water

Xylem

... plants , the xylem is the tissue that carries water up the root and stem. In trees , it constitutes ... walls of vessel elements are perforated, enabling water to flow through vessels. Xylem cells are also known as tracheary elements . This name was applied b...

Vacuole

...en vacuoles in the same cell), but is principally water . Water tends to move along concentration gradien... . A contractile vacuole is used to pump excess water out of the cell to reduce osmotic pressure and keep the cell from bursting. Contractile vacuoles a...

Turgor

...membrane that is permeable to a solvent such as water but not to solutes. A biological cell , for exam...nd other substances. In a hypotonic environment, water flows across the plasma membrane into the cell (since the concentration of water is lower inside t...

Thermoregulation

...re which is stabilized by the unique properties of water within the bodies of organisms including animals; ... evaporation - evaporative cooling occurs when water (often from perspiration) leaves the skin surface as a gas, lowering the body temperature by cooling...

Stoma

...interior exits through these same openings. Also, water vapor is released into the atmosphere through the...of stomata on the upper epidermis can then prevent water loss. Monocotyledons are different. For their leaves are held vertically, they will have the sam...

Starch

...d that is prepared by mixing a vegetable starch in water (earlier preparations also had to be boiled), and is used in the laundering of clothes . During the 19th century and early 20th century, it was stylish to stiffen the collars and sleeves of men's shirts and the ruffles of girls' petticoats by...

Signal transduction

...t extracellular chemical signals have affinity for water and are unable to penetrate the oily barrier posed by the membrane that surrounds cells. A common kind of extracellular signal is nutrient . In complex organism this includes the ligands responsible for sensations of smell and taste. Steroids rep...

Semen

...itish , milky fluid, very viscous , containing water and small amounts of salt , protein , and fructose . Contents showTocToggle("show","hide") 1 Composition 2 Semen and transmission of disease 3 Cultural views 4 See also 5 References 6 External links Composi...

Redox

...very complex electron transfer processes, to yield water and carbon dioxide. The term redox comes from t...e 2 O 3 . Burning of hydrocarbons to produce water , carbon dioxide , some partially oxidized forms, and heat energy . Complete oxidation of material...

Protist

...ulds , which are spore-forming amoeboids, and the water moulds and labyrinthulids . The latter two are ...considerable changes. Except for the ciliates and water moulds, the traditional groups are polyphyletic and frequently overlap. Newer systems attempt to ...

Protist

...ulds , which are spore-forming amoeboids, and the water moulds and labyrinthulids . The latter two are ...considerable changes. Except for the ciliates and water moulds, the traditional groups are polyphyletic and frequently overlap. Newer systems attempt to ...

Protein

...proteins will not remain in solution in distilled water . A protein that loses its native state is said to be denatured . Denatured proteins generally have no secondary structure other than random coil. A protein in its native state is often described as folded . One of the more striking discoveries ...

Primary nutritional groups

...e. g. the photosynthetic production of starch from water and CO 2 ). It should be noted that the terms aerobic respiration , anaerobic respiration and fermentation are not referring to primary nutritional groups, but simply reflect the different use of possible electron acceptors in the energy ...

Potential energy

...on of an object such as a rock on top of a hill or water behind a dam . It is written as where m is the mass of the object, g the acceleration due to gravity and h the height above a chosen reference level (typical units would be kilograms for m , metres/second 2 for g , and metre...

Polysaccharide

...and of glucose units. Starches are insoluble in water . They can be digested by hydrolysis catalyzed by ...ules by the addition of a phosphate, rather than a water as in hydrolysis . This process yields phosphorylated glucose molecules, which can be metabolized ...

Plasmolysis

...tion of cells within plants due to the loss of water through osmosis . It is the cell membrane peeling...ay from its cell wall. This phenomenon occurs when water is drawn out of the cell and into the extracellular (outside cell) fluid. The movement of water occu...

Plant

... desiccation, and vascular tissues which transport water throughout the organism. In many the sporophyte acts as a separate individual, while the gametophyte remains small. The first primitive seed plants, Pteridosperms (seed ferns) and Cordaites, both groups now extinct, appeared in the late Devonian an...

Plant

... desiccation, and vascular tissues which transport water throughout the organism. In many the sporophyte acts as a separate individual, while the gametophyte remains small. The first primitive seed plants, Pteridosperms (seed ferns) and Cordaites, both groups now extinct, appeared in the late Devonian an...

Physiology

... organisms that do not dwell in aquatic habitats , water must be stored within their cellular environments. In organisms such as these, dehydration becomes a major issue. Dehydration in humans can occur during elevated physical activity. Within the field of exercise physiology , studies have been ...

Alga

...r algae, called seaweeds , grow mostly in shallow water and provide distinctive habitats. Microscopic forms, called phytoplankton , provide the food base for marine food chains . Phytoplankton can be present in high densities, called algal blooms , which might be visible as a discoloration of the wat...

