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Which of the following is True?
a. Enzymes increase activation energy requirements.
b. Activation energy is required to initiate exergonic reactions.
c. Heat cannot supply activation energy.
d. Stomach acid inactivates pepsin.
Introduction:
Enzymes are mostly proteins that catalyze a reaction. Some reactions require a lot of energy input. These are called as endergonic reactions. The reactions that release energy are called as exergonic.
Answer to Problem 1MC
Correct answer:
Activation energy initiates reactions that are exergonic.
Explanation of Solution
Explanation for the correct answer:
Option (b) is given that to initiate an exergonic reaction, activation energy is required. This is true as activation energy refers to that minimum energy, which is necessary to carry a reaction even in the case of those that release energy at the end of the process. Hence, option (b) is correct.
Explanation for incorrect answers:
Option (a) is given that enzymes promote the need for higher activation energy. This statement is incorrect as enzymes work by lowering the activation energy and not the other way round. So, it is an incorrect option.
Option (c) is given that heat does not aid as activation energy. This is incorrect as heat increases the temperature; as a result, the reactant molecules involved collide faster and thus react quickly. So, it is an incorrect option.
Option (d) is given that pepsin is inactivated by the acid in the stomach. This is false as pepsin is the activated form. The inactive form, which is pepsinogen, is activated by hydrochloric acid that is released by the cells of the stomach. So, it is an incorrect option.
Hence, options, (a), (c), and (d) are incorrect.
Thus, it can be concluded that all reactions require activation energy be it exergonic or endergonic. It is whether these reactions release energy at the end determines their type.
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Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College