Activation Energy

The initial investment of energy for starting a reaction, the energy required to contort the reactant molecules so the bonds can change. Same as free energy of activation.

Active Site

A pocket or groove on an enzyme and the region the substrate binds to. The active site changes its shape slightly as the substrate enters the active site to create an induced fit.

Allosteric Regulation

Any case in which a protein's function at one site is affected by the binding of a regulatory molecule to a separate site, may inhibit or stimulate enzyme activity.

Anabolic Pathway

Pathway that consumes energy to build complex molecules from simpler ones.

ATP

A nucleic acid consisting of ribose, nitrogenous base adenine, and chain of three phosphate groups. Hydrolysis of the phosphate bonds releases energy.

Bioenergetics

The flow of energy through an animal, taking into account the energy stored in the food it consumes, the energy used for basic functions, activity, growth, reproduction, and regulation, and the energy lost to the environment as heat or in waste.

Catabolic Pathway

Pathway that releases energy by breaking down complex molecules into simpler ones.

Catalyst

A chemical agent that speeds up a reaction without being consumed by the reaction.

Chemical Energy

Potential energy available for release in a chemical reaction.

Coenzyme

Organic Cofactor (i.e. vitamins)

Cofactor

Nonprotein helpers bound permanently to the enzyme or loosely and reversibly along with the substrate that many enzymes require for catalytic activity.

Competitive Inhibitor

Mimics of the substrate that reduce productivity of enzymes by blocking substrates from entering active sites. Can be overcome by increasing the concentration of the substrate.

Cooperativity

The mechanism that amplifies the response of enzymes to substrates; one substrate molecule primes an enzyme to accept additional substrate molecules more readily.

Endergonic Reaction

A reaction that absorbs free energy from its surroundings. (Change in G is positive, not spontaneous)

Energy

Capacity to cause change.

Energy Coupling

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

Entropy

Measure of disorder or randomness; the universe's entropy increases with each energy transfer or transformation.

Enzyme

A catalytic protein.

Enzyme-Substrate Complex

A complex formed when an enzyme binds to its substrate(s). When they're joined, the catalytic action of the enzyme converts the substrate(s) to the product(s).

Exergonic Reaction

A reaction that proceeds with a net release of free energy. (Change in G is negative, is spontaneous)

Feedback Inhibition

A metabolic pathway is switched off by the inhibitory bindings of its end product to an enzyme that acts early in the pathway.

First Law of Thermodynamics

The energy of the universe is constant, energy can be transferred and transferred but not created or destroyed. (Principle of conservation of energy)

Free Energy

Measures the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system.

Free Energy of Activation

The initial investment of energy for starting a reaction, the energy required to contort the reactant molecules so the bonds can change. Same as activation energy.

Heat

Kinetic energy associated with the random movement of atoms or molecules. Same as thermal energy

Induced Fit

Brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction.

Kinetic Energy

Energy associated with the relative motion of objects.

Metabolic Pathway

A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into similar compounds.

Metabolism

The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways.

Noncompetitive Inhibitor

Inhibitors that impede enzyme activity by binding to another part of the enzyme and causing the enzyme to change its shape.

Phosphorylated

Describes the recipient of the phosphate group from ATP.

Potential Energy

Energy that matter posses because of its location or structure

Second Law of Thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

Substrate

The reactant an enzyme acts on.

Thermal Energy

Kinetic energy associated with the random movement of atoms or molecules. Same as heat.

Thermodynamics

The study of energy transformations that occur in a collection of matter