Photorespiration

...the underside of the leaf ) are closed to prevent water loss. The reaction is: RuBP + rubisco + O 2 → phosphoglycolate The glycolate is then sent to peroxisomes . Photorespiration is a wasteful process because no PGAL is created. PGAL is used to create nearly all of the food and structure...

Photosynthesis

.... Most notably, they use carbon dioxide gas and water to produce sugars and oxygen gas. The energy for these processes comes from photosynthesis. For instance, the over-all equation for the production of glucose is: 12H 2 O + 6CO 2 + light → C 6 H 12 O 6 (glucose) + 6O 2 + 6H 2 O The g...

Light-dependent reaction

... drive a transfer of electrons and hydrogen from water (or some other donor molecule) to an acceptor call...ctrons and a single proton (hydrogen nucleus). The water or some other donor molecule is split in the process; it is the light reaction which produces waste ...

Photolysis

...urned into chemical energy which is used to split water into hydrogen and oxygen . The oxygen is released as a byproduct while the hydrogen binds with the coenzyme NADP to form NADPH . Photolysis is also a process in the atmosphere by which primary pollutants such as hydrocarbons and nitrog...

Lipid bilayer

...ion Color scheme: PO4 = green, N(CH3)3 = violet, water = blue, terminal CH3 = yellow, O = red, glycol C =...s, certain kinds of lipids alone in a test tube of water will self-organize to form a "bilayer". The bilayer is composed of two opposing layers of lipid mo...

Phloem

...t quite living) companion cell. While movement of water and minerals through the xylem is driven by negati...ransporting solute molecules into it. This causes water to move into the sieve-tube element by osmosis , creating pressure that pushes the sap down the tub...

Phospholipid

...ature, the head of a phospholipid is attracted to water (it is hydrophilic ). The nonpolar head is not attracted to water and is said to be hydrophobic . When placed in water, phospholipids form a bilayer , where the hyd...

Peptide bond

...p of the other molecule, releasing a molecule of water (H 2 O). This is a dehydration synthesis reaction... are metastable , meaning that in the presence of water they will break spontaneously, releasing about 10 kJ / mol of free energy , but this process is e...

Passive transport

... article: Filtration Filtration is movement of water and solute molecules across the cell membrane due ...cle: Osmosis Osmosis is basically diffusion of water molecules. Most cell membranes are permeable to water, and since the diffusion of water plays such a...

Parthenogenesis

...ts (called agamospermy ), invertebrates (e.g. water fleas , aphids ) and some vertebrates (e.g. lizards , salamanders , some fish , and even turkeys ). Parthenogenetic populations are typically all-female.As with all types of asexual reproduction , there are both costs and benefits associated ...

Redox

...very complex electron transfer processes, to yield water and carbon dioxide. The term redox comes from t...e 2 O 3 . Burning of hydrocarbons to produce water , carbon dioxide , some partially oxidized forms, and heat energy . Complete oxidation of material...

Osmoregulation

...luids to maintain the homeostasis of the body's water content, that is it keeps the body from becoming ... Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution th...

Osmosis

...y because it provides the primary means by which water is transported into and out of cells . Conte...nd protein. When the cells are placed in solution, water rushes in to the area of high solute concentration, bursting the cell. Many plant cells do not bur...

Nephron

... The basic function of the nephron is to regulate water and soluble substances (especially ions ) in the... liquid, known as glomerular filtrate , contains water , glucose , salt , amino acids , and urea . Proximal tubule The valuable molecules, water ,...

Magnetic resonance imaging

...organisms as well as detecting the amount of bound water in geological structures. It is primarily used to ... property of T2 weighting. On a T2 weighted scan, water and fluid-containing tissues are bright (most modern T2 sequences are actually fast T2 sequences,...

Animal

...onges are sessile and typically feed by drawing in water through pores all over the body, which is supported by a skeleton typically divided into spicules. The extinct Archaeocyatha , which have fused skeletons, may represent sponges or a separate phylum. Among the eumetazoan phyla, two are radially s...

Marine biology

...include everything from the tiny layers of surface water in which organisms and abiotic items may be trappe...here solid objects are rare and the surface of the water is the only visible boundary. A large (exactly how large is unknown at this point) proportion of al...

Long-term potentiation

...g.) Both groups were then subjected to the Morris water maze , in which rats were placed into a pool of murky water and tested on how quickly they could locate a platform hidden beneath the water's surface. Rats in ...

Lipid

... in a polar environment, the polar molecules (i.e. water in an aqueous solution) become more ordered around...e. Therefore, in an aqueous environment, the polar water molecules form an ordered "clathrate" cage around the dissolved nonpolar molecule. However, when the...

Lipase

A Lipase is a water - soluble enzyme that catalyzes the hydrolysis of ester bonds in waterinsoluble, lipid substrates. Most lipases act at a specific position on the glycerol backbone of a lipid substrate (A1, A2 or A3). In the example of human pancreatic l...

