22 terms

Cellular Energy & Related Processes Ch 8

contains ribose sugar, nitrogenous base adenosine, and three phosphate groups; energy carrying compound of all cells
catabolic pathways
Release energy by breaking down complex molecules into simpler compounds
anabolic pathways
Consume energy to build complex molecules from simpler ones
the study of energy transformations that occur in a collection of matter
second law of thermodynamics
States that with each successive energy transfer or transformation in a system, less energy is available to do work.
first law of thermodynamics
the principle of the conservation of energy. Energy can't be created or destroyed only transeferred and transformed
free energy
energy that is available to do work
endergonic reaction
A non-spontaneous chemical reaction in which free energy is absorbed from the surroundings.
exergonic reaction
A spontaneous chemical reaction in which there is a net release of free energy.
Referring to a molecule that has been the recipient of a phosphate group.
activation energy
the minimum amount of energy required to start a chemical reaction
reactant of an enzyme-catalyzed reaction
enzyme-substrate complex
A temporary complex formed when an enzyme binds to its substrate molecule(s).
active site
the site on an enzyme that attaches to a substrate
protein that acts as a biological catalyst
induced fit
The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.
Any nonprotein molecule or ion that is required for the proper functioning of an enzyme can be permanently bound to the active site or may bind loosely with the substrate during catalysis.
competitive inhibitors
A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics
noncompetitive inhibitors
A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.
allosteric regulation
The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.
mechanism that amplifies the response of an enzyme; one substrate primes the enzyme to accept additional substrate molecules
feedback inhibition
A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.