Name the organelle which controls osmotic pressure in a cell

The organelle that controls osmotic pressure in a cell is the vacuole.

Explanation

• In plant cells, the large central vacuole is filled with cell sap (a solution of water, sugars, salts, and other substances).
• The vacuole maintains turgor pressure, which is the osmotic pressure exerted by the fluid inside the vacuole against the cell wall.
• This pressure helps the cell retain its shape, prevents wilting in plants, and regulates the movement of water in and out of the cell.

Thus, the vacuole is the key organelle for osmotic regulation.