Cell Review Cell Theory M - Pre-existing cells make cells. L - All living organisms are made of cells B - Basic structure and function of life. Levels of Organization Cells TissuesOrgansOrgan SystemsOrganismPopulation Organelle (Tiny rooms inside a cell – Organelles cannot live on their own.) REFER TO NOTES 9. Mitochondria – Eats protein to make energy (ATP) for the cell. (Powerhouse) 1. Nucleus – Command center of the cell. (Receives and sends messages) 6. Cell Membrane – Barrier of protection for the cell (Allows nutrients in and waste out) 8. Vacuole – Stores water and waste. 4. Chloroplasts – Makes food for the plant cell. 2. Cell Wall – Only in plants to give a rigid structure and add barrier of protection. 7. Ribosome – Creates protein Plant Cell 3. E.R. – Sends Protein 5. Cytoplasm – Holds organelles in jelly.