Which of the following is NOT a characteristic of enzymes?

• A. They increase the rate of chemical reactions
• B. They are consumed in the reaction
• C. They lower the activation energy of reactions
• D. They are specific to certain substrates

Answer: (B)

Enzymes are biological catalysts that accelerate chemical reactions, making them occur more rapidly. One of their key characteristics is that they are not consumed in the reactions they catalyze. This means that after facilitating a reaction, they remain unchanged and can participate in additional reaction cycles.

Enzymes also function by lowering the activation energy required for reactions to proceed, which contributes to their efficiency in promoting metabolic processes. Additionally, they exhibit specificity, meaning that each enzyme typically catalyzes a specific reaction or acts on a particular substrate, ensuring that biochemical pathways operate in a controlled manner.

The assertion that enzymes are consumed in reactions is not accurate, as this would imply that they would become depleted, which contradicts their role as catalysts. Overall, the defining properties of enzymes include their ability to accelerate reactions, reduce activation energy, and maintain their integrity to act repeatedly upon substrates, highlighting the importance of their non-consumptive nature in facilitating biochemical processes.