Biological Molecules

Organic

molecules containing carbon and hydrogen and typically associated with living organisms

Condensation (dehydration) reaction

a reaction that joins monomers by removing a water molecule

Unsaturated fatty acid

a fatty acid with one or more double bonds in its hydrocarbon chain

Tertiary structure

the overall 3D shape of a polypeptide formed by interactions between R-groups

Hydrocarbon

a molecule consisting only of carbon and hydrogen atoms

Hydrolysis

a reaction that breaks bonds between monomers by adding water

Phospholipid

a lipid with a hydrophilic head and hydrophobic tails forming cell membranes

Quaternary structure

the association of multiple polypeptide chains into a functional protein

Isomers

molecules with the same molecular formula but different structures

Monomer

a small molecule that can be linked with others to form a polymer

Steroids

lipids with a carbon skeleton of four fused rings

Denaturation

the loss of a protein’s shape due to heat

Enantiomers

isomers that are mirror images of each other

Polymer

a long molecule made of repeating monomers

Cholesterol

a steroid important for membrane fluidity and as a precursor for hormones

Chaperonin

a protein complex that helps other proteins fold correctly

Functional groups

specific groups of atoms that give molecules characteristic properties

Monosaccharide

the simplest carbohydrate

Protein

a polymer of amino acids folded into a specific 3D structure

Deoxyribonucleic acid (DNA)

the hereditary molecule that stores genetic information

Hydroxyl group

a functional group consisting of –OH

Di or polysaccharide

two or more monosaccharides linked together

Polypeptide

a chain of amino acids linked by peptide bonds

Ribonucleic acid (RNA)

a nucleic acid involved in protein synthesis and gene expression

Carboxyl group

a functional group consisting of –COOH

Glycosidic linkage

the covalent bond that links monosaccharides in carbohydrates

Amino acid

the monomer of proteins containing an amino group

Nucleotide

the monomer of nucleic acids composed of a sugar

Amino group

a functional group consisting of –NH₂

Lipids

hydrophobic biological molecules including fats

Peptide bonds

covalent bonds linking amino acids

Purines

nitrogenous bases with two rings (adenine and guanine)

Phosphate group

a functional group consisting of PO₄³⁻

Fatty acids

long hydrocarbon chains with a carboxyl group at one end

Protein folding

the process by which a polypeptide forms its functional shape

Pyrimidines

nitrogenous bases with one ring (cytosine and thymine)

Methyl group

a functional group consisting of –CH₃

Glycerol

a three-carbon molecule forming the backbone of fats and phospholipids

Conformation

the specific 3D shape of a molecule

Double helix

the two-stranded spiral structure of DNA

Macromolecules

large biological molecules such as proteins

Saturated fatty acid

a fatty acid with no double bonds in its hydrocarbon chain

Primary structure

the linear sequence of amino acids in a protein

Antiparallel

describing DNA strands running in opposite 5'→3' directions

CHNOPS

the six most common elements in biological molecules

Secondary structure

localized folding patterns of a polypeptide such as α-helices and β-sheets

Nitrogenous bases (ACGTU)

the bases found in nucleic acids