Energy, ATP, and Enzymes

Energy

The ability to do work, moving matter against opposing forces.

Kinetic Energy

The energy of motion.

Potential Energy

Stored energy, the capacity to do work.

Thermodynamics

The study of energy transformation.

First Law of Thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

Second Law of Thermodynamics

Every energy transfer increases the entropy of the universe.

Free Energy

The portion of a system's energy that can perform work.

Exergonic Reaction

A process with a net release of free energy.

Endergonic Reaction

A process which absorbs free energy from the surroundings.

Energy Coupling

The use of an exergonic process to drive an endergonic process.

ATP

Adenosine triphosphate, a high-energy molecule used in cellular work.

Enzyme

A protein catalyst that speeds up chemical reactions without being consumed.

Substrate

Reactants in an enzyme-catalyzed reaction.

Cofactors

Non-protein enzyme helpers, which can be inorganic or organic.

Induced Fit

The change in shape of an enzyme to better fit the substrate.

Active Site

The region of an enzyme that binds to the substrate.

Saturation

When an enzyme's active site is filled to its maximum capacity.

Denatured Protein

When a protein loses its structure and function due to environmental factors.

Allosteric Site

A receptor site on an enzyme remote from the active site that can regulate function.

Feedback Inhibition

When the product of a pathway inhibits an earlier step of the pathway to prevent excess product.