Ch. 6 Flashcards
____ transforms matter into energy
metabolism
usually metal ions found in the active site participating in catalysts
cofactors
nonprotein organic molecules, often used as an electron donor or acceptor in a redox reaction
coenzymes
substance that speeds up the rate of a chemical reaction
catalyst
release energy by breaking down complex molecules into simpler compounds
catabolic pathways
consume energy to build complex molecules from simpler ones
anabolic pathways
biochemical pathways are often regulated by
feedback inhibition
loss of electrons
oxidation
gain of electrons
reduction
first law of thermodynamics
energy cannot be created nor destroyed
energy can only be converted from one form to another
disorder in the universe
entrophy
second law of thermodynamics
disorder is more likely than order
entropy is always increasing
energy able to do work
free energy
energy contained in a molecule’s chemical bonds
enthalpy
when products contain more free energy than reactants
delta G is positive
when reactants contain more free energy than products
delta G is negative
extra energy needed to get a reaction started
activation energy
substances that lower the activation energy of a reaction
catalysts
absorption of energy, products > than free energy
endergonic
release of energy
exergonic
energy currency of cells
ATP
ATP structure
ribose(5-carbon sugar), adenine, three phosphates
ATP stores energy in the
bonds between phosphates
phosphates repelling each other means
a lot of energy is required to keep them together
molecules that catalyza reactions in living cells
biological catalysts
molecule that will undergo a reaction
substrates
region of the enzyme that binds to the substrate
active site
multienzyme complexes advantages
production of the reaction can be directly delivered to the next enzyme
unwanted side reactions eliminated
all reactions controlled as a unit
RNA molecules with enzymatic abilities
ribozymes
conditions that affect the enzymes’ 3-dimensional shape
optimum temperature & optimum pH
molecules that bind to enzyme to decrease enzyme activity
inhibitors
complete with a substrate for binding to the same active site
competitive inhibitors
bind to sites other than the active site causing shape change and makes enzyme unable to bind to substrate
noncompetitive inhibitors
exist in either an active or inactive state
allosteric enzyme
bind to allosteric site to inactive the enzyme
allosteric inhibitors
bind to the allosteric site to activate the enzyme
allosteric activators
