Question

A booth has set up two identical chemical reactions in clear containers: one contains an enzyme and immediately starts bubbling vigorously, while the other container without the enzyme shows only a few bubbles after 5 minutes of waiting. What essential role do enzymes play in chemical reactions?

Answer 1

Enzymes are biological catalysts. Their essential role is to speed up chemical reactions by lowering the activation energy required to reach the transition state.

Key points:
- They bind substrates at an active site and stabilize the transition state (and/or provide an alternative reaction pathway), which makes the reaction proceed far faster than it would without the enzyme.
- They are not consumed by the reaction and do not change the overall free-energy change or the final equilibrium—only the rate at which equilibrium is reached.
- They are specific for particular substrates and work best under particular conditions (pH, temperature).

In your booth example, the enzyme-containing reaction bubbles vigorously because the enzyme greatly increases the reaction rate; the same chemistry without the enzyme proceeds only slowly, so you see few bubbles after 5 minutes.