Lipids and Carbohydrates Vocabulary

Vocabulary practice flashcards covering lipid chemistry, lipid classes, carbohydrate structures, sugar isomerism, glycosidic linkages, polysaccharides, and glycoconjugates based on lecture notes.

Fatty Acids

Lipid molecules that serve as fuel, consisting of a hydrocarbon chain with a carboxylic acid group at the end.

Saturated Fatty Acids

Fatty acids containing only single bonds within their hydrocarbon chain.

Unsaturated Fatty Acids

Fatty acids containing one or more double bonds in their hydrocarbon chain.

Triacylglycerols

Storage fatty acids composed of $3$ fatty acids and $1$ glycerol molecule, serving as long-term energy storage in adipose tissue.

Phospholipids

A major class of membrane lipids composed of a platform backbone (glycerol or sphingosine), $1$ or more fatty acids, a phosphate group, and an alcohol group.

Phosphoglycerides

A class of phospholipids containing a glycerol backbone and $2$ fatty acids.

Sphingolipids

A class of phospholipids composed of $1$ fatty acid and a sphingosine backbone, which is a complex alcohol containing an amino group.

Glycolipids

Membrane lipids composed of carbohydrates (a fatty acid, sugar unit, and OH groups) with a sphingosine backbone and no phosphate group.

Cerebrosides

The simplest type of glycolipid, containing a single sugar molecule.

Steroids

Polycyclic hydrocarbon lipids built around a fused steroid nucleus containing $3$ cyclohexane rings and $1$ cyclopentane ring.

Cholesterol

The most common steroid, found exclusively in eukaryotes, containing a hydrophobic chain and polar hydroxyl group; it controls membrane fluidity and acts as a hormone precursor.

Lipid-linked Proteins

Proteins covalently bound to lipids containing a hydrophobic group that localizes the protein to the inner-face of the cell membrane.

GPI-linked Proteins

Proteins anchored by a GPI group that localizes the protein to the extracellular face of the cell membrane.

Monosaccharides

The simplest carbohydrates, consisting of an aldehyde or ketone with $2$ or more alcohol groups, having at least $3$ carbons.

Ketose

A monosaccharide featuring a ketone group, having no stereogenic carbons and no enantiomers.

Aldose

A monosaccharide featuring an aldehyde group with $1$ stereogenic carbon and present enantiomers.

Fischer Projections

Representations used to describe stereochemistry where vertical bonds project behind the plane and horizontal bonds project in front of the plane.

Epimers

Isomers that differ in stereochemistry at only one chiral carbon, such as D-glucose and D-mannose.

Anomers

Isomers that differ in stereochemistry at the new chiral carbon created upon ring closure.

Pyranose

A $6$-membered cyclic sugar ring formed by the reaction of an aldehyde and an alcohol (hemiacetal).

Furanose

A $5$-membered cyclic sugar ring formed by the reaction of a ketone and an alcohol (hemiketal).

Reducing Sugar

A carbohydrate possessing a free aldehyde or ketone group with a free OH on the anomeric carbon, capable of reacting with oxidizing agents.

HbA1C

A glycosylated form of hemoglobin created when reducing sugars react with hemoglobin, used to monitor blood sugar control in diabetics.

O-glycosidic Bond

A glycosidic linkage formed between the anomeric carbon of a monosaccharide and an OH group.

N-glycosidic Bond

A glycosidic linkage formed between the anomeric carbon of a monosaccharide and an amine group.

Maltose

A disaccharide composed of two D-glucose units connected by an $\alpha(1,4)$ O-glycosidic bond, which is broken down by maltase at the brush border.

Lactose

A disaccharide composed of galactose and glucose connected by a $\beta(1,4)$ O-glycosidic bond, which is broken down by lactase.

Sucrose

A non-reducing disaccharide composed of glucose and fructose linked via an $\alpha-1,\beta-2$ bond, cleaved by sucrase.

Glycogen

A glucose storage homopolymer in animals featuring a helical structure held by $\alpha-1,4$ bonds with less common $\alpha-1,6$ branch points.

Starch

Plant energy storage consisting of amylose ($\alpha-1,4$ linkages) and amylopectin ($\alpha-1,4$ and $\alpha-1,6$ linkages), broken down by $\alpha\text{-amylase}$.

Cellulose

A glucose homopolymer linked by $\beta-1,4$ bonds that forms a linear structure for stronger structural interactions.

Glycosaminoglycans

Polysaccharides composed of repeating disaccharides that contain an amino group and a negatively charged group.

Proteoglycans

Molecules mainly composed of carbohydrate (glycosaminoglycans) attached to proteins, serving as key components of the extracellular matrix and lubricants.

Glycoproteins

Proteins modified by carbohydrates where the protein component is the largest, linked via ASN (N-linkage), SER (O-linkage), or THR (O-linkage).

Mucins

Heavily glycosylated proteins consisting mostly of carbohydrates with many O-glycosylation linkages, serving to lubricate and protect mucus membranes.