Overview Metabolism represents all of the chemical activity in a cell, including reactions that build molecules (anabolism) and those that break ...

The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed. This can be demonstrated within a classic food web ...

The Second Law of Thermodynamics states that entropy, or the amount of disorder in a system, increases each time energy is transferred or transformed. ...

Kinetic energy is the ability of an object in motion to do work or enact change. It can take on many forms. For instance, water flowing down a waterfall ...

The energy stored by a structure and location of matter in space is called potential energy. For instance, raising a kettlebell changes its spatial ...

Free energy—abbreviated as G for the scientist Gibbs who discovered it—is a measurement of useful energy that can be extracted from a reaction ...

Activation energy is the minimum amount of energy necessary for a chemical reaction to move forward. The higher the activation energy, the slower the rate ...

The bonds of adenosine triphosphate (ATP) can be broken through the addition of water, releasing one or two phosphate groups in an exergonic process ...

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications ...

Most chemical reactions in cells require enzymes—biological catalysts that speed up the reaction without being consumed or permanently changed. They ...

Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the ...

Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of ...

Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that speed ...

Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the ...

Enzymes require additional components for proper function. There are two such classes of molecules: cofactors and coenzymes. Cofactors are metallic ions ...