free radical


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free radical

n.
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.

free radical

n
(Chemistry) an atom or group of atoms containing at least one unpaired electron and existing for a brief period of time before reacting to produce a stable molecule. Sometimes shortened to: radical Compare group10

free′ rad′ical


n.
a molecular fragment that bears one or more unpaired electrons and is therefore highly reactive.
[1895–1900]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.free radical - an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule that 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"
atom - (physics and chemistry) the smallest component of an element having the chemical properties of the element
References in periodicals archive ?
We have turned this theory on its head by proving that free radical production increases during aging because free radicals actually combat -- not cause -- aging.
Once a free radical joins with an antioxidant, it is stable.
These thermodynamic properties can be used to predict a pecking order, or hierarchy, for free radical reactions.
When a free radical becomes oxidized, it turns into a pro-oxidant.
present 17 articles by Asian researchers working in free radical biology, gastroenterology, and hepatology who discuss the role of free radicals in digestive diseases such as pancreatitis, cancer, liver disease, hepatitis C, inflammatory bowel disease, drug-induced small intestinal injury, gastric mucosal injury, and infection, as well as the biology of free radicals, the role of biomarkers in monitoring the degree of disease and the design of new therapeutic strategies, and factors such as transition metal imbalance, lipid and glucose metabolic disturbance, mitochondria, oxidative stress and inflammation, and the interaction of gaseous molecules in producing free radicals.
Research approaches for explaining the effects of free radical exposure on protein structure are explored.
The content of this paper is to explore the effectiveness of tannins on the inhibition of free radicals and to discover the free radical scavenging abilities of tannins in unknown plant species.
Now, the free radicals formed roam throughout the body looking for the needed electron, until they get it by oxidizing the nearest molecule, which--now having an unpaired electron--becomes a free radical itself, starting a chain reaction that involves more free radicals, more instability and more damage resulting in the disruption of the living cell.
Now researchers report in the August 2005 Journal of Clinical Investigation that even before the immune system cranks up, NADPH oxidases in pollen itself generate a type of free radical known as reactive oxygen species (ROS), which interfere with cell signaling pathways and cause the immune system to overreact.
Some of the most common sources of free radical stress in the body come from smoking, chronic stress, and obesity.
Free radical molecules can exist on their own, but they are sometimes found within the structure of certain enzymes or proteins, which have either attracted them or, in some cases, produced them themselves.
A free radical is an atom or molecule that has at least one unpaired electron, causing it to be very chemically reactive.