(a)[3]
Fill in Table 6.1 so that it compares the structure of an mRNA molecule with that of a DNA molecule.
(b(i))[1]
State the name of stage 1 shown in Fig. 6.1.
(b(ii))[2]
Describe what occurs at stage 2, shown in Fig. 6.1, to reduce the length of the RNA molecule.
(c(i))[4]
Cotransporter molecules are proteins made in companion cells. Fig. 6.2 shows what occurs in the cytoplasm of a companion cell to a transfer RNA molecule before cotransporter proteins can be made. Describe the role of the transfer RNA shown in Fig. 6.2 in the synthesis of a cotransporter protein.
(c(ii))[3]
Outline the function of cotransporter proteins in companion cells.