Enzymes Flashcards
What protein structure are enzymes?
Tertiary structure
What do enzymes do?
Catalyse metabolic reactions by reducing their activation energy
When substrates need to join..
Enzyme holds them close together reducing repulsion, so they bond more easily
When substrates need to be broken down..
Bonds are strained so molecule breaks apart more easily
Lock and key model
Where scientists said a substrate fits into the enzyme the same was a key fits into a lock
Induced fit model
Substrate doesn’t only have to be the right shape but also make the active site slightly change shape
How does temperature affect enzyme activity?
Rise in temperature makes enzyme molecules vibrate more, at higher levels, vibrations begin to break down bonds that hold the enzyme in shape, changing the shape of the active site
How does pH affect enzyme activity?
Enzymes have an optimum pH level. Above and below optimum pH H+ and OH- ions can meddle with ionic and hydrogen bonds that hold an enzyme’s tertiary structure together.
How does enzyme concentration affect enzyme activity?
The more enzyme molecules in a solution, the more collisions to form enzyme-substrate complexes formed. This continues to a point where it plateaus due to all enzymes being occupied
How does substrate concentration affect enzyme activity?
The higher the substrate concentration, the faster the reaction. Substrate concentration decreases during a reaction causing a plateau
What is competitive inhibition?
Competitive inhibitor molecules have a similar shape to the substrate molecules. These compete with substrate molecules to bind to the active site and block it so no substrate molecules can fit in
What is non-competitive inhibition?
Non-competitive inhibitors bind to enzymes away from their active site. This causes the active site to change shape, so other substrate molecules can’t bind to it.this is not affected by increasing the substrate concentration.
