In biochemistry, what is the basic building block (monomer) of a protein?

• A. Amino acid
• B. Nucleotide
• C. Fatty acid
• D. Monosaccharide

Answer: (A)

Verified step by step guidance

1. Understand that proteins are large biomolecules made up of smaller units called monomers.
2. Recall that the monomers of proteins are specifically called amino acids, which link together via peptide bonds to form polypeptides.
3. Recognize that nucleotides are the monomers of nucleic acids (DNA and RNA), not proteins.
4. Know that fatty acids are components of lipids, and monosaccharides are the monomers of carbohydrates, so neither are building blocks of proteins.
5. Conclude that the basic building block (monomer) of a protein is an amino acid.