Explain why enzyme A is referred to as an inducible enzyme.
Protein B has a role similar to the protein encoded by gene Y of the $lac$ operon. Suggest a possible function for protein B that would allow yeast cells to make use of galactose.
Calculate the percentage of Msn2 molecules in the cell that are found inside the nucleus when glucose is absent. Show your working and give your answer to two significant figures.
When glucose is present, $26\%$ of the Msn2 molecules in the cell are inside the nucleus. Suggest why this value differs from your answer to (i).
Another way to tag molecules with a fluorescent colour is to use monoclonal antibodies with GFP attached. These monoclonal antibodies bind specifically to the target molecule. This is known as immunofluorescent tagging. Suggest reasons why immunofluorescent tagging would not be a suitable method for this investigation.