Looks like no one added any tags here yet for you.
what is metabolism
al the chemical reactions in an organism
enzymes help regulate the ____ of metabolic pathways
rate/speed
two types of metabolic pathways
catabolic and anabolic
catabolic pathways characteristics
breakdown pathways, complex to simpler, spontaneous, exergonic, energy release, downhill reactions
anabolic pathways characteristics
synthesis pathways, simple to complex, non-spontaneous, endergonic, consume energy, uphill reactions
an organisms metabolism ___ matter and energy
transforms
1st law of thermodynamics
principle of conservation of energy: energy can’t be created or destroyed, total energy of the universe is constant
2nd law of thermodynamics
entropy (disorder): every energy transformation or transfer results in increasing entropy, as energy is transferred, more energy is wasted (unavailable for work)
what is free energy
the portion of a systems energy available to perform work when the systems temperature and pressures are uniform
exergonic reactions
energy outward, spontaneous reaction in which there is a net release of free energy
endergonic reactions
energy inward, non-spontaneous reactions in which free energy is absorbed from the surroundings
reactions in an isolated system will naturally move toward ___
equilibrium
equilibrium and cells
cells are never at equilibrium because of the constant flow of materials in and out of the cell, a cell at equilibrium is a dead cell
energy source used to drive most types of cellular work
ATP
hydrolysis of ATP to ADP
the bond between the final two phosphate groups is broken by hydrolysis, which produces ADP, exergonic reaction
catalyst
a substance that can change the rate of a reaction without being altered in the process
enzyme
a protein catalyst that changes the rate of a reaction without being consumed
bonds are broken and formed in ___
chemical reactions
form bonds to break, ___
reactants must absorb energy from their surroundings
activation energy
energy needed initially to reach transition state, in which bonds can be broken and from which the reaction can proceed
how do enzymes speed up reactions
enzymes lower the activation energy, allowing the reaction to start sooner and proceed quicker
how does temperature effect enzyme activity
each enzyme has an optimal temperature, too much heat breaks enzyme bonds and denatures it
how does pH effect enzyme activity
enzymes have optimal pH between 6 and 8, the enzyme will denature if it goes above or beyond that
cofactors
any non-protein molecule that is required for the proper functioning of an enzyme
coenzyme
a cofactor that is an organic molecule
how is enzyme activity regulated
the cell switches on and off the genes that encode specific enzymes, or the cell regulates their activity once they are made
substrate
the reactant that an enzyme acts on
active site
region on an enzyme where the substrate binds
competitive inhibitors
molecules that resemble the normal substrate and compete to bind to the active site
noncompetitive inhibitors
inhibitors that bind to the other part of the enzyme causing it to change shape so the substrate can’t bind to the active site
feedback inhibition
way in which metabolic pathways are regulated
how does feedback inhibition work
end product shuts down pathways by binding to allosteric site, ATP can act as a feedback inhibitor