(a(i))[2]
With reference to Fig. 3.1, state which two protein structure levels are shown.
(a(ii))[1]
State the name of the structures that keep the two polypeptide chains linked together.
(b)[3]
Many people with diabetes have to receive regular insulin injections. The insulin shown in Fig. 3.1 cannot be swallowed because proteases in the gut would hydrolyse it. In the space below, draw a diagram to show how the peptide bond between glutamine 15 and leucine 16 in polypeptide chain A could be hydrolysed and show the products of the hydrolysis.