Enzymes Flashcards
(44 cards)
What do enzyme-substrate complexes reduce?
Activation energy.
Why does an enzyme-substrate complex reduce activation energy?
Because it bends bonds.
What energy do few substrates have without enzymes?
Sufficient energy for the reaction.
What is the shape of the active site before binding in the induced fit model?
Not complementary.
What changes in the enzyme during induced fit?
The active site shape.
What does the change in enzyme shape during induced fit allow?
Substrate to fit / enzyme-substrate complex to form.
What forms when the substrate binds to the enzyme?
An enzyme-substrate complex.
What changes slightly to fit the substrate in the induced fit model?
The active site.
What does the active site do to bonds in the substrate?
Distorts/breaks/forms them.
What does induced fit do to activation energy?
Reduces it.
In the lock and key model, how does the active site behave?
Fixed/rigid shape.
Why does the substrate fit the enzyme in the lock and key model?
Active site is already complementary.
Why does an enzyme catalyse only one reaction?
Its active site has a specific shape.
What fits the enzyme’s active site?
Only one specific substrate.
What happens to enzyme activity as substrate concentration increases?
Increases then plateaus.
Why does enzyme activity plateau at high substrate concentration?
All active sites are occupied.
What forms per second at maximum substrate concentration?
Maximum number of enzyme-substrate complexes.
What happens to rate as enzyme concentration increases?
Increases then plateaus.
Why does increasing enzyme concentration plateau the rate?
Substrate becomes limited.
Why does increasing temperature increase enzyme activity?
More kinetic energy.
What increases due to kinetic energy at higher temperature?
Enzyme-substrate complexes.
What happens to enzymes above optimum temperature?
They denature.
What structure changes when an enzyme denatures?
Tertiary structure.
What happens to the active site when an enzyme denatures?
It changes shape.
