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free radical

free radical

8 5.1
A small unstable atom or molecule that can damage body cells by reacting with them
  • noun
  • /fri ˈrædɪkəl/
  • Specialized
translation icon : radical libre
  • We also measured free radical production in the retina to determine the oxidative stress level.
  • oxygen free radicals
  • free radical formation
  • free radical injury

So hydrogen is one of the great antioxidants, stabilizers of free radicals in nature.

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Examples

  • Meanwhile, smoking increases LDL buildup, perhaps by unleashing unstable free radical molecules that damage lipids and vessel walls.

  • So that's why things like antioxidants help to scavenge those free radicals and eliminate them so that they don't induce that DNA damage.

  • During normal body processes, free radicals are produced that have the potential to cause cancer and cell damage.

    Academic text (2012)
  • And free radicals in biology are both good and bad.

  • In large doses, iron directly damages cells by creating free radicals that cause injury to the cell.

    Academic text (2007)
  • Vitamin C and vitamin E can handle one free radical at a time and neutralize it.

    Blog text (6)
  • Normal byproducts of metabolism, called oxygen free radicals, also cause damage.

    Academic text (2003)
  • The vitamin and chemical scavengers would deal with the free radicals before they could cause any irreversible damage.

    Fiction book (1992)
  • Your liver converts ethanol to aldehydes, which produce free radicals that damage proteins in your liver.

    Blog text (18)
  • During normal body processes, free radicals are produced that have the potential to cause cancer and cell damage.

Synonyms

radical
vsfree radical
  • Specialized
9 8.1

A group of atoms that reacts quickly with other molecules

is commonly used for similar reactive molecules that damage cells in the body
hydroxyl radical
vsfree radical
  • Specialized
8.0

A small chemical part made of one oxygen and one hydrogen atom that reacts quickly

is a general term used especially for reactive molecules that harm body cells
peroxyl
vsfree radical
  • Specialized
9.9

A group of two oxygen atoms in a molecule that reacts easily and can damage cells

is used broadly for reactive species that can cause cell damage in organisms
methyl radical
vsfree radical
  • Specialized
7.0

A very active group of one carbon and three hydrogen atoms with formula CH3, formed when methane loses one hydrogen

is used mainly for reactive biological molecules rather than simple chemical intermediates
benzyl radical
vsfree radical
  • Specialized
8.7

A small chemical group formed when toluene loses one hydrogen atom from its methyl part

is used more for reactive biological molecules rather than specific organic fragments

Surface Forms

free radical singular
free radicals plural

Morphology

free + radical

The noun is a straightforward adjective + noun composition: 'free' (not bound) modifies 'radical' (a reactive chemical species), so the phrase literally denotes a radical that is not bound. Although the term is technical, its meaning follows normal compositional logic and would be predictable to a learner who knows both constituent senses.

Etymology

The term free radical comes from a simple chemistry image: a radical is a small group of atoms and when it is free it has a lonely, moving electron. That lonely electron makes it grab or change other molecules, so free radicals are quick to react and can 'harm' cells, which is why the name is used for these tiny, damaging particles.