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تعريف free radical في الإنجليزية الإنجليزية القاموس.
any molecule, ion or atom that has one or more unpaired electrons; they are generally highly reactive and often only occur as transient species
A molecule that can cause oxidative damage to a cell or tissue Antioxidants are used to destroy free radicals
A molecule containing an unpaired electron, typically highly unstable and reactive Free radicals can damage the molecular machinery of biological systems, leading to cross-linking and mutation
Any molecular fragment containing an unpaired electron Such fragments are often very reactive, reacting with nearby molecules as fast as they encounter them Radicals formed on the surface of catalysts may be much more stable and able to undergo more selective chemistry This is due to the stabilizing influence of the surface
an unstable, destructive oxygen molecule created as a normal byproduct of metabolism
short-lived form of compounds that exist with an unpaired electron in the outer electron shell; to complete the electron pair the compound seeks an additional electron from another molecule often from electron dense areas of the cell such as the nucleus or the cell membrane
An atom or group of atoms broken away from a stable compound by application of external energy, and, although containing unpaired electrons, remaining free for transitory or longer periods
an atom or group of atoms that has at least one unpaired electron Because another element can easily pick up this free electron and cause a chemical reaction, these free radicals can effect dramatic and destructive changes in the body
A molecule with an unpaired electron In the body, free radicals are generated by both enzymatic and chemical reactions, including the metabolism of fats Free radicals are believed to be involved in extensive damage to the body, including aging cancer, heart disease and arthritis
a molecule that contains at least one unpaired electron Free radicals are highly reactive and bind with other molecules, thus disrupting normal cellular processes and causing cellular damage (oxidative stress)
a molecule that contains at least one unpaired electron Free radicals (reactive oxygen species) are a byproduct of normal metabolism They are highly reactive and bind with electrons from other molecules, potentially initiating chain reactions as successive molecules lose and gain electrons The robbing of electrons by free radicals can disrupt normal cellular processes and cause cellular damage (oxidative stress) See also antioxidant, oxidation
a molecule with an odd, unpaired electron, which is highly unstable and can have distructive effects
a highly chemically reactive atom, molecule or molecular fragment with a free or unpaired electron Free radicals are produced in many different ways such as, normal metabolic processes, ultraviolet radiation from the sun, nuclear radiation and the breakdown in the body of spoiled fats Free radicals have been implicated in aging, cancer, cardiovascular disease and other kinds of damage to the body, (see antioxidants)
A destructive fragment of oxygen produced as a by-product when cells use oxygen to burn fat
molecules containing an odd number of electrons resulting in an open bond or half bond, making them highly reactive and as a result, potentially destructive
an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule than has lost an electron and will stabilize itself by stealing an electron from a nearby molecule; "in the body free radicals are high-energy particles that ricochet wildly and damage cells
A chemically active, charged atom or complex of atoms containing an excess or deficient number of electrons Radicals seek to transfer electrons from or to other atomic complexes in order to achieve a more stable configuration This process can damage the large molecules within cells See Oxidation
A highly reactive chemical species carrying no charge and having a single unpaired electron in an orbital
Free radicals are aggressive atoms or molecules that cause permanent damage when they react with cell components They are highly reactive because they have unpaired electrons Free radicals attack the nearest stable molecule and "steal" its electron, thereby oxidizing the molecule Research shows that free radicals are associated with premature aging and the degenerative diseases
