Protein Structure and Function – Vocabulary Flashcards (Video Notes)

Vocabulary flashcards covering key concepts from the Protein Structure and Function notes.

Amino acids

Building blocks of proteins; contain an α-carbon, amino group, carboxyl group, hydrogen, and a variable side chain (R).

Monomer

A single structural unit of a polymer.

Polymer

A large molecule made of repeating monomer units.

Polymerization

Bonding together of monomers to form polymers.

Condensation (dehydration) reaction

Joins monomers with loss of a water molecule.

Hydrolysis

Reverse of condensation; breaks polymers by adding water.

Peptide bond

Bond between the carboxyl group of one amino acid and the amino group of another; C–N linkage.

Polypeptide

Chain of amino acids linked by peptide bonds.

N-terminus

End of a polypeptide with a free amino group.

C-terminus

End of a polypeptide with a free carboxyl group.

Backbone

The repeating N–Cα–C chain to which side chains attach; forms the peptide chain.

Side chain (R-group)

The variable group that determines an amino acid's properties; can be acidic, basic, polar, or nonpolar.

Amino group

NH2 group attached to the α-carbon; ionizes in solution.

Carboxyl group

COOH group attached to the α-carbon; ionizes in solution.

Primary structure

The unique sequence of amino acids in a protein; basis for higher levels.

Secondary structure

Forms via hydrogen bonds between carbonyl O and amide N; includes α-helix and β-pleated sheets.

Tertiary structure

3D folding driven by interactions among R-groups: hydrogen bonds, hydrophobic interactions, van der Waals forces, disulfide bonds, and ionic bonds.

Quaternary structure

Higher-level structure formed when two or more polypeptide subunits assemble into a functional protein.

Hydrogen bond

Attraction between a slightly positive H and a slightly negative electronegative atom; stabilizes structures.

Ionic bond

Electrostatic attraction between fully charged groups.

Disulfide bond

Covalent bond between sulfhydryl groups of cysteine residues; stabilizes structure.

Hydrophobic interactions

Driven by avoidance of water; nonpolar side chains cluster together.

Van der Waals interactions

Weak attractive forces between nearby atoms; contribute to tight packing.

Polar side chains

Side chains with partial charges capable of hydrogen bonding.

Nonpolar side chains

Side chains lacking charged or electronegative atoms; tend to be hydrophobic.

Charged side chains

Side chains with full positive or negative charges; form ionic/hydrogen bonds.

Denaturation

Unfolding of a protein; loss of normal structure and function; folding can be disrupted by environmental changes.

Molecular chaperones

Proteins that assist other proteins in folding correctly.

Prions

Altered, infectious misfolded proteins that can cause disease.

Enzymatic proteins

Proteins that catalyze chemical reactions (e.g., digestive enzymes).