If a cell was like a school, what would mitochondria's job be?

Mitochondria are one of the many cell organelles found in plant and animal cells.  The job of the mitochondria is to provide the cell with energy in the form of ATP (adenosine triphosphate).  This occurs through a process called cellular respiration.

If you were to look for a place in a school to compare the mitochondria to, you could pick the school cafeteria.  The job of the cafeteria is to provide students and staff with meals that will give them energy throughout the day.  Think of it this way.  You wake up late and do not have time to eat breakfast before you leave the house.  You arrive at school just in time for the first class to start, so there goes your chance for breakfast at school.  As the day moves along, you begin to feel hungry, tired, and weak.  Lunchtime comes along and you eat.  Once you finish your meal, you begin to feel better.  Because of the food provided by the cafeteria, you will now have the energy you need to make it through the remainder of the day.