A School as a Cell
The school rules provide the school-cell's operating instructions.
Students, the district budget, and the PTA provide money which is like energy for the school-cell.
The front office orders paper, electronics, textbooks, cafeteria food, and all the materials the school needs to do its work: educating students. New kindergarteners are also new "materials."
We recycle, compost, and throw away trash to get rid of wastes. Graduating students are also waste, in a way.
When too many students are in the school, a new school with many of the same parts and pieces might be started nearby. Some of the students and teachers go to one school, and some stay at the original.
The cytoplasm of the school-cell is the campus.
The nucleus is the principal's office. In a school, the principal is responsible for everything that goes on in the school. He or she is the boss, very familiar with all the school rules, just like the nucleus controls what goes on inside the cell using the DNA as instructions. The nucleus is the "boss" of the cell.
The mitochondria is the copier machine that makes all the worksheets and tests for students to learn.
The cell membrane is the chain-link fence that keeps all the students inside. Security guards or school staff make sure that nobody gets on campus that's not supposed to be there.
Other organelles can be the different parts of the school-cell, like the library, cafeteria, classrooms, maintenance closet, locker room, etc.