(a(i))[1]
State the name of the process at A.
(a(ii))[2]
Name the protein-synthesis stages shown at E and at F.
(a(iii))[4]
Identify organelles B, G, H and J.
(b)[3]
Describe the changes to the bacteria between C and D.
(c)[2]
Macrophages act as antigen presenting cells (APCs). Antigens from pathogens such as the bacteria in Fig. 2.1 are shown to helper T-lymphocytes as in Fig. 2.2. Only a very small number of helper T-lymphocytes react to APCs by binding in the manner shown in Fig. 2.2. Suggest why this happens.