Reactions of Monosaccharides

Vocabulary-style flashcards covering key concepts from the notes on monosaccharide reactions (oxidation, reduction, glycoside formation, phosphate esters, and amino sugars).

Aldose

A sugar that contains an aldehyde group at the terminal carbon.

Aldonic acid

Product formed when the aldehyde end of an aldose is oxidized by weak oxidizing agents.

Tollens solution

A weak oxidizing reagent that oxidizes the aldehyde end of an aldose to an aldonic acid and reduces Ag+ to Ag.

Benedict’s solution

A weak oxidizing reagent that oxidizes the aldehyde end of an aldose to an aldonic acid and reduces Cu2+ to Cu+, indicated by a red precipitate when glucose is present.

Reducing sugar

A sugar (typically an aldose) that can act as a reducing agent; ketoses can also act as reducing sugars under basic conditions after isomerization.

Lobry de Bruyn–Van Ekenstein transformation

Base-catalyzed isomerization that can convert ketoses to aldoses (and vice versa), enabling ketoses to act as reducing sugars.

Urine glucose test

Testing for the presence of glucose in urine, used as a diagnostic indicator for diabetes.

Aldaric acid

A dicarboxylic acid produced when a strong oxidizing agent oxidizes both ends of a monosaccharide.

Aldaric acids

Plural term for dicarboxylic acids formed from monosaccharides by strong oxidation.

Alduronic acid

Product of enzymatic oxidation at the primary alcohol end of an aldose, without oxidizing the aldehyde group.

Enzymatic oxidation

Oxidation of a monosaccharide in biological systems by enzymes, can yield alduronic acids.

D-Glucitol (sorbitol)

Sugar alcohol formed by reduction of glucose; used as a moisturizing agent and sweetener; linked to cataract formation when accumulated in the lens.

Alditol

Sugar alcohols obtained by reducing aldoses or ketoses.

Erythritol

An alditol commonly found in foods; a sugar alcohol.

D-Mannitol

An alditol used as a sweetener and in medical applications.

Xylitol

An alditol used as a sugar substitute in chewing gums and confections.

Glycoside

An acetal formed from a cyclic monosaccharide by replacing the hemiacetal OH with an OR group; exists in alpha and beta forms.

Glucoside

A glycoside derived from glucose.

Galactoside

A glycoside derived from galactose.

Phosphate ester formation

Reaction of monosaccharide hydroxyl groups with phosphoric acid to form phosphate esters, common in metabolism.

Phosphate ester

An ester formed between phosphate and a sugar hydroxyl; stable in water and important in carbohydrate metabolism.

Phosphate esters of glucose

Glucose molecules bearing phosphate esters; play key roles in carbohydrate metabolism.

Amino sugar

A monosaccharide in which one hydroxyl group (often at C-2) is replaced by an amino group; many have N-acetyl derivatives.

N-acetyl derivatives

Acetylated amino sugars commonly found in polysaccharides and as RBC markers.

Chitin

A polysaccharide built from amino sugars (e.g., N-acetylglucosamine), found in exoskeletons and fungal cell walls.

Hyaluronic acid

A glycosaminoglycan composed of amino sugars; an important component of connective tissue.

Red blood cell markers

Biochemical markers on red blood cells that include amino sugars and their derivatives.