many proteins are enzymes Flashcards
what is the role of an enzyme
lowers activation energy
biological catalyst in cells (intracellular) and outside of cells (extracellular)
what is the lock and key model
outdated
active site fixed shape
complementary
after successful collision and enzyme substrate complex is formed leading to a reaction
what is the induced fit model
enzyme active site is not completely complementary
active site changes shape as substrate binds and enzyme substrate complex formed
this distorts bonds in substrate leading to reaction
what is the specificity of enzymes
enzymes have a specific tertiary structure and active site
determined by amino acids
active site is complementary to specific substrate
only this substrate can bind to active site
what is the effect of enzyme conc. on rate
increased enzyme conc. = increased rate
more enzyme = more active sites
limiting factor
what is the effect of substrate conc. on rate
increase = increase rate
limiting factor( too few enzyme molecules to occupy all active sites) (all sites saturated)
more successful collisions and complexes
what is the effect of temperature on rate
increase to optimum
increase rate
increases kinetic energy
more collisions and complexes
above optimum decreases rate as enzymes denature- tertiary structure and active site chnages shape
what is the effect of pH on rate
above or below optimum decreases rate
denature- tertiart and active sites chnage shape
bonds break
pH = -log10[H+]
what is the effect of competitive inhibitors on rate
decreases rate
similar shape to substrate
block active site
fewer complexes
increasing substrate conc. reduces effect
what is the effect of non competitive inhibitors on rate
decreases a lot
binds away from active site
tertiary structure changes
cant bind
increasing substrate conc. has no effect
permanent
