Selasa, 20 Januari 2009

hidroxyl

Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. The neutral form is a hydroxyl radical and the hydroxyl anion is called a hydroxide. When the oxygen atom is linked to a larger molecule the hydroxyl group is a functional group (HO¯ or ¯OH) . Hydroxide (OH anion) is a polyatomic ion with a charge of negative one. Hydroxide anion is a base and is used to make solutions or compounds basic.

[edit] Hydroxyl group

The term hydroxyl group is used to describe the functional group –OH when it is a substituent in an organic compound. Organic molecules containing a hydroxyl group are known as alcohols (the simplest of which have the formula CnH2n+1–OH).

[edit] Hydroxyl radical

Main article: Hydroxyl radical

The hydroxyl radical, ·OH, is the neutral form of the hydroxide ion. Hydroxyl radicals are highly reactive and, as a consequence, short-lived; however, they form an important part of radical chemistry.

Hydroxyl free radicals cause oxidative cells, particularly erythrocytes (or red blood cells). These free radicals cause damage to DNA, lipids, and proteins.[citation needed] Glucose-6 phosphate dehydroganase (G6PD) is an enzyme the body produces to destroy OH-, before it starts damaging the cells. People with G6PD deficiency are protected against malaria because the plasmodium (the parasites that cause malaria) cannot survive in the damaged blood cells.[citation needed] On the other hand, people with G6PD deficiency are prone to jaundice and kidney disease.

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