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Amylose A is a parallel double-helix of linear chains of glucose. Amylose is made up of α(1→4) bound glucose molecules. The carbon atoms on glucose are numbered, starting at the aldehyde (C=O) carbon, so, in amylose, the 1-carbon on one glucose molecule is linked to the 4-carbon on the next glucose molecule (α(1→4) bonds). [3]
DNA molecules contain 5-membered carbon rings called deoxyriboses that are directly attached to two phosphate groups and a nucleobase that contains amino groups. The nitrogen atoms from the amino group in the nucleotides are covalently linked to the anomeric carbon of the ribose sugar structure through an N-glycosidic bond. Occasionally, the ...
Fischer glycosidation refers to the synthesis of glycosides by the reaction of unprotected monosaccharides with alcohols (usually as solvent) in the presence of a strong acid catalyst. The Koenigs-Knorr reaction is the condensation of glycosyl halides and alcohols in the presence of metal salts such as silver carbonate or mercuric oxide .
Conversely, plants undergo the Calvin Cycle to photosynthesize glucose-3-phosphate from CO 2 and H 2 O in the presence of light; the phosphate is quickly hydrolyzed into glucose. [12] Glucose to Glycogen Pathway. Digestion of complex carbohydrates allows glucose molecules to be re-polymerized into a form that is recognized by enzymes. [12]
Starch (a polymer of glucose) is used as a storage polysaccharide in plants, being found in the form of both amylose and the branched amylopectin. In animals, the structurally similar glucose polymer is the more densely branched glycogen, sometimes called "animal starch". Glycogen's properties allow it to be metabolized more quickly, which ...
The two glucose units are in the pyranose form and are joined by an O-glycosidic bond, with the first carbon (C 1) of the first glucose linked to the fourth carbon (C 4) of the second glucose, indicated as (1→4). The link is characterized as α because the glycosidic bond to the anomeric carbon (C 1) is in the opposite plane from the CH
In sucrose, the monomers glucose and fructose are linked via an ether bond between C1 on the glucosyl subunit and C2 on the fructosyl unit. The bond is called a glycosidic linkage. Glucose exists predominantly as a mixture of α and β "pyranose" anomers, but sucrose has only the α form.
If the glucose chain consists of three or fewer molecules, BAM cannot release maltose. A second enzyme, disproportionating enzyme-1 (DPE1), combines two maltotriose molecules. From this chain, a glucose molecule is released. Now, BAM can release another maltose molecule from the remaining chain. This cycle repeats until starch is fully degraded.