Exam 3: Metabolism and Enzymes Flashcards
metabolism
the chemical reactions that occur in living cells through various pathways that utilize enzymes
catabolism
a specific type of metabolism that breaks down molecules to release energy
anabolism
a specific type of metabolism that uses energy to construct molecules for use in the cell
potential energy
the energy in a system due to the position or arrangement of the system
kinetic energy
the energy in a system due to motion
Gibb’s free energy
the amount of available potential energy in a system, or the amount of work that can be extracted from the system
enthalpy
the total energy of a system
entropy
the disorder of a system; systems tend toward increased entropy
spontaneous process
a reaction that will occur without the addition of external energy; the rate of the reaction is not related to its spontaneity; includes exergonic reactions
nonspontaneous process
a reaction that needs additional energy to proceed; includes endergonic reactions
exergonic reaction
a reaction in which energy flows from the system to the environment; exergonic reactions are spontaneous
endergonic reaction
a reaction in which energy flows from the environment to the system; endergonic reactions are nonspontaneous
enzyme
proteins that increase the rate of reactions, usually by lowering the activation energy
activation energy
the amount of energy needed in order to catalyze a chemical reaction
substrate
molecule that binds to the active site of an enzyme and forms a substrate-enzyme complex
product
the molecule that is released from an enzyme after a reaction is catalyzed
active site
the part of an enzyme where a substrate binds; recognizes substrates specific to the enzyme
allosteric site
a site on the enzyme (not the active site) to which molecules can bind
competitive inhibitor
inhibits the function of an enzyme by binding to the active site and preventing the formation of the enzyme-substrate complex
noncompetitive inhibitor
inhibits the function of an enzyme by preventing the enzyme-substrate complex from completing the reaction and producing a product
allosteric activator
a molecule that binds to an allosteric site and increases the affinity of the active site for the substrate
allosteric inhibitor
a molecule that binds to an allosteric site and decreases the affinity of the active site for the substrate
feedback inhibition
inhibition that occurs when a product of the enzymatic reaction binds to and inhibits the same enzyme
cofactors
an organic or inorganic molecule that binds to a protein and facilitates its biological function
