Nplex Biochem Carbs

OVERVIEW

A.) Types:

MONOSACCHARIDES

Biochemistry ~ Carbohydrates - compounds that contain at least 3 carbon atoms + hydroxyl groups and usually an aldehyde or ketone group glucose = major product of digestion (some galactose and fructose also produced) = major fuel source oxidized by cells for energy = stored as glycogen or triacylglycerols after a meal = converted to glucose 6-phosphate when enters cell, then G6P enters glycolysis ( NADH & ATP) or pentose phosphate pathway ( NADPH) Glycogen: - major storage form of carbs in animals - largest stores in mm and LV - mm glycogen used to generate ATP for mm contraction - LV glycogen used to maintain blood glucose during fasting or exercise - LV produces glucose from glycogenolysis & gluconeogenesis - cannot be reduced or hydrolyzed into smaller or simpler sugars - produced by the breakdown of dietary carbohydrates - major energy source for the body - usually found as D-series vs its enantiomer (mirror image) L-series Structure: (formula = CH2O)n - all of the above are hexose (6carbon) monosaccharides) - mainly ring structures where aldehyde or ketone group reacts with hydroxyl group - structural formula is C6H12O6 (differ in the position of the =O) - epimers: stereoisomers that differ in the position of the hydroxyl group at only 1 assymetric carbon - aldose or ketose depending on aldehyde or ketone as most oxidized functional group

Fructose glucose - glucose, - fructose, - galactose, - mannose (all isomers of eachother)

Glucose: - most important & abundant - body uses glucose to synthesize other carbs - major source of fuel in the body Fructose: can be converted to glucose - a ketose (all others = aldoses) - forms furanose rings vs. pyranose rings - metabolized mainly in the liver  glyceraldehydes 3-P (intermediate of glycolysis) - can be produced from sorbitol (generated from glucose) Galactose: - converted to glucose when taken into the body Mannose: - constituent found in the glycoproteins of plant gums

DI-SACCHARIDE: - sucrose, lactose, maltose, isomaltose

- 2 monosaccharides covalently bonded via glycosidic attachment - glycosidic attachment can also bond carbs to purines, pyrimidines, aromatic rings, lipids etc… - bond is between anomeric carbon of one molecule & different C of 2nd molecule Sucrose: (glucose + fructose)  table sugar - both use anomeric carbon  ring can’t open  NO alpha or beta ring structure Lactose: (glucose β-1,4 linked to galactose) - milk sugar - galactose uses anomeric carbon - glucose does not use anomeric C, so can open and form alpha or beta ring structure Maltose: (glucose + glucose) - one glucose uses anomeric carbon - other glucose does not use anomeric C, so can open and form alpha or beta ring structure

POLYSACCHARIDE: Amylase, amylopectin, glycogen, inulin

Isomaltose: (glucose + glucose) – like maltose - bound by alpha-1,6 glycosidic linkage (vs. alpha-1,4 in maltose) >6 monosaccharides - can be linear or branched - major role = storage of monosaccharides (starch, amylase, amylopectin) - major role = structural support (cellulose, chitin) Amylose: ( lots of glucose molecules) - non branching (unbranched) starch of alpha-1,4 glycosidic linkages - spiraling helical shape or coil - abundant in many plants Amylopectin: - branching starch of alpha-1,4 glycosidic linkages - branch points = alpha- 1.6 linkages - branch points at about every 24- 30 glucose residues (not how described in H.M. pg 125) Glycogen:

1