Biology: Protein Structure, Enzymes, and Metabolic Pathways

Amino Acid

Organic compounds that serve as the building blocks of proteins, containing an amino group, a carboxylic acid group, and a unique R group.

Carboxylic Acid Group

A functional group characterized by a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (-COOH).

Amino Group

A functional group consisting of a nitrogen atom bonded to two hydrogen atoms (-NH2), commonly found in amino acids.

R Group

The side chain of an amino acid that determines its unique properties and characteristics.

Peptide Bond

A covalent bond formed between two amino acids during protein synthesis, linking the carboxyl group of one amino acid to the amino group of another.

Dehydration Synthesis

A chemical reaction in which two molecules are joined together with the removal of a water molecule, commonly used to form peptide bonds.

Primary Structure

The linear sequence of amino acids in a polypeptide chain, determining the protein's identity and function.

Secondary Structure

The local folded structures that form within a protein due to hydrogen bonding, including alpha helices and beta sheets.

Tertiary Structure

The overall three-dimensional shape of a protein, formed by the interactions between the R groups of amino acids.

Quaternary Structure

The structure formed when two or more polypeptide chains aggregate to form a functional protein.

Enzyme

A biological catalyst that speeds up chemical reactions in living organisms by lowering the activation energy.

Substrate

The reactant molecule upon which an enzyme acts during a biochemical reaction.

Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Activation Energy

The minimum amount of energy required to initiate a chemical reaction.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed or permanently altered by the reaction.

Hydrolysis

A chemical reaction in which water is used to break down a compound, often involving the cleavage of peptide bonds.

Denaturation

The process in which a protein loses its native structure and function due to factors such as heat, pH changes, or chemical exposure.

Competitive Inhibitor

A substance that competes with the substrate for binding to the active site of an enzyme, reducing the enzyme's activity.

Noncompetitive Inhibitor

A substance that binds to an enzyme at a site other than the active site, decreasing the enzyme's activity regardless of substrate concentration.

Allosteric Site

A specific site on an enzyme, separa

te from the active site, where molecules can bind and influence the enzyme's activity.

Cofactor

A non-protein chemical compound that is required for the biological activity of some enzymes, often acting as a helper molecule.

Metabolic Pathway

A series of chemical reactions occurring within a cell that lead to the conversion of a substrate into a product, often regulated by enzymes.