Amino Acid - compound with an amino group and a carboxyl group attached to a central carbon

• Proteins make up 50% of dry mass of cells in our bodies
• E.g. of proteins are
  • Hemoglobin (carries O in blood), immunoglobin (immune system), fibrin (blood clots), collagen (cartilage between bones), enzymes (biological catalysts), keratin (hair and nails)
• Proteins are polymers of specific sequences of amino acids folded into specific 3-d shapes
• Proteins can have 1+ chains of amino acids called peptide chains