Future Biotechnology on Instagram: "Proteins are made of 20 amino acids, each with a unique side chain (R group) that defines how proteins fold and function. These amino acids are linked by peptide bonds to form polypeptides, which fold into complex 3D structures. Protein structure has 4 levels: 1️⃣ Primary – amino acid sequence 2️⃣ Secondary – α-helix & β-sheet 3️⃣ Tertiary – 3D shape from side chain interactions 4️⃣ Quaternary – multiple polypeptides forming one unit They’re classified based o