(dextrose, grape sugar) An aldohexose sugar. In solution it forms a six-membered * pyranose ring. Glucose is the major fuel source of nearly all organisms and the basic substrate from which starch, cellulose, sucrose, and other carbohydrates are synthesized. Glucose is synthesized by several routes; de novo synthesis from carbon dioxide is via the * Calvin cycle, but synthesis from fatty acids via acetyl CoA and the * glyoxylate cycle is also a major route in some cells (e.g. germinating oil-bearing seeds). It can be oxidized through * glycolysis and the * TCA cycle. Synthetic pathways from glucose involve activation, by phosphorylation or by formation of a nucleotide diphosphate sugar. |
