Final answer:
Nonprotein catalysts in living organisms are known as enzymes, which are essential for facilitating biochemical reactions by lowering the activation energy, hence speeding up the reaction rate without being consumed.
Step-by-step explanation:
Nonprotein catalysts are known as enzymes. Enzymes are biological catalysts that are vital for various biochemical reactions occurring within living organisms. These catalysts are typically composed of protein or ribonucleic acid (RNA) and function by lowering the activation energy of chemical reactions, therefore increasing the rate at which these reactions occur without being consumed in the process. The substances on which enzymes act are called substrates. While most enzymes are proteins, RNA-based catalysts known as ribozymes also exist and perform similar functions to protein enzymes.