Biochemistry: Carbohydrates, Glycoproteins, and Glycolipids Vocabulary

Vocabulary flashcards covering carbohydrate terminology, sugar derivatives, disaccharide linkages, polysaccharides, glycoprotein types, blood group glycolipids, and viral entry mechanisms from biochemistry lecture notes.

Mutarotation

The dynamic interconversion between $\alpha$ and $\beta$ anomeric forms of a sugar via the open-chain (linear) intermediate.

Haworth Perspectives

Flat-ring representations used to draw closed-ring carbohydrate structures.

Beta-Glucose Chair Conformation

The thermodynamically favored carbohydrate conformation representing approximately $66\%$ of the equilibrium population because all $\text{OH}$ groups occupy equatorial positions.

Alpha-Glucose Chair Conformation

The form of glucose that constitutes approximately $34\%$ of the equilibrium population at dynamic equilibrium.

Glucopyranose

The six-membered pyranose ring structure formed by cyclic glucose.

Fructofuranose

The five-membered furanose ring structure formed by cyclic fructose.

GLC

The standard three-letter biochemical abbreviation for glucose.

FRU

The standard three-letter biochemical abbreviation for fructose.

GlcNAc

The biochemical abbreviation for N-acetylglucosamine.

GalNAc

The biochemical abbreviation for N-acetylgalactosamine.

Glycosidic Bond

An acetal or ketal linkage formed when an anomeric carbon reacts with an alcohol group, releasing water.

Maltose

A disaccharide consisting of two glucose units joined by an $\alpha\text{-1,4}$ glycosidic bond.

Lactose

A disaccharide consisting of galactose and glucose units.

Sucrose

A disaccharide of glucose and fructose linked via both anomeric carbons, leaving no free aldehyde and preventing mutarotation.

Cellulose

An unbranched plant structural polysaccharide composed of all-glucose residues joined by $\beta\text{-1,4}$ glycosidic linkages.

Beta-glucosidase

An enzyme produced by gut bacteria in ruminants that cleaves $\beta\text{-1,4}$ glycosidic linkages in cellulose.

Amylose

The unbranched, linear component of starch composed of $50$ to $5{,}000$ glucose units linked by $\alpha\text{-1,4}$ glycosidic bonds.

Amylopectin

A branched form of starch containing up to $1\text{ million}$ glucose units with $\alpha\text{-1,6}$ branch points occurring every $24$ to $30$ glucose residues.

Glycogen

An animal energy storage polysaccharide containing up to $50{,}000$ glucose residues with $\alpha\text{-1,6}$ branch points every $8$ to $12$ residues.

Fehling's Test

A historical chemical assay where a reducing sugar reduces $\text{Cu}^{2+}$ to $\text{Cu}^+$ under basic conditions, producing a red copper oxide precipitate.

Glucose Oxidase

An enzyme immobilized on diagnostic test strips that acts on glucose to generate hydrogen peroxide proportional to glucose concentration.

O-Linked Glycoprotein

A glycoprotein formed by attaching a carbohydrate to the $\text{OH}$ side chain of a serine or threonine residue.

N-Linked Glycoprotein

A glycoprotein formed by attaching a carbohydrate to the nitrogen of an asparagine residue, sharing a core structure of $2$ GlcNAc and $3$ mannose residues.

Proteoglycans

High carbohydrate-to-protein complexes present in cartilage that retain water and function as physical shock absorbers in joints.

Type O Blood Antigen Base

The core glycolipid structure present on red blood cells composed of galactose, GlcNAc, galactose, and fucose.

Type A Blood Antigen

A glycolipid antigen formed by adding GalNAc to the core blood group carbohydrate base.

Type B Blood Antigen

A glycolipid antigen formed by adding an additional galactose residue to the core blood group carbohydrate base.

Hemagglutinin (H)

An influenza surface protein that binds host cell carbohydrates to enable viral entry via endocytosis.

Neuraminidase (N)

An influenza surface enzyme that cleaves carbohydrate linkages to allow newly assembled viral particles to bud from the host cell.

Oseltamivir (Tamiflu)

An antiviral drug that acts as a neuraminidase inhibitor to prevent influenza viral budding.

Zanamivir (Relenza)

An antiviral medication that inhibits neuraminidase to prevent viral release from host cells.