Life

... Margulis ) as an autopoietic (self-producing), water based, lipid - protein bound, carbon metabolic, nucleic acid replicated, protein readout system "a system of inferior negative feedbacks subordinated to a superior positive feedback " ( J. theor Biol. 2001 ) Tom Kinch's definition of life...

Light-dependent reaction

... drive a transfer of electrons and hydrogen from water (or some other donor molecule) to an acceptor call...ctrons and a single proton (hydrogen nucleus). The water or some other donor molecule is split in the process; it is the light reaction which produces waste ...

Leaf

...uttation take place. Leaves can store food and water , and are modified in some plants for other purpos...ermis serves several functions: protection against water loss, regulation of gas exchange, secretion of metabolic compounds, and (in some species) absorption...

Citric acid cycle

..., fats and proteins into carbon dioxide and water in order to generate energy. It is the second of three metabolic pathways that are involved in fuel molecule catabolism and ATP production. The citric acid cycle also provides precursors for many compounds such as certain amino acids , and ...

Kidney

...a ) from the blood and excrete them, along with water , as urine . The medical field that studies the k...ion in each normal adult kidney. Nephrons regulate water and soluble matter (especially electrolytes ) in the body by first filtering the blood, then reabso...

Insulin

...proximately 45 g (1 1/2 ounces) in the total body water (which obviously includes more than merely blood and will be usually about 60% of the total body weight in men). This homeostatic effect is the result of many factors, of which hormone regulation is the most important. There are two groups of m...

Hydrolytic enzyme

...ing hydrolysis ( hydro-,"water";lysis-,"break" ) a water molecule is added to the polymer and cleaves the covalent bond holding the two monomers. The reverse of a hydrolysis reaction is a condensation reaction ....

Hydrolysis

...d into two parts by the addition of a molecule of water . This is distinct from a hydration reaction , in which water molecules are added to a substance, but no cleavage occurs. Types Hydrolysis of an ester link ...

Human

...d eventually starvation , while failure to obtain water leads to dehydration and thirst . Both starvati...t human settlements are dependent on proximity to water and, depending on the lifestyle, other natural resources such as fertile land for growing crops a...

Homeostasis

...are as follows: The regulation of the amounts of water and minerals in the body. This is known as osmoreg... remove urea , and adjust the concentrations of water and a wide variety of ions . Most of these organs are controlled by hormones secreted from t...

Photosynthesis

.... Most notably, they use carbon dioxide gas and water to produce sugars and oxygen gas. The energy for these processes comes from photosynthesis. For instance, the over-all equation for the production of glucose is: 12H 2 O + 6CO 2 + light → C 6 H 12 O 6 (glucose) + 6O 2 + 6H 2 O The g...

Herpetology

...hambered heart like fish, and are often bound to water for at least some part of their life, if only the laying of eggs or birth of young. Their skins have many glands and are often toxic. Reptiles, by contrast, have a dry watertight skin, usually protected by scales , that normally has few if any glan...

Halobacteria

... halobacteria are a family of archaea , found in water saturated or nearly saturated with salt. They are also called halophiles , though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments where large amounts of salt, moi...

Glucose

...oxidized to eventually form carbon dioxide and water , yielding energy, mostly in the form of ATP . It is also broken down from polysaccharides before use. Chemically joined together, glucose and fructose form sucrose . Starch , cellulose , and glycogen are common glucose polymers ( polysacch...

Fungus

...st their roots in absorption of nutrients and water . Contents showTocToggle("show","hide") ...shrooms are classified in the Basidiomycota. The water moulds , of which potato blight is the best known example, show a hyphal organization and were onc...

Fermentation

...er , known as grist , which is mixed with heated water in a vat called a "mash tun" for a process known as "mashing". During this process, natural enzymes within the malt break down much of the starch into sugars which play a vital part in the fermentation process. Mashing usually takes 1 to 2 ...

Extinction

...for limited resources. Vital resources including water and food can also be limited during habitat degradation, causing some species to become extinct. Predation, competition, and disease Coextinction Main article: Coextinction Effects Mass extinctions Main article: Mass extinctio...

Excretion

... should a person be in a situation of insufficient water and in danger of overheating due to lack of perspe...ink it (or salty ocean water), as it requires more water from the body to excrete the salt than is available in the fluid. Some sea birds are able to efficen...

Eukaryote

...gae Chromista Brown algae , diatoms , water moulds , etc. Alveolates Ciliates , Apicomplexa , dinoflagellates , etc. However, some protists are not closely related to any of these lines, and the relationships between the different supergroups remain almost entirely uncertain. I...

Bacterium

...of all organisms. They are ubiquitous in soil , water , and as symbionts of other organisms. Many pa... atmosphere. They apparently pioneered the use of water as (lithotrophic) electron source and were the first to use the photosynthetic water splitting app...