bio exam 2 prep: Proteins and Enzymes

Amino Acid

The building block monomer of proteins; contains an amino group, a carboxyl group, a hydrogen, and a unique R group attached to a central carbon

R Group (Side Chain)

The variable part of an amino acid that gives each of the 20 different amino acids its specific chemical properties (e.g., nonpolar, polar, acidic, or basic)

Peptide Bond

The bond created between two amino acids when they link together through dehydration synthesis

Primary Structure

The exact, linear order of amino acids in a protein chain

Secondary Structure

Early folding into spirals (αα-helices) or flat sheets (ββ-pleated sheets) held together by hydrogen bonds

Tertiary Structure

he overall 3D shape formed when the R groups interact with each other and water

Quaternary Structure

The final shape created when two or more distinct protein chains lock together

Denaturation

When extreme heat or severe pH changes ruin a protein’s 3D shape, making it unable to function (like frying an egg)

Enzyme

A protein catalyst that speeds up chemical reactions by lowering the activation energy

Activation Energy

The minimum energy hurdle needed to start a chemical reaction

Substrate

The specific target molecule that an enzyme acts on

Active Site

The specific spot on an enzyme where the substrate fits like a key in a lock

Competitive Inhibitor

A molecule that blocks a reaction by competing directly with the substrate to sit in the enzyme's active site

Noncompetitive Inhibitor

A molecule that attaches to a different spot on the enzyme, changing the active site's shape so the substrate can't work properly

Cofactor

A non-protein helper molecule that must attach to an inactive enzyme to switch it into its active form