S3T1: Enzymes Flashcards
How does enzymes speed up rate of reaction?
It lowers activation energy needed to start a reaction
How are enzymes highly specific?
IT has a unique 3d shape (active site) configuration: each chemical reaction is catalysed by a unique enzyme
Enzymes remain chemically unchanged at the end of reaction - purpose
Can be used over and over, required in minute amounts to catalyse large number of reactions
Explain the lock and key model
Enzyme is the lock and substrate is the key
Substrate binds to the specific and complementary active site of enzyme, just like lock and key
active site shape is specifically complementary to enzyme, substrate fits perfectly to active site
enzyme substrate complex formed, enzyme lowers activation energy and catalyses the hydrolysis of substrate into products
products detach from active site, active site is freed up for another reaction
How does temperature affect rate of enzyme reaction?
Temperature increases kinetic energy of enzymes and substrates, collide with each other more frequently, rate of ES complex formed increases, thus increasing rate of products formed (fit perfectly w e/o, bind…)
High temperature, increases vibration of atoms in enzyme, vibration becomes too violent, weak hydrogen bonds in enzyme break, enzyme AS site loses its specific and complementary 3D shape, substrate can no longer bind to enzyme, no longer can form ES complex, denatured, rate of products formed drops drastically.
How does pH affect rate of reaction of enzyme?
Extreme pH (reversible at limits) breaks intact hydrogen bonds between amino acids, enzyme AS site loses its specific and complementary 3D shape, substrate can no longer bind to enzyme, no longer can form ES complex, denatured, rate of products formed drops drastically.
