BIOL 112 Lecture Notes - Lecture 6: Glycosidic Bond, Cellobiose, Chemical Formula

• School: McGill University
• Department: Biology
• Course: BIOL 112
• Professor: Joseph Dent, Frieder Schock

Document Summary

Jan 23 2019: lecture 6: sugars and lipids. Hundreds to hundreds of thousands of monosaccharides. Number carbon atoms from one side to other through longest chain. Exactly same molecular formula but different structure. Many times a group is attached to a different carbon atom. Optical isomer (stereoisomer) is a group attached in a different way to the same carbon atom. Need 4 different groups attached to the carbon atom. Glucose assumes a ring form once in water. As soon as ring is closed, alpha and beta isomers are formed. The shape becomes fixed as soon as glycosidic linkage is formed to make a disaccharide. Happens between carbon 1 (carbonyl group) covalent bonded to and of the hydroxyl groups. 11 different possible disaccharides from linking together. Alpha 1-4 and beta 1-4 are the only important ones. Carbon 1 links with hydroxyl on carbon 4. Important because these reactions are catalyzed by certain enzymes.