Which of the following statements about enzymes is not true?

They raise the activation energy needed

HESI A2 Entrance Exam Biology

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Question 1

Do enzymes catalyze reactions?

Your Answer: Option(s)

Correct Answer: Option(s) A

Rationale

Enzymes catalyze reactions.

Enzymes are biological catalysts that accelerate chemical reactions by lowering the activation energy required for the reaction to proceed. This catalytic function is essential for various metabolic processes in living organisms, enabling them to efficiently convert substrates into products.

A) Catalyze
Enzymes are specifically designed to catalyze biochemical reactions, facilitating the transformation of substrates into products through their active sites. This ability to accelerate reactions without undergoing permanent changes themselves is a defining characteristic of enzymes, ensuring that biological processes occur at rates necessary for life.

B) Inhibit
While some enzymes can act as inhibitors in certain contexts (for example, competitive inhibitors that prevent substrate binding), the primary function of enzymes is not to inhibit reactions. Instead, they promote reactions, and inhibition is generally a regulatory mechanism rather than a direct catalytic function.

C) Stop
Enzymes do not stop reactions; rather, they serve to enhance and speed up the rate at which reactions occur. Stopping a reaction typically involves a lack of substrates or the addition of inhibitors, neither of which reflects the fundamental role of enzymes. Their purpose is to facilitate, not to halt, biochemical processes.

D) None of the above
This choice is incorrect as it suggests that enzymes do not catalyze reactions at all. Since the definition of enzymes inherently includes their catalytic function, this option misrepresents the essential role that enzymes play in biological systems.

Conclusion
Enzymes are vital biological catalysts that accelerate reactions by lowering activation energy, thereby enabling metabolic processes to occur efficiently. Among the choices, "catalyze" accurately reflects the primary function of enzymes, while the other options misrepresent their roles in biochemical reactions. Understanding enzyme function is crucial for fields such as biochemistry, medicine, and biotechnology, where manipulation of enzyme activity can lead to significant advancements.

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Enzymes catalyze reactions.

Enzymes lower the activation energy needed for reactions.

Epithelial cells are polarized.

It is an example of a negative feedback loop.

All of the above.

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Enzymes catalyze reactions.

Enzymes lower the activation energy needed for reactions.

Epithelial cells are polarized.

It is an example of a negative feedback loop.

All of the above.

Free Preview Ended

Unlock Full Access

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