The saclike storage structure found in both plant and animal cells is the vacuole.

Here's why:

* Plant cells: Vacuoles in plant cells are large and central, often taking up most of the cell's volume. They store water, nutrients, and waste products, help maintain turgor pressure (keeping the plant rigid), and play a role in cell growth and development.

* Animal cells: Vacuoles in animal cells are smaller and more numerous than in plant cells. They primarily function in storage of water, nutrients, and waste products, but also play roles in autophagy (breaking down cellular components) and endocytosis (taking in materials from the outside).

While both types of cells have vacuoles, their size and function differ slightly.