Pennsylvania Esthetician State Board Practice Exam

What role do enzymes play in chemical reactions?

1. Speed up reactions by providing energy

2. Dissolve and break down large molecules into smaller ones

3. Change the end products of a reaction

4. Decrease the activation energy of a reaction

The correct answer is: Dissolve and break down large molecules into smaller ones

Enzymes serve an important role in biochemical reactions by acting as catalysts, primarily achieving this by decreasing the activation energy needed for a reaction to occur. This means that they facilitate the reaction process, allowing it to happen more easily and quickly without themselves being consumed. While enzymes can also be involved in breaking down large molecules into smaller ones (a function closely associated with certain types of enzymes, particularly digestive enzymes), the most fundamental aspect of their function in chemical reactions is their ability to lower activation energy, thus making reactions proceed faster and more efficiently. In the context of your choices, the selection regarding enzymes dissolving and breaking down large molecules captures one aspect of enzyme function, but it overlooks the broader and more critical role of activation energy reduction, which is key to understanding how enzymes catalyze chemical reactions. Therefore, while option B touches on an important function of enzymes, it does not capture the essential mechanism by which enzymes operate across various reactions in a biological context.