(a)[5]
The polymerase chain reaction (PCR) may be used to generate many copies of a gene for transfer. Describe and explain the stages involved in PCR.
(b(i))[4]
Scientists built a gene called tTav and transferred it into the eggs of A. stephensi. Describe how the tTav gene could have been made and moved into the eggs of A. stephensi.
(b(ii))[1]
Suggest how the tTav protein stops other genes from being expressed in A. stephensi.
(b(iii))[1]
Genetically engineered A. stephensi larvae were treated with tetracycline in the laboratory. Suggest why A. stephensi larvae were treated with tetracycline in the laboratory.