
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:
Activation energy is the energy required to metabolize the chemical reactions inside the cell leading to the formation of products from the reactants. This energy barrier is decreased by the help of enzyme involved in the metabolic process.
Answer to Problem 1MC
Correct answer:
Activation energy is required for the initiation of the exergonic reactions after the thermodynamic barrier is overcome by the enzyme catalyzing the metabolic thermodynamic reaction. Therefore, option (b) is correct.
Option (b) is given as “Activation energy is required to initiate exergonic reactions”.
Explanation of Solution
Justify reasons for the correct statement:
The catalysis of the metabolic reactions leading to the formation of products from reactants is overcome after crossing the energy barrier. The energy provided for overcoming this is provided by the activation energy required to initiate the process of exergonic reactions.
Hence, option (b) is correct.
Justify reasons for the incorrect statements:
Option (a) is given as “Enzymes increase activation energy requirements”. Enzymes decrease the activation energy of the metabolic reactions. Hence, it is a wrong answer.
Option (c) is given as “Heat cannot supply activation energy”. Activation energy is required to overcome the energy barrier of the metabolic reaction. Heat provides energy for the reaction to occur spontaneously. Hence, it is a wrong answer.
Option (d) is given as “Stomach acid inactivates pepsin”. Stomach acid initiates the formation of pepsin from pepsinogen. Hence, it is a wrong answer.
Hence, options (a), (c), and (d) are incorrect.
Activation energy is required for overcoming the energy barrier required for driving the exergonic process inside the cell.
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