Unit 3 (Enzymes only)

catabolic

A process in which large molecules are broken down

enzymes

protein substances that speed up chemical reactions.

catalysts

Chemical agents that selectively speed up chemical reactions

exergonic reactions

chemical reactions that involve a net release of free energy

endergonic reactions

reactions that absorb energy; the products have more energy than the reactants

activation energy

the energy that an atomic system must acquire before the reaction can occur

lock and key model

The model of the enzyme that shows the substrate fitting perfectly into the active site

substrates

the reactants of enzyme-catalyzed reactions

active site

the site on an enzyme that attaches to a substrate

induced fit

The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.

coenzymes

An organic molecule that is a necessary participant in some enzymatic reactions; the "buddy" system

allosteric sites

a region of the enzyme other than the active site to which a substrate can bind

activator

binds to the enzyme and induces the enzyme's active form, to speed up the reaction

competitive inhibition

A molecule that enters the active site in place of the substrate, which can slow or stop the reaction

noncompetitive inhibition

the act of binding to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

anabolic

A process in which large molecules are built from small molecules

ATP Synthase

Large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

Metabolism

All of the chemical reactions that occur within an organism, pathways that are led by enzymes

Factors that affect enzymes

pH, temperature, salt content

Denature

a change in shape that stops the protein (enzyme) from functioning.

Optimal Range

the range of environmental factors to which an enzyme is best adapted

-ase

the suffix of MOST enzymes