The entire ATP apparatus is also called the ATP_______

Question

I think it is Synthesis but not sure.

ATP synthesis is a process.
apparatus is a noun.
you need a noun.

ATP----------------?

I can't seem to think of an appropriate word. Sometimes I seriously wopnder about the teachers that make up these questions.

Is it then Synthase?

atp synthase is a noun, but only refers to a specific enzyme in the process.