3.1.4.2-Many proteins are enzymes Flashcards
(17 cards)
What are enzymes?
Tertiary structure proteins which catalyse reactions
What defines enzymes as a catalyst?
Lowers activation energy
Why is an active site specific and unique in shape?
Due to the specific folding and bonding in the tertiary structure of the protein
Why can a substrate bind to active site?
Complementary shape
What is formed when a substrate binds to active site?
Enzyme-Substrate complex
What is the accepted model for enzyme action?
Induced fit
What does the induced fit model show?
Active site slightly changes shape to mould around substrate to form enzyme-substrate complex, this puts strain on bonds lowering activation energy
What does lock and key model suggest?
The active site is a fixed shape and substrate is complementary
What 4 things can change the rate of enzyme action?
pH,temperature,concentration of substrate, concentration of enzyme
How does temperature affect rate of enzyme action?
Too low-not enough kinetic energy for successful collisions between substrate and active site=fewer enzyme-substrate complex’s
Too high-enzymes denature,active site changes shape,ESC can’t form
How can pH affect rate of enzyme action?
too high or too low will interfere with charges in amino acid in active site which can break bonds holding tertiary structure in place therefore active site shape changes so enzymes denature and fewer enzyme-substrate complexes form
How can substrate concentration affect rate of enzyme action?
Insufficient amount will slow reaction due to fewer collisions between enzyme and substrate
How can enzyme concentration affect rate of enzyme action?
insufficient amount means active site will become saturated with substrate and unable to work any faster
How do competitive inhibitors work?
similar shape to enzyme substrate
binds to active site
blocks substrate preventing ESC forming
How can competitive inhibitors be overcome?
Increasing substrate concentration so substrate and outcompete inhibitor
How do non-competitive inhibitors work?
bones to allosteric site
alters enzyme tertiary structure changing active site shape
substrate can’t bind so ESC can’t form
Explain how the active site of an enzyme causes a high rate of reaction
Lowers activation energy
Induced fit causes active site to change shape
So enzyme-substrate complex causes bonds to break
