Biology: Carbohydrates, Lipids, and Proteins

Vocabulary practice cards based on lecture notes covering the classification, molecular structure, bonds, and biological functions of carbohydrates, lipids, and proteins.

Carbohydrates

Organic molecules containing the elements carbon, hydrogen and oxygen in a ratio of $1:2:1$ with the empirical formula $(CH_2O)_n$.

Monosaccharides

The basic unit of carbohydrates and the simplest sugar molecules, which are sweet-tasting, soluble in water, and act as reducing sugars.

Aldose

A monosaccharide where the carbonyl group is located at the end of the carbon skeleton as an aldehyde group, such as in glucose.

Ketose

A monosaccharide where the carbonyl group is located in the middle of the carbon skeleton as a ketone group, such as in fructose.

Pentose

A monosaccharide consisting of $5$ carbon atoms, including ribose (RNA component) and deoxyribose (DNA component).

Hexose

A monosaccharide consisting of $6$ carbon atoms, with examples including glucose, galactose, and fructose.

$\alpha$-glucose

An isomer of glucose where the hydroxyl group ($-OH$) on carbon atom $1$ projects below the ring.

$\beta$-glucose

An isomer of glucose where the hydroxyl group ($-OH$) on carbon atom $1$ projects above the ring.

Disaccharides

Molecules formed when two monosaccharides are joined together by a glycosidic linkage through a condensation process.

Glycosidic bond

A covalent bond formed between two monosaccharides during a condensation reaction.

Maltose

A disaccharide formed from the condensation of two $\alpha$-glucose molecules.

Sucrose

A disaccharide formed from the condensation of $\alpha$-glucose and $\beta$-fructose.

Lactose

A disaccharide formed from the condensation of $\beta$-galactose and $\alpha$-glucose.

Condensation

A chemical reaction where two molecules are joined together with the removal of a water molecule.

Hydrolysis

A chemical process where a bond is broken down by the addition of a water molecule.

Amylose

A simple, unbranched type of starch composed of $\alpha$-glucose molecules linked by $\alpha$-1,4 glycosidic bonds.

Amylopectin

A complex, branched type of starch where linear chains of $\alpha$-glucose units are held by $\alpha$-1,4 glycosidic bonds and branches occur at $\alpha$-1,6 glycosidic bonds.

Glycogen

A highly branched polysaccharide of $\alpha$-glucose found in muscle and liver cells, serving as a compact energy storage molecule.

Cellulose

A structural polysaccharide and polymer of $\beta$-glucose that acts as the main component of plant cell walls, featuring $\beta$-1,4 glycosidic linkages.

Triglycerides

A type of lipid consisting of three molecules of fatty acid linked to one glycerol molecule by ester bonds.

Saturated fatty acids

Fatty acids that have only single bonds in the hydrocarbon chain and tend to be solid at room temperature.

Unsaturated fatty acids

Fatty acids containing one or more double bonds between carbon atoms, which cause bending and typically result in a liquid state at room temperature.

Phospholipids

Lipids containing two fatty acid molecules and one phosphate group linked to glycerol, possessing a hydrophilic head and hydrophobic tails.

Steroids

Organic compounds with a carbon skeleton consisting of four fused rings and a variable side chain.

Glycerol

An alcohol with three carbon atoms and three hydroxyl groups ($-OH$), with the molecular formula $C_3H_8O_3$.

Amino acids

The monomer building blocks of proteins, consisting of an amino group ($-NH_2$), a carboxyl group ($-COOH$), and a specific side chain (R group).

Zwitterion

A bipolar ionic molecule that amino acids form at cellular pH (approximately pH 7.4) due to having both positive and negative charges.

Polypeptide

A polymer of amino acids joined together by peptide bonds formed through condensation.

Heparin

A complex polysaccharide produced in basophils that acts to prevent or dissolve blood clotting.

RuBP

Ribulose bisphosphate, a $CO_2$ acceptor in photosynthesis that is a derivative of pentose sugars.