What serves as a biological catalyst in the body?

Enzymes serve as biological catalysts in the body by accelerating chemical reactions without undergoing any permanent changes themselves. They lower the activation energy required for reactions to occur, thereby increasing the rate at which those reactions take place. This is crucial in biological systems, where many reactions would occur too slowly to sustain life without the action of enzymes.

For example, in metabolic pathways, enzymes facilitate various processes such as digestion and energy production. Their specificity allows them to interact with specific substrates to produce particular products, making them vital for the regulation and efficiency of biological processes.

Other options, such as receptors, hormones, and electrons, play essential roles in biological functions but do not act as catalysts. Receptors are involved in signal transduction, hormones are chemical messengers that coordinate activities across different systems, and electrons are subatomic particles that play a role in chemical bonding and energy transfer, but none of these perform the catalytic functions that enzymes do in biological reactions.