In proteins, what is the monomer unit that links together to form a polypeptide chain?

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

Answer: (C)

Verified step by step guidance

1. Understand that proteins are polymers made up of repeating units called monomers.
2. Recall that the monomers of proteins are amino acids, which link together to form polypeptide chains.
3. Recognize that nucleotides are the monomers of nucleic acids (DNA and RNA), not proteins.
4. Know that monosaccharides are the monomers of carbohydrates, and fatty acids are components of lipids, neither of which form proteins.
5. Therefore, identify amino acids as the correct monomer unit that links together to form a polypeptide chain in proteins.