Enzymes are _. Select one: a. carbohydrate or protein in composition b. not needed for catabolic reactions c. used up in chemical reactions d. broken down in reactions that require energy input e. proteins that function as catalysts
The Correct Answer and Explanation is:
The correct answer is e. proteins that function as catalysts.
Explanation:
Enzymes are biological molecules, typically proteins, that act as catalysts in biochemical reactions. Their primary function is to speed up (or catalyze) chemical reactions without being consumed or permanently altered in the process. Let’s break down the options:
- a. Carbohydrate or protein in composition:
While most enzymes are proteins, some RNA molecules (known as ribozymes) also have catalytic properties. However, the majority of enzymes are proteins, not carbohydrates. So, this statement is partially true but doesn’t fully define enzymes. - b. Not needed for catabolic reactions:
This is incorrect. Enzymes are crucial for both anabolic (building up) and catabolic (breaking down) reactions. Without enzymes, these processes would occur too slowly to sustain life. - c. Used up in chemical reactions:
This is false. Enzymes are not used up in the reactions they catalyze. They can be reused many times, as they are not consumed during the reaction. - d. Broken down in reactions that require energy input:
Enzymes are not typically broken down in reactions. Instead, they remain intact after catalyzing a reaction and can continue to catalyze subsequent reactions. - e. Proteins that function as catalysts:
This is the correct answer. Enzymes are proteins that speed up biochemical reactions by lowering the activation energy needed for the reaction to occur. They do so by binding to substrates and converting them into products. Since enzymes are not consumed in the reaction, they can be used repeatedly.
Enzymes are essential for various biological processes, including digestion, metabolism, and DNA replication, among others. Their ability to reduce the energy barrier of reactions makes life processes efficient and possible under normal physiological conditions.
