What biomolecule makes up more than 50% of the dry weight of most cells and has various roles including structural support and defense?

Proteins are crucial biomolecules that make up more than 50% of the dry weight of most cells, serving a wide range of essential functions. They play a vital role in providing structural support, as seen in fibrous proteins like collagen found in connective tissues. Additionally, proteins are involved in defensive mechanisms, such as antibodies that help protect the body against pathogens. Their diverse functionality is attributed to the varied structure of proteins, which allows them to form enzymes, signaling molecules, and components of cellular machinery, contributing to cellular processes and overall organismal health. This multifaceted role underscores the significance of proteins in both structure and function within biological systems.