miss palmer- enzymes Flashcards
what is an enzyme
type of biological catalyst which is a protien that speeds up the rate of a chemical reaction by lowering activation energy.
how do enzymes act as biological catalyst
it speeds up reaction without actually being used up in the reaction
found in living organisms that catalyse metabolic reactions
lowers activation energy
what are intracellular enzymes
works inside the cell to catalyse the reaction of hydrogen peroxide to be broken-down into oxygen and water.
if this doesn’t happen hydrogen peroxide is the toxic by-product of several cellular reactions so kills cells.
what are extracellular enzymes
works outside of cell in the human digestive system.
amylase is found in saliva so catalyses the break-down of starch into maltose in the mouth
structure of enzymes
globular proteins which have an active site determined by tertiary structure that complementary substrate binds to.
what is an induced fit
activation energy is lowered so speeds up the rate of reaction so more substrates bind making a substrate complex.
the substrate complex changes the shape slightly so this locks substrate in tightly.
how does temperature effect enzyme activity
higher temp, more kinetic energy, molecules move faster so makes substrate more likely to collide with active site until optimum temperature is reached as if temp gets to high reaction will stop as bonds break from too much vibration.
what is a temperature coefficient
the Q10 value for a reaction shows how much the rate of reaction changes when temperature it is raised by 10 degrees.
how does PH affect enzyme activity
the optimum PH is the PH at what the reaction works best.
most enzymes work best at PH7
too much above/below the H+ and OH- ions can break which disrupts the tertiary structure. this could change shape of active site so it denatures.
how does enzyme concentration effect enzyme activity
the more enzyme molecules in a solution the more likely they are to collide and form an enzyme substrate complex
however if all substrates have been used up it will have no further effect this is called the saturation point so enzyme concentration is the limiting factor
what is the saturation point
where all active sites have been used up.
what does denatured mean
active site changes shape so substrate can’t fit in.
what is a control, independent, dependant variable
control- keep same
independent- changes
dependant- measure
only one variable can be changed at once.
What is a co factor
Only works if there are another non-protein substance bound to them
What are inorganic cofactors
Help bind the enzyme and substrate
together
Not used up or changed
E.g. chloride ions are cofactors for amylase
