bio 3B Flashcards
factors affecting enzymes
how does high temperature affect enzymes
chemical reactions in the body speed up when the internal body temperature increases (molecules have a greater kinetic energy and are more likely to collide against each other HOWEVER enzymes can be denatured at temperatures too high, disrupting the molecule’s structure as it undergoes conformational change in the active site (substrate can no longer fit) (irreversible)
how does low temperature affect enzymes
when it gets too cold, the enzyme activity decreases as they have a lower amount of kinetic energy and they are less likely to collide (reversible)
how does pH affect enzymes
the pH of enzymes ranges depending on where they are located and they have an optimal pH range. when outside of the optimal range, enzyme activity decreases.
how does substrate concentration affect the rate of reaction
if the enzyme concentration remains unchanged while the substrate conc. increases, the reaction rate will increase (more reactants are able to undergo reaction) HOWEVER the saturation point can be reached if the enzyme is saturated with substrates (ROR remains constant at sat. point).
what is a saturation point
the point at which a substance (such as an enzyme) cannot receive more of another substance (such as a substrate)
what happens before the saturation point is reached
before it plateaus, the factor affecting the rate of reaction is a limiting reagent in the reaction
what happens after the saturation point is reached
after it plateaus, the factor affecting the rate of reaction is no longer the limiting reagent
how does enzyme concentration affect the rate of reaction
if the enzyme conc. is high while the substrate conc. is constant, the rate of reaction increases due to the high number of active sites available. HOWEVER when the enzymes are in excess while the substrate conc. remains constant, the ROR will plateau regardless of the enzyme conc.
what are inhibitors
molecules that bind to enzymes and prevent them from performing its function (they can either no longer function or the function is greatly reduced)
what is competitive inhibition
enzymes are impeded by active sites being blocked as the competitive inhibitors have a shape that is complementary to the active site (the substrate and comp. inhibitor compete for the active site)
what is non-competitive inhibition
the non-competitive inhibitors interfere with enzymes by binding to a site other than the active site (allosteric site) and induces conformational change of the active site
what is reversible inhibition
the inhibitor binds weakly to the enzyme site (bonds can be broken and overcome when the amount of substrate increases) to slow the rate of a given enzyme-catalyst reaction
what is irreversible inhibition
the inhibitor forms strong bonds with the enzyme (cannot be broken) meaning the enzyme is unable to perform indefinitely, regardless of the amount of substrate present
why is the inhibition of biochemical pathways needed
to regulate how much of a certain product is created (depends on body’s needs)
what are coenzymes
they assist enzymes in catalysing reactions and are a subset of cofactors (organic/inorganic molecule). the enzyme remains unchanged while the structure of the coenzyme is changed
