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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 .
Compartmentalization is a feature of prokaryotic photosynthetic structures. [2] Purple bacteria have "chromatophores", which are reaction centers found in invaginations of the cell membrane. [2] Green sulfur bacteria have chlorosomes, which are photosynthetic antenna complexes found bonded to cell membranes. [2]
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 ...
They are larger than vesicles and their specific function varies. The operations of vacuoles are different for plant and animal vacuoles. In plant cells, vacuoles cover anywhere from 30% to 90% of the total cell volume. [32] Most mature plant cells contain one large central vacuole encompassed by a membrane called the tonoplast.
Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.
Cellular compartments in cell biology comprise all of the closed parts within the cytosol of a eukaryotic cell, usually surrounded by a single or double lipid layer membrane. These compartments are often, but not always, defined as membrane-bound organelles. The formation of cellular compartments is called compartmentalization.