Plant Cell Anatomy - Enchanted Learning In plant cells, ATP is produced in the cristae of mitochondria and chloroplasts. cell membrane - the thin layer of protein and fat that surrounds the cell, but is inside the cell wall. The cell membrane is semipermeable, allowing some substances to pass into the cell and blocking others. Cell wall A thick, rigid membrane that surrounds a plant cell. This layer of cellulose fiber gives the cell most of its support and structure.