What are the building blocks of proteins?

Proteins are macromolecules essential for a wide range of biological functions, and they are made up of smaller units known as amino acids. Each amino acid consists of an amino group, a carboxyl group, and a unique side chain, which determines its specific properties and role in protein structure and function.

When proteins are synthesized, amino acids are linked together by peptide bonds in a specific sequence dictated by the genetic code. This sequence ultimately determines the protein's three-dimensional structure and its biological activity. Proteins play critical roles in structural support, enzymes, transport, signaling, and immune responses, making amino acids fundamental to life.

The other choices—nucleotides, fatty acids, and monosaccharides—are building blocks of different types of biological macromolecules. Nucleotides are the components of nucleic acids like DNA and RNA, fatty acids are the building blocks of lipids, and monosaccharides are the basic units of carbohydrates. Therefore, only amino acids are the appropriate building blocks for proteins, highlighting their unique role in biochemistry.