Enzymes Flashcards
(13 cards)
1
Q
What are enzymes?
A
Enzymes are biological catalysts
2
Q
Describe what it means by normal enzyme reaction rate
A
- every active site is saturated
- the rate of reaction is at its highest
- there is no increase in rate of reaction
3
Q
Describe what a competitive inhibitor does
A
- binds to the enzyme’s active site and slows down the process
- will soon find an active site
4
Q
Describe what it is meant by a non-competitive inhibitor
A
- The shape of the active site changed due to the non-competitive inhibitor being bound to an allosteric site
- prevents enzyme substrate complexes from forming
- reaction cannot reach the same point
- non-competitive inhibitors have changed the shape of some active sites
- increasing concentration of active sites does not decrease the effect of the inhibitor
5
Q
Describe what it is meant by a low substrate concentration
A
- too few substrate molecules to occupy all of the active sites
6
Q
Describe what it is meant by high substrate concentrations
A
- allow all enzyme molecules to bind with substrate
- rate of reaction is at the maximum
7
Q
Describe what it is meant by excess substrates
A
- reaction levels off
- enzyme molecules active sites are occupied
- E - S complexes cannot be formed
8
Q
Describe the induced fit model
A
- when substrate and enzyme’s active site interact
- the enzymes active site is flexible, there it’s able to mould around the substrate, changing shape, so that it is complimentary to the substrate
- this strains the substrate, therefore distorts particular bonds and lowers activation energy
- enzyme substrate complexes are formed
9
Q
How to calculate the rate of reaction?
A
Rate = difference in y / difference in x
10
Q
Describe the basic lock and key model
A
- the enzymes active site is rigid
- the shape of the substrate is complimentary to the shape of the enzyme’s active site
- this allows the substrate to bind exactly with the enzyme’s active site
- enzyme - substrate complexes are formed
11
Q
How does temperature affect the rate of reaction?
A
- more kinetic energy, meaning more collisions
- further rise causes H bonds and other bonds in the tertiary structure to break
- active site changes = substrate fits less easily
- very high temp would denature the enzyme, so that it is unable to function
12
Q
How does pH affect the rate of reaction?
A
- enzymes have optimum pH
- change away from the optimum affects rate
- change in pH alters charges on amino acids that make the active site - substrate can no longer bind
- large pH can cause hydrogen bonds and ionic bonds in tertiary structure to break
13
Q
Equation for calculating pH
A
pH = - log 10 [H+]
