Explain how enzyme function is like a lock and key.

The lock and key model states that the active site of an enzyme precisely fits a specific substrate. The induced fit model states that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit.

for the points

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.