Noun
A small air cell, or globular space, in the interior of organic cells, either containing air, or a pellucid watery liquid, or some special chemical secretions of the cell protoplasm.
Source: Webster's dictionaryA vacuole is surrounded by a membrane called the tonoplast (word origin: Gk tón(os) + -o-, meaning “stretching”, “tension”, “tone” + comb. form repr. Source: Internet
Another function of a central vacuole is that it pushes all contents of the cell's cytoplasm against the cellular membrane, and thus keeps the chloroplasts closer to light. Source: Internet
For example, when the pH in the cells environment drops, the H + ions surging into the cytosol can be transferred to a vacuole in order to keep the cytosol's pH constant. citation In animals, vacuoles serve in exocytosis and endocytosis processes. Source: Internet
Fungi Vacuoles in fungal cells perform similar functions to those in plants and there can be more than one vacuole per cell. Source: Internet
If high salt concentrations are seen within the vacuole, a high concentration gradient will be established between the vacuole and the cytoplasm, leading to high levels of energy investment to maintain this state. Source: Internet
In plant cells, vacuoles cover anywhere from 30% to 90% of the total cell volume. citation Most mature plant cells contain one large central vacuole encompassed by a membrane called the tonoplast. Source: Internet