What is the primary function of proteins in organisms?

Proteins play a crucial role in the biological systems of organisms primarily by providing structure and facilitating biochemical reactions. Structural proteins, such as collagen in connective tissues and keratin in hair and nails, are essential for maintaining the shape and integrity of cells and tissues. Additionally, many proteins function as enzymes, which are catalysts that accelerate chemical reactions necessary for various biological processes.

Enzymes lower the activation energy required for reactions to occur, making it possible for the organism to efficiently carry out metabolism, digestion, and other vital functions. The versatility of protein structures allows them to perform a wide range of functions, from signaling and transport to immune responses. This multifunctionality underscores the central role that proteins play in the overall function and regulation of biological systems.