Aminoacids

• All proteins are made by stringing together a common set of 20 kinds of amino acids.
• Every amino acid consists of a central carbon atom bonded to four covalent partners.
• • All 20 amino acids have…
  • a carboxyl group (—COOH).
  • an amino group (—NH2).
  • a hydrogen atom.
  • A variable component that is called side chain (or R group, for radical group), which gives its special chemical properties.