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A vacuole (/ ˈ v æ k juː oʊ l /) is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. [ 1 ] [ 2 ] Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution , though in certain cases ...
Organelles (literally "little organs") are usually membrane-bound structures inside the cell that have specific functions. Some major organelles that are suspended in the cytosol are the mitochondria , the endoplasmic reticulum , the Golgi apparatus , vacuoles , lysosomes , and in plant cells, chloroplasts .
In the 1830s, Félix Dujardin refuted Ehrenberg theory which said that microorganisms have the same organs of multicellular animals, only minor. [ 4 ] Credited as the first [ 5 ] [ 6 ] [ 7 ] to use a diminutive of organ (i.e., little organ) for cellular structures was German zoologist Karl August Möbius (1884), who used the term organula ...
Pigments that color the cell are sometime located in the cell sap. Vacuoles can also increase the size of the cell, which elongates as water is added, and they control the turgor pressure (the osmotic pressure that keeps the cell wall from caving in). Like lysosomes of animal cells, vacuoles have an acidic pH and contain hydrolytic enzymes.
Some cells, most notably Amoeba, have contractile vacuoles, which can pump water out of the cell if there is too much water. The vacuoles of plant cells and fungal cells are usually larger than those of animal cells. Vacuoles of plant cells are surrounded by a membrane which transports ions against concentration gradients.
By scientific convention, the term lysosome is applied to these vesicular organelles only in animals, and the term vacuole is applied to those in plants, fungi and algae (some animal cells also have vacuoles). Discoveries in plant cells since the 1970s started to challenge this definition. Plant vacuoles are found to be much more diverse in ...
The eukaryotic cell is thought to have arisen when an ancestral archaeal cell internalized an aerobic bacterium (the proto-mitochondrion). Mans et al. [ 5 ] proposed that the evolutionary development of the eukaryotic cell nucleus was triggered by this archaeo-bacterial symbiosis .
The diameter of the vacuole can occupy around 80% of the cell's diameter. [11] Thus for a 1 mm diameter cell, the vacuole can have a diameter of 0.8 mm, leaving only a path width of about 0.1 mm around the vacuole for cytoplasm to flow. The cytoplasm flows at a rate of 100 microns/sec, the fastest of all known cytoplasmic streaming phenomena. [8]