Carbohydrate Chemistry – Vocabulary Flashcards

Vocabulary flashcards covering fundamental terms, structures, reactions, and classifications in carbohydrate chemistry to aid exam preparation.

Sucrose

A non-reducing disaccharide composed of glucose and fructose linked by an αβ-1,2 glycosidic bond; shows no mutarotation.

Hyaluronic Acid (Hyaluronan)

The only non-sulfated glycosaminoglycan (GAG); built from glucuronic acid and N-acetylglucosamine; acts as a lubricant and shock absorber in joints and vitreous humor.

Chondroitin Sulfate

A sulfated GAG of cartilage, tendons, and cornea made of D-glucuronate and N-acetylgalactosamine-4- or 6-sulfate.

Heparin

Highly sulfated intracellular GAG (mast cells) with anticoagulant activity; repeating units contain D-glucuronate sulfate and N-sulfo-D-glucosamine.

Glyceraldehyde

The simplest aldose (aldotriose); parent compound of all aldoses and possesses one chiral carbon.

Dihydroxyacetone (DHA)

The simplest ketose (ketotriose); parent compound of ketoses and has no chiral carbon.

Fructose

A 6-carbon ketose (hexulose); the sweetest natural sugar and major sugar in honey.

Inulin

A fructosan homopolysaccharide of fructose units; used to assess kidney function.

Cellulose

A β-1,4-linked glucosan that forms dietary fiber; aids stool formation and relieves constipation.

Starch

A glucosan homopolysaccharide (amylose + amylopectin) serving as plant glucose storage.

Glycogen

Animal storage glucosan with α-1,4 and α-1,6 branches; buffers blood glucose levels.

Dextran

A bacterial/yeast α-1,6 glucosan used clinically as a plasma expander.

Agar

A galactosan polysaccharide from red algae; used as solidifying agent in microbiological media.

Sorbitol (Glucitol)

Polyol formed by reduction of glucose; accumulates in diabetic cataract formation.

Mannitol

Polyol produced by reduction of mannose (and partly fructose); used as osmotic diuretic.

Osazone

Yellow needle-like crystals formed when reducing sugars react with excess phenylhydrazine.

Lactose

Reducing disaccharide of galactose + glucose joined by β-1,4 bond; milk sugar.

Maltose

Reducing disaccharide of two glucose units linked α-1,4; product of starch digestion.

Isomaltose

Disaccharide of two glucose units linked α-1,6; formed at starch branch points.

Lactulose

Semi-synthetic galactose-fructose disaccharide used as osmotic laxative and in portal encephalopathy.

Trehalose

Non-reducing glucose-glucose disaccharide with α,α-1,1 linkage; stabilizes proteins in organisms.

Ribose

A 5-carbon aldopentose; sugar component of RNA and certain nucleotides.

Ribulose

A 5-carbon ketopentose important in the pentose phosphate pathway and photosynthesis.

Glucuronic Acid

Product of glucose oxidation at the primary alcohol (C-6); important for detoxification conjugations.

Mucic Acid

Saccharic acid obtained by oxidation of both ends of galactose.

N-Acetylneuraminic Acid (Sialic Acid)

A 9-carbon amino sugar (nonose) derived from N-acetylmannosamine and pyruvate; terminal residue in glycoproteins.

N-Acetylgalactosamine (GalNAc)

Amino sugar component of chondroitin sulfate and blood group antigens.

Epimer

Two sugars that differ in configuration around a single specific carbon (e.g., glucose vs. galactose at C-4).

Enantiomer

Mirror-image stereoisomers that are non-superimposable (D- vs. L-glyceraldehyde).

Anomer

Isomers differing at the newly formed hemiacetal/hemiketal carbon (α vs. β) after sugar cyclization.

Chiral (Asymmetric) Carbon

A carbon atom attached to four different substituents, giving rise to optical activity.

Number of Stereoisomers (2ⁿ Rule)

For a molecule with n chiral carbons, possible stereoisomers = 2ⁿ (e.g., fructose with 3 chiral centers → 8 isomers).

Aldose

Monosaccharide with an aldehyde group at C-1 (e.g., glucose, glyceraldehyde).

Ketose

Monosaccharide with a keto group, usually at C-2 (e.g., fructose, dihydroxyacetone).

General Formula of Monosaccharides

(CH₂O)ₙ, where n ≥ 3.

Alpha-Beta 1,2 Linkage

Mixed glycosidic bond connecting α-D-glucose and β-D-fructose in sucrose.

Beta-1,4 Linkage

Glycosidic bond joining galactose to glucose in lactose or glucose units in cellulose.

Alpha-1,6 Linkage

Branching bond in glycogen and amylopectin; links glucose units in isomaltose.