Plant Cell Central Vacuole: Structure and Function

What is the central vacuole in a plant cell and where is it located?

The central vacuole in a plant cell is a large organelle that maintains water concentration, supports cell expansion without synthesizing new cytoplasm, and contains cell sap to exert turgor pressure.

Answer:

The central vacuole in a plant cell is a large organelle that maintains water concentration, supports cell expansion without synthesizing new cytoplasm, and contains cell sap to exert turgor pressure.

The central vacuole is a vital organelle located in the plant cell, and usually it occupies most of the cell's volume. Its primary role is maintaining the cell's concentration of water, particularly in changing environmental conditions. For instance, when a plant is not watered, the central vacuole loses water and shrinks, leading to wilting as the cell wall becomes unsupported.

The central vacuole also holds crucial responsibilities, such as supporting cellular expansion when it absorbs water, thereby increasing the cell size without the high energy cost of synthesizing new cytoplasm. Furthermore, the central vacuole contains cell sap, a mixture of water, enzymes, ions, salts, and sometimes toxic substances that can deter herbivory.

It is enclosed by a membrane known as the tonoplast, which features proteins that regulate water flow, thereby maintaining turgor pressure against the cell wall.