Bio 1201 Chapter 8 Vocab

An introduction to Metabolism

Metabolism

The totality of an organism’s chemical reactions

Metabolic pathway

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

Catabolic pathways

–release energy by breaking down complex molecules into simpler compounds

Anabolic pathways

consume energy to build complex molecules from simpler ones

Bioenergetics

the study of how energy flows through living organisms

Chemical energy

the potential energy available for release in a chemical reaction

Thermodynamics

the study of energy transformations in a collection of matter

First law of thermodynamics

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

Second law of thermodynamics

every energy transfer or transformation increases the entropy of the universe

Entropy

The measure of molecular disorder or randomness

Spontaneous Processes

occur without energy input, they can happen quickly or slowly

Free energy

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

Exergonic reaction

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

Endergonic reaction

absorbs free energy from the surroundings

Energy coupling

•the use of an exergonic process to drive an endergonic one

Phosphorylated intermediate

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

Catalyst

chemical agent that speeds up a reaction without being consumed

Activation energy

•the initial energy needed to break the bonds of reactants

Substrate

•the reactant that an enzyme acts on

Enzyme-substrate complex

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

Active site

•the region on the enzyme that binds the substrate

Induced fit

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

Cofactors

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

Coenzymes

organic cofactors

Competitive inhibitors

closely resemble the substrate and can bind to the enzymes active site

Noncompetitive inhibition

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

Allosteric regulation

•when a regulatory molecule binds to a protein at one site and affects the proteins function at another site.

Cooperativity

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

Feedback inhibition

the end product of a metabolic pathway shuts down the pathway