Energy, Chemical Reactions, and Enzymes

Potential energy

Stored energy (energy of position)

Kinetic energy

Energy of motion

Chemical Energy

Energy stored in a molecule's chemical bonds

Electrical energy

Movement of charged particles

Mechanical energy

Objects in motion due to applied force

Sound energy

Molecule compression caused by a vibrating object

Radiant energy

Energy of electromagnetic waves

Heat

Kinetic energy of random motion

Chemical reactions

Atoms, ions, molecules or compounds interact to form or break chemical bonds

Reactants

Substances that enter into a chemical reaction

Products

Substances that result from the reaction

Catabolic reaction

Initial large molecule broken down into smaller structures

Anabolic reaction

Two or more structures combined to form a larger structure

Exchange reaction

Groups exchanged between two chemical structures

Redox Reactions

Electrons moved from one chemical structure to another

Exergonic reactions

Reactants with more potential energy within their chemical bonds than products: Energy released

Endergonic reactions

Reactants with less potential energy within their chemical bonds than products: Energy supplied

ATP

Energy currency of the cell

Irreversible reaction

Net loss of reactants and a net gain in products

Reversible reaction

Reactants become products and products become reactants at equal rate

Activation energy (Ea)

Energy required to break existing chemical bonds

Law of mass action

Increasing the amount of reactants will increase the reaction rate in the forward direction

Phosphorylation

Addition of phosphate group

Dephosphorylation

Removal of phosphate group