The large sac that stores food and other materials in a cell is called a vacuole.

Here's a breakdown:

* Vacuoles are membrane-bound organelles found in plant, fungal, and some animal cells.

* Function: Their primary role is storage, holding water, nutrients, waste products, and other cellular materials.

* Size: Vacuoles can be quite large, sometimes taking up most of the cell's volume.

* In plants: Vacuoles play a crucial role in maintaining cell turgor pressure (rigidity), helping the plant stand upright. They also store pigments that give flowers their color.

Let me know if you have any other questions!