Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What role do enzymes play in chemical reactions?

1. They slow down reactions

2. They initiate digestion

3. They absorb heat

4. They speed up reactions

The correct answer is: They speed up reactions

Enzymes serve as biological catalysts that facilitate and accelerate chemical reactions within living organisms. They do this by lowering the activation energy required for reactions to occur, which means that the reactions can happen more quickly and efficiently at the physiological temperatures present in biological systems. Enzymes provide an alternative pathway for the reaction, increasing the rate at which reactants are converted into products without being consumed in the process. This vital role is essential in many biological functions, such as metabolism, where timely reactions are critical for maintaining homeostasis and overall health. While some processes may involve digestion or heat absorption, these are not the primary functions of enzymes. Enzymes primarily focus on increasing the speed of reactions, making them indispensable to life as they enhance the efficiency of biochemical processes.