Macromolecules #2 (Biology 31) - Vocabulary Flashcards

Vocabulary flashcards covering key concepts from the Macromolecules notes: carbohydrates, lipids, proteins, and nucleic acids.

Carbon

A tetravalent element whose four covalent bonding positions enable the wide diversity of organic molecules essential to living things.

Carbohydrates

Macromolecules that provide energy, offer structural support, and can act as cell-surface receptors; classified as monosaccharides, disaccharides, and polysaccharides.

Monosaccharide

A simple sugar; the basic unit of carbohydrates.

Disaccharide

Two monosaccharide units linked by a glycosidic bond.

Polysaccharide

Long chains of monosaccharides forming complex carbohydrates for storage or structure.

Lipids

Nonpolar, hydrophobic macromolecules including fats/oils, waxes, phospholipids, and steroids.

Triglyceride

A fat/oil composed of glycerol with three fatty acids; primary form of stored energy.

Fatty acid

Long hydrocarbon chain with a terminal carboxyl group; building block of lipids.

Glycerol

Three-carbon backbone to which fatty acids attach in triglycerides and phospholipids.

Phospholipid

Lipid with a glycerol backbone, two fatty acids, and a phosphate group; major component of cell membranes.

Sterol

Lipid class with four-ring structure; includes cholesterol and steroid hormones.

Cholesterol

Key membrane component in animals and precursor to other steroids (e.g., estrogen, testosterone).

Protein

Macromolecule with diverse cellular functions; built from amino acids; has four structural levels: primary, secondary, tertiary, and quaternary.

Amino acid

Building block of proteins; contains a central carbon, an amino group, a carboxyl group, and a variable side chain.

Peptide bond

Covalent bond linking amino acids via a dehydration reaction.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Alpha-helix or beta-pleated sheet formed by hydrogen bonds.

Tertiary structure

Three-dimensional folding of a polypeptide due to side-chain interactions, giving a unique shape and function.

Disulfide bridge

Covalent bond between sulfur atoms (often in cysteine) stabilizing the protein's structure.

Hydrogen bond

Noncovalent bond important in stabilizing secondary and tertiary protein structures.

Ionic bond

Electrostatic bond between charged side chains contributing to protein structure.

Van der Waals interactions

Weak attractions between nonpolar regions contributing to protein folding.

Quaternary structure

Assembly of multiple polypeptides into a functional protein.

Denaturation

Unfolding of a protein due to heat, pH, or chemicals, resulting in loss of function.

Hydrophobic

Water-repelling; nonpolar; tends to cluster away from water.

Hydrophilic

Water-attracting; polar or charged; interacts with water.

Nucleic acids

Polymers made of nucleotides that direct cellular activities (cell division, protein synthesis); two types: DNA and RNA.

Nucleotide

Monomer of nucleic acids; consists of a phosphate group, a five-carbon sugar, and a nitrogenous base.

DNA

Deoxyribonucleic acid; double-stranded; sugar is deoxyribose; bases A, T, C, G.

RNA

Ribonucleic acid; typically single-stranded; sugar is ribose; bases A, U, C, G.

Ribose

Five-carbon sugar used in RNA.

Deoxyribose

Five-carbon sugar used in DNA; lacks one oxygen atom.

Glycosidic bond

Covalent bond joining sugar units in carbohydrates.

Ester linkage

Bond between glycerol and fatty acids in lipids (as in triglycerides).

Phospholipid bilayer

Two-layered membrane structure formed by phospholipids; glycerol backbone with fatty acid tails and a phosphate-containing head.