Bio ch 8 vocab

Activation energy

the initial energy needed to break the bonds of reactants

Active site

the region on the enzyme that binds the substrate

Allosteric regulation

when a regulatory molecule binds to a protein at one site and affects the protein's function at another site

Anabolic pathways

consume energy to build complex molecules from simpler ones

Bioenergetics

the study of how energy flows through living organisms

Catabolic pathways

release energy by breaking down complex molecules into simpler compounds

Catalysis

the process by which a catalyst selectively speeds up a reaction without itself being consumed

Catalyst

chemical agent that speeds up a reaction without being consumed

Chemical energy

the potential energy available for release in a chemical reaction

Coenzymes

organic cofactors

Cofactors

nonprotein helpers that bind to the enzyme permanently or reversibly with substrate

Competitive inhibitors

closely resemble the substrate and can bind to the enzyme's active site

Cooperativity

substrate binding to one active site triggers a shape change in the enzyme that stabilizes the active form for all other sites

Endergonic reaction

absorbs free energy from the surroundings

Energy coupling

the use of an exergonic process to drive an endergonic one

Entropy

the measure of molecular disorder or randomness

Enzyme-substrate complex

when the enzyme and its substrate are bound, before the reaction commences

Exergonic reaction

proceeds with a net release of free energy to the surroundings ("energy outward")

Feedback inhibition

the end product of a metabolic pathway shuts down the pathway

First law of thermodynamics

energy can be transferred and transformed but it cannot be created or destroyed

Free energy

the portion of a system's energy that can do work when temperature and pressure are uniform throughout the system (as in a living cell)

Induced fit

results from interactions between chemical groups on the substrate and the active site

Metabolic pathway

a specific molecule is altered in a series of steps to produce a product. Each step is catalyzed by a specific enzyme

Metabolism

the totality of an organism's chemical reactions

Noncompetitive inhibition

bind to another part of the enzyme, away from the active site

Phosphorylated intermediate

the recipient molecule of phosphorylation, typically less stable with more free energy

Second law of thermodynamics

every energy transfer or transformation increases the entropy of the universe

Spontaneous processes

occur without energy input; they can happen quickly or slowly

Substrate

the reactant that an enzyme acts on

Thermodynamics

the study of energy transformations in a collection of matter