Proteins

• The monomer in protein is ...

  amino acids
• The R-group in amino acids represents ...

  the variable side chain
• Polymerisation occurs via ...

  condensation reactions
• What bonds form between amino acids?

  peptide bonds
• Features of primary protein structure ...

  1. Sequence of amino acids in a chain
  2. Linked by peptide bonds only
• Features of secondary protein structure ...

  1. Folding of the primary structure to form alpha helices or beta-pleated sheets
  2. Alpha helix held in place by hydrogen bonds between the peptide bonds in the polypeptide chain
• Features of tertiary protein structure ...

  1. Further folding of the secondary structure to form specific 3D shapes - globular and fibrous
  2. R-groups interact to form bonds to maintain tertiary structure
  3. Bonds formed may be hydrogen, ionic, covalent, disulphide and hydrophobic
• Features of quaternary protein structure ...

  1. Formed from 2 or more polypeptide chains in tertiary form
  2. Held together by hydrogen bonding
• Haemoglobin has a quaternary structure ...

  1. Made from 4 polypeptide chains in tertiary formations
  2. 2 alpha subunits and 2 beta subunits
  3. It has a Fe2 prosthetic group
• Features of globular proteins ...

  1. Examples of globular proteins are enzymes, antibodies and hormones
  2. Their secondary structures are folded into complex spherical shapes
  3. Tertiary structure is important
  4. They are soluble in water
• Features of fibrous proteins ...

  1. Examples are collagen and keratin
  2. They tend to have structural roles
  3. They are insoluble
  4. They remain as long chains, their secondary structure is important
  5. They have alpha helices linked into strands