What are the basic building blocks of proteins?

Proteins are macromolecules crucial for many functions in living organisms and are composed of basic units known as amino acids. Amino acids link together in specific sequences to form polypeptides, which then fold into functional proteins. There are 20 different amino acids that can combine in various ways to create the vast diversity of proteins found in nature, each with specific properties and functions that are vital for processes like structure, catalysis, transport, and signaling in biological systems.

The other options refer to different biological molecules with distinct roles. Nucleotides are the building blocks of nucleic acids like DNA and RNA, vitamins are organic compounds that organisms need in small quantities for various biochemical functions, and fatty acids are components of lipids, which primarily serve as energy sources and structural components of cell membranes. Understanding the unique building blocks and their roles helps clarify the overall structure and function of different biomolecules.