What is the primary function of enzymes?

Enzymes serve the crucial role of catalyzing biochemical reactions, which means they help speed up these processes by lowering the activation energy required for reactions to occur. This is essential in biological systems, where many reactions would not proceed at a sufficient rate to sustain life without the facilitation provided by enzymes. Enzymes are highly specific, meaning they typically catalyze only one type of reaction, leading to increased efficiency in metabolic pathways.

The other options represent important functions in biological systems but do not pertain to the specific role of enzymes. Structural support in cells is primarily provided by proteins like collagen in animal tissues. Antibodies, which are a type of protein produced by the immune system, are important for identifying and neutralizing pathogens, but they do not catalyze reactions. Transporting nutrients across cell membranes is a function of carrier proteins and channels, which facilitate the movement of substances in and out of cells, rather than the catalytic action of enzymes.