Chapter 11. Carbohydrates Flashcards
Molecules that have identical molecular formulas but differ in how the atoms are ordered. For instance, glyceraldehyde and dihydroxyacetone.
Constitutional isomer
The study of the glycome, all of the carbohydrates and carbohydrate-associated molecules that cells produce. Like the proteome, the glycome is not static and can change, depending on cellular and environmental conditions.
Glycomics
a monosaccharide whose C-1 carbon contains an aldehyde group.
Aldose
A pair of molecules, each with more than one asymmetric center, that have opposite configurations at one such center but are not mirror images of each other; in the aldotetrose series, Derythrose and D-threose are diastereoisomers.
Diastereoisomer
Reactions between an amino group in a protein not participating in a peptide bond and the aldehyde form of a carbohydrate. Such reactions frequently compromise protein function.
Advanced glycosylation product
isomers of cyclic hemiacetals or hemiketals, with different configurations only at the carbonyl carbon; that carbon is known as the anomeric carbon.
Anomer
an unbranched homopolysaccharide in plants, composed of glucose residues in α-1,4 linkage; the major structural polysaccharide in plants.
Cellulose
Consists of two sugars joined by an O-glycosidic bond.
disaccharide
The study of the synthesis and structure of carbohydrates and how carbohydrates are attached to and recognized by other molecules such as proteins.
Glycobiology
single aldehydes or ketones that have two or more hydroxyl groups; the simplest carbohydrates.
Monosaccharide
pairs of molecules with one or more chiral centers that are mirror images of each other.
Enantiomer
a monosaccharide that has a ketone group as its most oxidized carbon.
Ketose
a six-membered heterocyclic ring formed when a monosaccharide cyclizes to form a hemiacetal or a hemiketal; the six-membered, oxygen-containing ring is similar to that of pyran.
Pyranose
a five-membered heterocyclic ring formed when a monosaccharide cyclizes to form a hemiacetal or a hemiketal; the five-membered oxygen-containing ring is similar to that of furan.
Furanose
pairs of molecules with more than one asymmetric center that differ in configuration at only one such center; glucose and galactose are epimers, differing only in the configuration at C-4.
Epimer
A readily mobilized storage form of glucose in which the glucose monomers are linked by α-1,4-glycosidic bonds and with branches (α-1,6-glycosidic bonds) at about every tenth residue.
Glycogen
Forms of a specific protein that differ only in patterns of glycosylation.
Glycoform
A protein that binds specific carbohydrate structures on neighboring cell surfaces.
Glycan-binding protein
an extensive system of cytoplasmic membranes that comprises about half the total cell membrane. The region of the ER that binds ribosomes is called the rough ER while the region that is devoid of ribosomes is called the smooth ER.
Endoplasmic reticulum
proteins that have a specific carbohydrate moiety attached.
Glycoprotein
a lipid containing approximately 20 isoprene units that serves as a carrier of oligosaccharides destined to be attached to a protein, through a membrane.
Dolichol phosphate
a compound formed by the reaction of an aldehyde functional group and a hydroxyl group; for example, the C-1 group of the open-chain form of glucose reacts with the C-5 hydroxyl group to form an intermolecular hemiacetal.
Hemiacetal
carbohydrate composed of 2 to 10 or 12 monosaccharide units.
Oligosaccharide
sugars that convert to a form with a free aldehyde group that is readily oxidized, thus reducing another compound.
Reducing sugar
