Question

Consider the following pathway:

A—> B —> C —>D —> choline (an alcohol found in lipids, whose structure you need to know for the exam.)

Inside growing cells the concentrations of compounds B, C, and D are very low. If you add drug X to growing cells, then compounds B and C accumulate and growth of cells is slower than normal.

Drug X probably inhibits

		A to B
		B to C
		C to D
		D to choline