Proteins are formed by linking amino acids into long chains called what?

• A. Polypeptides
• B. Nucleic acids
• C. Monosaccharides
• D. Lipids

Answer: (A)

Proteins are built by linking amino acids into long chains through peptide bonds. That chain is called a polypeptide, and a protein may consist of one or several polypeptides folded into a functional shape. The other terms refer to different biomolecules: nucleic acids are the DNA/RNA polymers made from nucleotides, monosaccharides are simple sugar units that form carbohydrates, and lipids are fats and oils not built from amino acid chains.