A vacuole (ˈvækjuːoʊl) is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these. The organelle has no basic shape or size; its structure varies according to the requirements of the cell.
Contractile vacuoles ("stars") were first observed by Spallanzani (1776) in protozoa, although mistaken for respiratory organs. Dujardin (1841) named these "stars" as vacuoles. In 1842, Schleiden applied the term for plant cells, to distinguish the structure with cell sap from the rest of the protoplasm.
In 1885, de Vries named the vacuole membrane as tonoplast.
The function and significance of vacuoles varies greatly according to the type of cell in which they are present, having much greater prominence in the cells of plants, fungi and certain protists than those of animals and bacteria. In general, the functions of the vacuole include:
Isolating materials that might be harmful or a threat to the cell
Containing waste products
Containing water in plant cells
Maintaining internal hydrostatic pressure or turgor within the cell
Maintaining an acidic internal pH
Containing small molecules
Exporting unwanted substances from the cell
Allows plants to support structures such as leaves and flowers due to the pressure of the central vacuole
By increasing in size, allows the germinating plant or its organs (such as leaves) to grow very quickly and using up mostly just water.
In seeds, stored proteins needed for germination are kept in 'protein bodies', which are modified vacuoles.
Vacuoles also play a major role in autophagy, maintaining a balance between biogenesis (production) and degradation (or turnover), of many substances and cell structures in certain organisms.
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
The eukaryotes constitute the domain of Eukaryota (juːˈkærioʊts,_-əts), organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms are eukaryotes. They constitute a major group of life forms, alongside the two groups of prokaryotes, the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but due to their generally much larger size, their collective global biomass is much larger than that of prokaryotes.
Plants are eukaryotes, predominantly photosynthetic, that form the kingdom Plantae. Many are multicellular. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi. All current definitions exclude the fungi and some of the algae. By one definition, plants form the clade Viridiplantae (Latin for "green plants") which consists of the green algae and the embryophytes or land plants. The latter include hornworts, liverworts, mosses, lycophytes, ferns, conifers and other gymnosperms, and flowering plants.
A fungus (: fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which, by one traditional classification, includes Plantae, Animalia, Protozoa, and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls.
Explores proximity-specific ribosome profiling and translational dynamics with high resolution, covering spatial regulation, cell architecture, ER's role, and advanced techniques.
Mitochondria are essential organelles participating in numerous cellular functions, including energy harvesting, regulation of homeostasis and apoptosis. Changes in mitochondrial number, morphology, and function not only impact cellular metabolism but also ...
The symbiotic planktonic foraminiferaOrbulina universainhabits open ocean oligotrophic ecosystems where dissolved nutrients are scarce and often limit biological productivity. It has previously been proposed thatO. universameets its nitrogen (N) requiremen ...
ROYAL SOC2020
The bacterium Vibrio cholerae is the causative agent of the diarrheal disease cholera, which affects millions of people every year. Apart from being a human pathogen, V. cholerae is also a common member of aquatic habitats. Whilst the mechanism that allow ...