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metabolism
totality of an organism’s chemical reaction
catabolic pathways
breaking down complex molecules into simpler compounds; releases energy
anabolic pathways
building complex molecules from simpler ones; consume/require energy
free energy (G) measures
portion of a system’s energy that can perform work
exergonic reactions ____ free energy
release; product’s G < reactant’s G; - delta G == free energy RELEASED
delta G formula
delta G = gFinal - gInitial
endergonic reactions _____ free energy
absorb; product’s G > reactant’s G; + delta G == free energy REQUIRED
energy coupling
exogonic process to drive an endergonic one
ATP
hydrolysis breaks apart phosphate groups’ bonds; energy released (exergonic) and used for endergonic rxns in the cell
ADP
when ATP is hydrolyzed
activation energy
initial amount of energy the reactants need to absorb to become products
enzymes
proteins that act as biological catalysts; speeds up rxns w/o being used up
how do enzymes speed up metabolic rxns
by lowering the activation energy; do NOT affect delta G of the reaction
substrate
reactants
active site
region on enzyme where substrate binds to
induced fit
binding of substrate to active site
enzyme name
ends in -ase; usually refer to the substrate they bind to / type of reaction they catalyze; ex. lactase catalyzes the hydrolysis of lactose into glucose and galctose
what can denature an enzyme
pH and temp
enzymes’ structure
a sequence of amino acids; folds into specific shape; shape allows for binding to reactants
cofactors
non protein enzyme helps (ex. minerals)
coenzymes
organic cofactors (ex. vitamins)
competitive inhibitor
binds to active site; competes with substrate
noncompetitive inhibitor
binds to another part of the enzyme; enzyme changes shape; active site is nonfunctional
active / inactive conformations
enzymes that can be turned on or off
allosteric regulation
where a protein’s function at one site is affected by binding of a regulatory molecule at another site; can either activate or inhibit
