Protein Structure and Function

These flashcards cover essential vocabulary and concepts related to proteins and their structure & function, crucial for understanding biochemistry.

Protein

An unbranched polymer made of amino acids.

Amino acid

An organic compound containing an amino group and a carboxylic acid group.

R-group

The distinguishing part of an amino acid that determines its classification.

Zwitterion

A molecule that contains both negative and positive charges but is electrically neutral.

Isoelectric Point (pI)

The pH at which a molecule has an overall charge of zero.

Electrophoresis

A process used to separate charged particles based on their migration toward charged electrodes.

Dipeptide

A peptide composed of two amino acids.

Disulfide linkage

A covalent bond formed between the sulfur atoms of two cysteine residues.

Primary structure

The specific amino acid sequence of a polypeptide.

Secondary structure

The folding or coiling of the polypeptide backbone into shapes like α-helices and β-sheets.

Tertiary structure

The overall 3-D shape of a polypeptide resulting from interactions between R-groups.

Quaternary structure

The assembly of multiple polypeptide chains into a functioning protein complex.

Fibrous protein

Proteins with elongated structures, often water-insoluble, that serve structural functions.

Globular protein

Proteins that are folded into spherical or globular shapes, typically water-soluble.

Contractile proteins

Proteins that respond to nerve stimuli and change shape to enable movement.

Catalytic proteins

Enzymes responsible for accelerating biochemical reactions.

Buffer proteins

Proteins that help maintain pH balance in biological systems.

Hydrophobic interaction

Forces that drive nonpolar R-groups to the interior of proteins away from water.

Peptide bond

The covalent bond that links amino acids in a protein.

Sulfhydryl group

A functional group characterized by the presence of sulfur and hydrogen (–SH).

Prosthetic group

A non-amino acid component that is covalently bonded to a protein, essential for its function.