A Cell is like a Theatre
The endplasmic reticulum in a cell is like the usher in a theater because the ER transport synthesized proteins to the Golgi like the usher does to the people to get to their seats.
The plasma membrane in a cell is like the doors in a theater because a plasma membrane lets things go in and out of a cell and protects it like doors let people enter and exit and protect them from weather and other people outside.
The ribosomes in a cell is like the advertising for a theater because the ribosomes create protein for a cell like the tickets create an audience.
The lysosomes in a cell are like the trash containers in a theater because the lysosomes in a cell collect waste and keep it out of the way of other organelles like the containers do for the theater.
The mitochondria in a cell are like the people/audience in a theater because the mitochondria keep the cell full of energy and the audience is what creates the revenue and keeps the theater alive or in business.
The cytoplasm in a cell is like the seating in a theater because like how the cytoplasm surrounds the cell, the seating surrounds the stage.