(a)[3]
If the gene needed for genetic engineering cannot be taken from the donor organism, it is instead made synthetically by using one of two methods. Outline the two methods for synthesising a gene for use in genetic engineering.
(b)[3]
DNA ligase and DNA polymerase are two enzymes used in genetic engineering. Complete Table 8.1 to show the functions of DNA ligase and DNA polymerase in genetic engineering. Use a tick ($\checkmark$) if the enzyme carries out the function, or a cross ($\times$) if it does not.
(c)[3]
The polymerase chain reaction (PCR) is used to produce many copies of a gene. A PCR cycle uses three temperatures. State the three temperatures used, and describe what occurs at each temperature during a PCR cycle.