CARBOHYDRATES

Carbohydrates

Biomolecules primarily composed of carbon, hydrogen, and oxygen, known for their role as energy sources.

Monosaccharides

Simple sugars that cannot be hydrolyzed into simpler carbohydrates; examples include glucose and fructose.

Disaccharides

Carbohydrates formed from two monosaccharide units linked by a glycosidic bond, such as sucrose and maltose.

Polysaccharides

Carbohydrates composed of long chains of monosaccharide units; examples include starch, cellulose, and glycogen.

Glycosidic bond

A type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate.

Reducing sugar

Sugars that can be oxidized due to the presence of a free aldehyde or ketone group, capable of forming a silver mirror in the Tollen's test.

Non-reducing sugar

Sugars lacking an available aldehyde or ketone group due to formation in a glycosidic bond, thus do not react in the Tollen’s test.

Alpha and beta forms of sugars

Isomers that differ in the orientation of the hydroxyl group on the anomeric carbon; α is trans to CH2OH and β is cis.

Amylose

A type of starch consisting of long, unbranched chains of α-D-glucose units.

Cellulose

A structural polysaccharide made of β-D-glucose units linked by β-1,4-glycosidic bonds, found in plant cell walls.

Glycoproteins

Proteins that have carbohydrate groups attached to them, important for cell-cell recognition and signaling.

Epimer

Stereoisomers that differ at only one of their multiple chiral centers.

Hemicellulose

A variable group of polysaccharides that are present in plant cell walls alongside cellulose.

Glycolipids

Lipids with carbohydrate attached, important for cell recognition and membrane stability.

Amino sugars

Sugars that have an amino group (-NH2) replacing one of the hydroxyl groups, such as N-acetylglucosamine.

Nucleotide

The basic building block of nucleic acids, comprised of a nitrogenous base, a sugar, and a phosphate group.

Starch vs. Cellulose

Starch is a storage polysaccharide with α-1,4 linkages, while cellulose is a structural polysaccharide with β-1,4 linkages.

Anomeric carbon

The carbon atom in a sugar that is derived from the carbonyl group and becomes a new stereocenter when the sugar cyclizes.

Tollen's test

A qualitative test to detect reducing sugars, based on their ability to reduce silver ions to metallic silver.

Benedict’s test

A test that identifies reducing sugars by measuring the color change of copper ions in an alkaline solution.