Chapter 7 definitions

Glycogen

A branched homopolysaccharide of glucose that stores fuel in animals

Cellulose

A fibrous, tough, water-insoluble substance serves in a structural role in cell walls of plants structure: glucose in Beta 1->4 glycosidic bonds, no branching,

Chitin

A linear homopolysaccharide composed of N-acetylglucosamine residues; Beta 1-4 linkage

Starch

A mixture of two homopolysaccharides, amylose and amylopectin, which stores fuel in plants.

Enantiomers

A molecule which contains one chiral center and therefore has two different optical centers

Reducing sugar

A sugar in which the anomeric carbon is not involved in a glycosidic linkage and can therefore undergo oxidation

Glycans

Another word for polysaccharides

Dextrans

Bacterial and yeast polysaccharides

lactose

Beta 1--> 4 alpha; still reducing

example of epimer between glucose and mannose

C-2 epimers

Anomeric isomers

Carbonyl carbon

Glycoconjugates

Complex carbohydrate polymers covalently attached to proteins or lipids

Oligosaccharides

Consist of short chains or monosaccharide units or residues joined by glycosidic bonds; short as in can just be two monosaccharide units, names end in -ose

Furanose

Five-membered ring compouds

Anomers

Isomeric forms of monosaccharides that differ only in their configuration about the hemiacetal or hemiketal carbon atom

N-glycosyl bond

Join the anomeric carbon of a sugar to a nitrogen atom in glycoproteins and nucleotides

Carbohydrate

Polyhydroxy aldehydes or ketones Three classes: monosaccharides, oligosaccharides, and polysaccharides

Monosaccharide

Simple sugar that consists of a single polyhydroxy aldehyde or ketone unit

Pyranose

Six-membered ring compounds

Aldonic acid

Sugar acid obtained by oxidation of the aldehyde functional group of an aldose to form a carboxylic acid

Uronic acid

Sugar acid obtained by oxidation of the terminal carbon's hydroxyl group to form a carboxylic acid

Polysaccharides

Sugar polymers containing more than 20 or so monosaccharide units

Mutarotation

The alpha and beta anomers of D-glucose interconvert in aqueous solution

O-glycosidic bond

The bond which covalently links two monosaccharides to form a dissacharide

Epimers

Two sugars that differ only in the configuration around one carbon atom

maltose

alpha 1-->4 still reducing

salivary alpha-amylase breaks down starch and glycogen by hydrolyzing random alpha (? --> ?) bonds

alpha 1-4

anomeric carbon are

alpha and beta configurations of the same sugar; for example alpha-D-glucopolyranose and beta-D-glucopolyranose

starch is composed of

amylose and amylopectin

lactose is formed by a glycosidic bond between carbon 1 of beta-galactose and carbon 4 of glucose this is written as

beta (1-->4) glycosidic bond

humans do not produce ? making them unable to digest cellulose

beta (1-->4)endoglucosidases

carbohydrate isomers that differ in configuration around only ONE specific carbon atom are defined as ?

epimers

lactose is a disaccharides made up of

galactose + glucose

sucrose is a disaccharide made up

glucose + fructose

maltose is a disaccharide made up of

glucose + glucose

3 important polysaccharides

glycogen (animal sources) starch (plant sources) unbranched cellulose (plant sources)

bonds that link sugars in polysaccharides are called

glycosidic bonds

D-Deoxyribose

has 5 carbons, the two OH's on the same side, a third has two hydrogens

reducing sugar

hydroxyl group on anomeric carbon is not linked and the ring can open to act as a reducing agent

fructose, glucose, mannose and galactose are all ? of each other

isomers

sucrose

not to good pic, alpha 1->2 beta? non reducing

enzymes known as ? are able to interconvert D and L-isomers

racemases

isomers have the same ? but different ?

same chemical formula; different structures

branched amylopectin and glycogen contain alpha(1-->6) bonds which amylase can't hydrolyze resulting in

short branched and unbranched oligosaccharides called dextrins

example of an epimer between glucose and galactose

they are C-4 epimers structures only differ at C-4 -OH group position

galactose and mannose are NOT epimers, True or False why?

true; differ in position of -OH groups at TWO carbons: C-2 and C-4 therefore they are isomers not epimers