enzymes Flashcards
what is an enzyme?
a biological catalyst
what is a catalyst?
a chemical which increases the rate of reaction
how do enzymes work? (lock and key theory)
-substrate and enzyme collide
-substrate binds to active site of enzyme, forming an enzyme-substrate complex
-this strains the chemical bonds in the substrate molecules therefore the reaction occurs by an alternate pathway with a lower activation energy
-once the reaction has occurred, the products of the reaction are released as they do not fit the active site
-the enzyme molecule is now free to catalyse the next reaction
how does temperature affect the rate enzyme activity?
as temp increases, enzyme and substrate have more KE, meaning they move faster and so there are more successful collisions
why does pH and temp negatively effect enzymes if they are wrong/ changed?
-proteins held together by forces between parts of the amino acid chain, and high temps and changes in pH disrupt these forces, so the shape changes
when the active site changes due to pH change or temp too high:
-enzyme DENATURED
-active site change means it no longer fits with substrate
what does increasing concentration (adding more substrate or enzyme) do to the rate of reaction?
increase
