altered.

b) It is independent of factors such as pH and temperature.

c) It increases the rate of chemical reactions by lowering activation energy barriers.

DRAW IT An enzyme and substrate are combined. The rate of reaction begins as shown in the following graph. To complete the graph, show the effect of increasing substrate concentration on a constant enzyme concentration. Show the effect of increasing temperature.

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The graph shows an enzyme-catalyzed reaction.

a. Draw a line that would correspond to a noncatalyzed reaction.

b. Is this an endergonic or exergonic reaction? How can you tell?

c. Label the point on your graph that corresponds with the activation energy.

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Activation energy ______.

a. is the amount of energy required during an activity such as flagellar motion

b. requires the addition of nutrients in the presence of water

c. is lowered by the action of organic catalysts

d. results from the movement of molecules