Chapter 4 Flashcards
energy of motion
kinetic energy
stored energy
potential energy
the study of energy flow during chemical and physical reactions
thermodynamics
energy can be transformed from one form to another or transferred from one place to another, but it cannot be created or destroys. in any process that involves an energy change the total amount of energy in a system and its surroundings remains constant
first law of thermodynamics
the total disorder of a system and its surroundings always increases
second law of thermodynamics
disorder
entropy
chemical or physical reaction that occur without outside help
spontaneous reaction
the potential energy in a system
enthalpy
a reaction in which the products have less potential energy than the reactants; reaction that releases energy
exothermic
a reaction in which the products have more potential ennergy than the reactants
endothermic
the energy in a system that is available to do work
free energy
reaction that has a negative delta G because it releases free energy
exergonic reaction
reaction that can proceed only if free energy is supplied
endergonic reaction
a metabolic pathway in which energy is released by the breakdown of complex molecules to simpler compounds. an individual reaction is a catabolic reaction
catabolic pathway
cellular reaction that breaks down complex molecules such as sugar to make their energy available for cellular work
catabolic reaction
a metabolic pathway in which energy is used to build complicated molecules form simpler ones; biosynthetic pathway; an individual reaction is an anabolic reaction; biosynthetic reaction
anabolic pathway
metabolic reaction that requires energy to assemble simple substance into more complex molecules
anabolic reaction
the process in living cells by which the hydrolysis of ATP is coupled to an endergonic reaction so that energy is not wasted as heat
energy coupling
the addition of a phosphate group to a molecule
phosphorylation
the continual hydrolysis and resynthesis of ATP in living cells
ATP/ADP cycle
the initial input of energy required to start a reaction
activation energy
protein that accelerates the rate of a cellular reaction
enzymes
the process of accelerating a chemical reaction with a catalyst
catalysis
substance with the ability to accelerate a spontaneous reaction without being changed by the reaction
catalyst
the particular reacting molecule or molecular group that an enzyme catalyzes
substrate
the ability of an enzyme to catalyze the reaction of only a single type of molecule or group of closely related molecules
enzyme specificity
the region of an enzyme to which substrate bind and where catalysis occurs
active site
an inorganic or organic nonprotein group that is necessary for catalysis to take place
cofactor
organic cofactors that include complex chemical groups of various kinds
coenzymes
inhibition of an enzyme reaction by an inhibitor molecule that resembles the normal substrate closely enough so that it fits into the active site of the enzyme
competitive inhibition
inhibition of an enzyme reaction by an inhibitor molecule that binds to the enzyme at a site other than the active site and, therefore, does not compete directly with the substrate for binding to the activesite
noncompetitive inhibition
specialized control mechanism for enzymes with an allosteric site, a regulatory site outside the active site, that may either slow or accelerate activity depending on the enzyme
allosteric regulation
a regulatory site outside the active site
allosteric site
molecule that converts an enzyme with an allosteric site, a regulatory site outside the active site, from the inactive form to the active form
allosteric activator
molecule that converts an enzyme with an allosteric site, a regulatory site outside the active site, from the active form to the inactive form
allosteric inhibitor
in enzyme reactions, regulation in which the product of a reaction acts as a regulator of the reaction
feedback inhibition/end-product inhibition
the RNA-based catalyst that is part of the biochemical machinery of all cells
ribozymes
the biochemical reactions that allow a cell or organism to extract energy from its surroundings and use that energy to maintain itself grow and reproduce
metabolism
