What is the biological use of protein?

Proteins serve as essential molecules in biological systems, performing a wide range of functions. They act as enzymes, catalyzing biochemical reactions, and play critical roles in structural components, such as muscle fibers and cellular membranes. Additionally, proteins are involved in transport (e.g., hemoglobin carrying oxygen), immune responses (antibodies), and signaling processes (hormones). Overall, proteins are vital for growth, repair, and maintaining the overall function of living organisms.