A cell can be compared to any organism that counts on different parts that have to fulfill their role for the sake of t's correct functioning, ex: a factory, a machine.
A cell can be compared to the school because every organel has a function to fulfill in order to keep the whole cell functioning in the right way. If any of the organells fails, the cell itself has to check what is wrong with it, and if the problem persists, the cell may die or replace it. The same happens with the school, it counts on different parts (teachers, directives, etc.) and if any of those parts fails, it has to be replaced before the structure itsellf gets damaged.
