BIOLOGY 1A03 Lecture Notes - Lecture 3: Glycoprotein, Pentose, Aldehyde

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Daniel Yang

Document Summary

Transport of energy source - sucrose (plants), lactose (milk) Cell surface signals - cell communication and cell-cell recognition. For galactose to be used by cell, must rst be converted to glucose via enzyme-catalyzed reactions. 5. 3 sugars exist in linear and ring forms - note that glucose in aqueous solutions forms ring structures. Glucose hydroxyl group is below the plane of the ring. Glucose hydroxyl group is above the plane of the ring. Are double sugars that consist of two monosaccharides, which are joined a condensation (dehydration) reaction. Glucose + glucose -> maltose the hydroxyl groups from 1-carbon and 4-carbon react to form an -1,4 glycosidic linkage and water. Glucose + fructose -> sucrose hydroxyl groups from the 1-carbon and 4-carbon react (with glucose ipped upside down) to produce a -1,4-glycosidic linkage and water. Symptoms : diarrhea, stomach pain, bloating, gas after consuming lactose. Adults do not produce lactase (enzyme) which splits lactose into glucose and galactose.