D-glucose

Glucose is a primary source of energy for the <a href="http://en.wikipedia.org/wiki/Brain" title="Brain" >brain</a>, and hence its availability influences <a href="http://en.wikipedia.org/wiki/Psychological" title="Psychological" class="mw-redirect" >psychological</a> processes.

When <a href="http://en.wikipedia.org/wiki/Hypoglycaemia" title="Hypoglycaemia" class="mw-redirect" >glucose is low</a>, psychological processes requiring mental effort

(e.g., <a href="http://en.wikipedia.org/wiki/Self-control" title="Self-control" class="mw-redirect" >self-control</a>, effortful decision-making) are impaired.<a href="http://en.wikipedia.org/wiki/Dextrose#cite_note-4" >[5]</a><a href="http://en.wikipedia.org/wiki/Dextrose#cite_note-5" >[6]</a><a href="http://en.wikipedia.org/wiki/Dextrose#cite_note-6" >[7]</a><a href="http://en.wikipedia.org/wiki/Dextrose#cite_note-7" >[8]</a>

Glucose (<a href="http://en.wikipedia.org/wiki/Wikipedia:IPA_for_English" title="Wikipedia:IPA for English" >/</a><a href="http://en.wikipedia.org/wiki/Wikipedia:IPA_for_English#Key" title="Wikipedia:IPA for English" >ˈɡluːkoʊs</a><a href="http://en.wikipedia.org/wiki/Wikipedia:IPA_for_English" title="Wikipedia:IPA for English" >/</a> or <a href="http://en.wikipedia.org/wiki/Wikipedia:IPA_for_English" title="Wikipedia:IPA for English" >/</a><a href="http://en.wikipedia.org/wiki/Wikipedia:IPA_for_English#Key" title="Wikipedia:IPA for English" >-koʊz</a><a href="http://en.wikipedia.org/wiki/Wikipedia:IPA_for_English" title="Wikipedia:IPA for English" >/</a>; C6H12O6, also known as D-glucose, dextrose, or grape sugar) is a simple <a href="http://en.wikipedia.org/wiki/Sugar" title="Sugar" >sugar</a> (<a href="http://en.wikipedia.org/wiki/Monosaccharide" title="Monosaccharide" >monosaccharide</a>) and an important <a href="http://en.wikipedia.org/wiki/Carbohydrate" title="Carbohydrate" >carbohydrate</a> in <a href="http://en.wikipedia.org/wiki/Biology" title="Biology" >biology</a>.

<a href="http://en.wikipedia.org/wiki/Cell_(biology)" title="Cell (biology)" >Cells</a> use it as the primary source of energy<a href="http://en.wikipedia.org/wiki/D-glucose#cite_note-0" >[1]</a> and a metabolic intermediate. Glucose is one of the main products of <a href="http://en.wikipedia.org/wiki/Photosynthesis" title="Photosynthesis" >photosynthesis</a> and fuels for <a href="http://en.wikipedia.org/wiki/Cellular_respiration" title="Cellular respiration" >cellular respiration</a>. Glucose exists in several different molecular structures, but all of these structures can be divided into two families of mirror-images (<a href="http://en.wikipedia.org/wiki/Stereoisomer" title="Stereoisomer" class="mw-redirect" >stereoisomers</a>).

Only one set of these isomers exists in nature, those derived from the "<a href="http://en.wikipedia.org/wiki/Chirality(chemistry)#By_configuration:D-_and_L-" title="Chirality (chemistry)" >right-handed form</a>" of glucose, denoted D-glucose. D-glucose is sometimes referred to as dextrose, although the use of this name is strongly discouraged. The term dextrose is derived from <a href="http://en.wikipedia.org/wiki/Dextrorotatory" title="Dextrorotatory" class="mw-redirect" >dextrorotatory</a> glucose.<a href="http://en.wikipedia.org/wiki/D-glucose#cite_note-1" >[2]</a>

This name is therefore confusing when applied to the enantiomer, which rotates light the opposite direction. <a href="http://en.wikipedia.org/wiki/Starch" title="Starch" >Starch</a> and <a href="http://en.wikipedia.org/wiki/Cellulose" title="Cellulose" >cellulose</a> are <a href="http://en.wikipedia.org/wiki/Polymer" title="Polymer" >polymers</a> derived from the dehydration of D-glucose.

The other stereoisomer, called <a href="http://en.wikipedia.org/wiki/L-glucose" title="L-glucose" class="mw-redirect" >L-glucose</a>, is hardly ever found in nature.

The name "glucose" comes from the <a href="http://en.wikipedia.org/wiki/Greek_language" title="Greek language" >Greek</a> word glukus (γλυκύς), meaning "sweet", and is the preferred name. The suffix "<a href="http://en.wikipedia.org/wiki/-ose" title="-ose" >-ose</a>" denotes a sugar.

The reason that glucose, and not another <a href="http://en.wikipedia.org/wiki/Monosaccharide" title="Monosaccharide" >monosaccharide</a> such as <a href="http://en.wikipedia.org/wiki/Fructose" title="Fructose" >fructose</a>, is so widely used in organisms is not clearly understood.

One reason might be that glucose has a lower tendency, relative to other <a href="http://en.wikipedia.org/wiki/Hexose" title="Hexose" >hexose</a> sugars, to react non-specifically with the <a href="http://en.wikipedia.org/wiki/Amine" title="Amine" >amino</a> groups of <a href="http://en.wikipedia.org/wiki/Protein" title="Protein" >proteins</a>.

This reaction (<a href="http://en.wikipedia.org/wiki/Glycation" title="Glycation" >glycation</a>) reduces or destroys the function of many <a href="http://en.wikipedia.org/wiki/Enzyme" title="Enzyme" >enzymes</a>.

The low rate of <a href="http://en.wikipedia.org/wiki/Glycation" title="Glycation" >glycation</a> is due to glucose's preference for the less reactive cyclic <a href="http://en.wikipedia.org/wiki/Isomer" title="Isomer" >isomer</a>.

Nevertheless, many of the long-term complications of <a href="http://en.wikipedia.org/wiki/Diabetes_mellitus" title="Diabetes mellitus" >diabetes</a> (e.g., <a href="http://en.wikipedia.org/wiki/Blindness" title="Blindness" >blindness</a>, <a href="http://en.wikipedia.org/wiki/Renal_failure" title="Renal failure" >renal failure</a>, and <a href="http://en.wikipedia.org/wiki/Peripheral_neuropathy" title="Peripheral neuropathy" >peripheral neuropathy</a>) are probably due to the glycation of proteins or lipids.<a href="http://en.wikipedia.org/wiki/D-glucose#cite_note-2" >[3]</a>

In contrast, <a href="http://en.wikipedia.org/wiki/Enzyme" title="Enzyme" >enzyme</a>-regulated addition of glucose to proteins by <a href="http://en.wikipedia.org/wiki/Glycosylation" title="Glycosylation" >glycosylation</a> is often essential to their function.[<a href="http://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed" >citation needed</a>]