(a)[1]
Fig. 5.1 shows where papain acts on the antibody. State one function of this region in the intact antibody molecule.
(b(i))[1]
The three fragments, A, B and C still retain their ability to function. State what fragments A and B do.
(b(ii))[1]
The three fragments, A, B and C still retain their ability to function. State what fragment C does.
(c)[2]
In the antibody secreted by plasma cells, region X in Fig. 5.1 is hydrophilic, but in antibodies found on the surface of B-lymphocytes, region X is hydrophobic. Suggest why this difference exists.
(d(i))[1]
Papain is a globular protein with tertiary structure but no quaternary structure. State how many polypeptides make up one papain molecule.
(d(ii))[2]
Explain how the protein’s tertiary structure makes papain globular.