The cell membrane is like the gates or a forcefield of the cell. It is a flexible wrapping outside the cell, and is made out of proteins. It separates the stuff inside of the cell from the outside.
The cell membrane holds the cell together and protects the cell. It controls what goes into the cell and what goes out of the cell.
What I've drawn here is the cell membrane up close. The middle part is a channel - where things go in and out of the cell.
Wow, we've learned so much about the cell, and about so many organelles! Do you want to know which organelle you are like the most? Let's go to the Personality Quiz.