1. Disaccharides
1.1. Lactose
1.1.1. Milk sugars
1.1.2. Galactose + Glucose
1.1.2.1. Requires Lactose to digest
1.1.2.2. β (1, 4) linkage
1.2. Maltose
1.2.1. Intermediate of starch hydrolysis
1.2.2. Glucose + Glucose
1.2.2.1. α (1, 4) linkage
1.3. Cellobiose
1.3.1. Degredation product of Cellulose
1.3.2. Glucose + Glucose
1.3.2.1. β (1, 4) linkage
1.4. Sucrose
1.4.1. Table sugar (cane or beet sugar)
1.4.2. α-Glucose (1, 2) + β-Fructose (1, 2) linkage
2. Monosaccharides
2.1. Glucose
2.1.1. Primary fuel for living cells
2.2. Fructose
2.2.1. Twice as sweet as glucose per gram
2.2.2. Energy source for sperm
2.2.2.1. High fructose corn syrup: made from pure corn syrup (glucose) and mixed by varying ratios with modified corn syrup.
2.3. Galactose
2.3.1. Used in synthesizing numerous biomolecules used by cells
2.3.2. Bodies can make it and utilize it
2.4. Derivatives:
2.4.1. Uronic acids
2.4.2. Amino sugars (hydroxyl group attached)
2.4.3. Deoxy sugars
2.4.3.1. Used in DNA
2.4.3.2. Fructose is "6-deoxygalactose"
3. Polysaccharides
3.1. Homoglycans
3.1.1. Polysaccharides have No fixed molecular weight
3.1.2. In a "well=fed" state, the liver synthesizes glycogen until blood sugar levels reach proper levels.
3.1.3. Starch
3.1.3.1. Energy reservoir in plant cells
3.1.3.2. Energy source in human diet (potatoes, rice, wheat)
3.1.3.3. Amylose + Amylopectin
3.1.3.3.1. Amylose = long, unbranched chains of D-glucose residues that are linked with α (1, 4) linkage.
3.1.3.3.2. Amylopectin = branched polymer containing both α (1, 4) and α (1, 6) linkage.
3.1.4. Glycogen
3.1.4.1. Carbohydrate storage molecule in vertebrates
3.1.4.2. Greatest abundance found in liver
3.1.4.3. Similar in structure to amylopectin, but with more branch points.
3.1.4.4. Molecule is more compact than other polysaccharides and takes up little space.
3.1.5. Cellulose
3.1.5.1. Polymer with D-glucopyranose linked by β (1, 4) linkage.
3.1.5.2. Most important structural polysaccharide of plants.
3.2. Heteroglycans
3.2.1. High-molecular-weight polymer with more than one monosaccharide
3.2.2. N- and O- Glycans
3.2.2.1. N-Glycans: oligosaccharides linked via β-glycosidic bond between core N-acetylglucosamine carbon and side chain amide nitrogen
3.2.2.1.1. N-acetylglucosamine: the most commonly observed sugar among N-glycans
3.2.2.1.2. Not all N-glycans have the same core structure
3.2.2.2. O-Glycans: oligosaccharides have a disaccharide core of galactosyl-β-(1,3)-N-acetylgalactosamine linked to protein via an α-glycosidic bond to the hydroxyl oxygen of serine or threonine residues.
4. Glyconjugates
4.1. Compounds from covalent linkages of carbohydrates to both proteins and lipids
4.2. Proteoglycans
4.2.1. Present on the cell surface or secreted into the extracellular matrix
4.2.2. Made of GAGs linked to proteins with N- and O-glycosidic linkages.
4.2.3. GAG backbone: hyaluronic acid
4.2.4. Examples:
4.2.4.1. Syndecans: includes a transmembrane core protein
4.2.4.2. Glypicans: linked to membrane via GPI anchors
4.2.4.3. Aggrecan: found in cartilage; combination of chondroitin sulfate and keratan sulfate attached to a core
4.2.5. Multifunctional proteins: signaling, structural (compressive stiffness)
4.3. Gycoproteins
4.3.1. Proteins that are linked through N- or O- linkages to carbohydrates (i.e: N- or O-glycans)
4.3.2. Carb content ranges from 1-85%
4.3.3. Carbs involved: monosaccharides, disaccharides, several oligosaccharides
4.3.4. N-linked carbohydrate chains formed initially and then added to protein during synthesis (OCCURS IN THE ER)
4.3.4.1. O-linked chains are built directly on protein in Golgi
4.3.5. Examples:
4.3.5.1. Immunoglobulin (antibodies)
4.3.5.2. Hormones: HCG, FSH (indicates pregnancy)
4.3.5.3. Metal transport proteins: transferrin and ceruloplasmin
4.3.5.4. Membrane protein: Na+ -K+-ATPase (Na+-K+ pump)
4.3.5.5. ABO blood group system