Free radicals are atoms that contain one or more unpaired electrons. Free radicals are believed to be a cause of ageing, heart disease, and some cancers. An atom or group of atoms that has at least one unpaired electron and is therefore unstable and highly reactive. In animal tissues, free radicals can damage cells and are believed to accelerate the progression of cancer, cardiovascular disease, and age-related diseases. an atom or group of atoms with at least one free electron, which combines with other atoms very easily. or radical Molecule containing at least one unpaired electron. Most molecules contain even numbers of electrons, and their covalent bonds normally consist of shared electron pairs. Cleavage of such bonds produces two separate free radicals, each with an unpaired electron (in addition to any paired electrons). They may be electrically charged or neutral and are highly reactive and usually short-lived. They combine with one another or with atoms that have unpaired electrons. In reactions with intact molecules, they abstract a part to complete their own electronic structure, generating new radicals that go on to react with other molecules. Such chain reactions are particularly important in decomposition of substances at high temperatures and in polymerization. In the human body, oxidized (see oxidation-reduction) free radicals can damage tissues. Antioxidant nutrients (e.g., vitamin C, vitamin E, selenium) may reduce these effects. Heat, ultraviolet radiation, and ionizing radiation (see radiation injury) all generate free radicals. They are magnetic, so their properties can be studied with such techniques as magnetic susceptibility and electron paramagnetic resonance measurements
An unstable and highly reactive molecule, bearing an atom with an unpaired electron, that nonspecifically reacts with a variety of organic structures such as DNA The interaction of ionizing radiation with water can generate free radicals in the form of hydroxyl and hydroperoxyl groups that are potent oxidizing agents
This is a substance which can bring about negative changes in the body as a result of its oxidizing effects Some changes include: hardening of the arteries and onset of certain cancers
Highly reactive substances often formed naturally by the interaction of oxygen with polyunsaturated fatty acids Free radicals possess the ability to interact with important components of tissues such as proteins and DNA and have been implicated in aging and many disease states
Highly toxic molecules capable of causing damage in brain and other tissue Free radicals are common by-products of normal chemical reactions occurring in the body
Molecules with unpaired electrons that react readily with other molecules Oxygen-free radicals, produced during metabolism, damage cells and may be responsible for aging in tissues and organs
These are atoms or molecules with an unpaired electron and are highly reactive They are produced by the environment; sunlight, heat and radiation Free radicals can damage the skin by attacking cellular membranes
Highly reactive or unstable molecules and atoms that cause aging and degenerative diseases These free radicals often result from ozone, cigarette smoke, herbicides and pesticides, solvents, petrochemicals, drugs, sunshine, X-rays and other foreign body substances
oxygen molecules with single missing electrons, which cause cellular damage by taking electrons from molecules in healthy cells This process is called oxidation
Atoms or molecules with an unpaired electron Formation of free radicals is a normal oxidation process in foods and are formed during food treatments such as toasting, frying, freeze drying, and irradiation They are generally very reactive, unstable structures that continuously react with substances to form stable products
Unstable molecules, produced naturally by the body, which, if not neutralized by antioxidants, can damage or destroy DNA in cells In excess (over stimulated by pollutants such as radiation, UV light, car fumes, and cigarette smoke), they are thought to be one of the main culprits responsible for many diseases, including cancer and arthritis
Atoms or groups of atoms that have an unpaired electron in their outer orbit, causing them to be unstable and highly reactive Free radicals in the form of toxic metabolic by-products are thought to be a contributory cause of PD
Every second that goes by, billions of free radicals are working in our bodies They have a potentially deadly goal of altering our generic material and destroying our cells Many every day complaints and diseases have been implicated with free radicals
Atomic or molecular species with unpaired electrons or an otherwise open shell configuration, usually very reactive Specific to atmospheric chemistry, free radicals are: short-lived, highly reactive, intermediate species produced by dissociation of the source molecules by solar ultraviolet radiation or by reactions with other stratospheric constituents Free radicals are the key to intermediate species in many important stratospheric chain reactions in which an ozone molecule is destroyed and the radical is regenerated See ozone
Highly reactive oxygen by-products created by normal cell metabolism Free radicals lack electrons and try to steal them from other molecules, damaging them This damage is thought to be a fundamental cause of many degenerative diseases and the aging process If free radicals attack the molecules involved in normal cellular reproduction, cells may become cancerous Free radicals can damage the molecules responsible for moving cholesterol through the bloodstream resulting in the build up of plaque in the arteries