Enzymes Flashcards
What is the function of an enzyme?
To reduce the activation energy and speed up the reaction without being used up
What is the difference between intracellular and extracellular?
Intracellular enzymes act inside a cell whilst extracellular enzymes act outside
Describe the lock and key model
The tertiary structure has an active site which is exactly complimentary to the substrate
Describe the induced fit model
The active site of an enzyme is similar to that of the substrate. The enzyme fits around it
How is activation energy lowered?
The active site of the enzyme puts strain on the substrate as it molds to its shape, distorting bonds and making them easier to break
How do you measure the rate of reaction?
- Rate = amount of product / time taken
- Rate = 1 / time taken
Why do enzymes produce a curve on a rate of reaction graph?
There is more substrate at the beginning, so there are more ES complexes. However the enzymes become saturated therefore the rate levels off
What effect does temperature have on enzymes?
The higher the temperature, the more energy the substrates and enzymes have to collide and form ES complexes
What happens after the temperature extends over the optimum?
The rate dramatically drops because the enzymes become damaged and no longer complimentary due to the force the substrates collide with
What effect does pH have on enzymes?
Each side of the optimum the enzymes will denature
Why do enzymes denature at different pH levels?
Because the bonds in the tertiary structure are broken and reformed in different places altering the shape of the active site
What effect does substrate concentration have on enzymes?
The higher the substrate concentration, the faster the rate, to a certain point
Why does the substrate concentration not affect the rate after a certain point?
Because all the enzymes are saturated and in use so the rate will equalise
What is the effect of enzyme concentration on the rate?
The rate will increase at a faster rate to a certain point
What happens to the rate after a certain point when the enzyme concentration is increased
The substrates become limited meaning that there won’t be enough substrate to occupy all the enzyme
