Final answer:
Proteins function as buffers because they can bind hydrogen and hydroxyl ions, helping to maintain pH balance. They are composed of amino acids, which contribute to a myriad of cellular functions such as catalysis, structure, transport, and immune response. Option E)
Step-by-step explanation:
Proteins contain both acidic and basic R groups, making them capable of functioning as buffers. This characteristic allows proteins to bind hydrogen and hydroxyl ions, which helps maintain the pH balance in cells and blood. Nearly all proteins can perform this buffering action, contributing significantly to the overall buffering capacity within biological systems.
Furthermore, proteins are incredibly versatile macromolecules composed of amino acids that form long chains with diverse functionalities. They play a crucial role in cellular processes including acting as enzymes, which catalyze biochemical reactions, and as structural components that provide support within the cell. Proteins can also transport substances across the cell membrane, serve as antibodies, and function in cell signaling as hormones.