Biological molecules- Enzymes Flashcards
How does an enzyme-substrate complex lower activation energy
- When substrate molecules attach to the enzyme they are held close together so reducing repulsion and can bond more easily
- Fitting into the active site puts a strain on substrate bonds so the substrate breaks easily
What is the lock and key theory
The substrate fits the enzyme
What is the induced fit model
The substrate makes the active site change shape so that it can fit
What is an enzymes’s shape determined by
By the enzymes tertiary structure
What can an enzymes tertiary structure be altered by
PH or temperature
How does temperature affect enzyme activity
Increase in temp makes the enzyme molecules vibrate and collide more due to more KE however if the temperature goes above a certain level the vibration breaks down some of the bonds and so the active site changed shape and the substrate can’ fit. The enzyme is now denatured.
How does PH affect enzyme activity
A PH different to an enzymes optimum PH can also denature the enzyme
How does enzyme concentration affect rate of reaction
The more concentration means more collisions however if the amount of substrate is limited then adding more concentration no longer becomes not effective
How does substrate concentration affect the rate of a reaction
High substrate concentration means more collisions between substrate and enzyme so more active sites will be used however once an enzyme has become saturated and all the active sites are full adding more conc is no longer effective
What is a competitive inhibitor
They have a similar shape to the substrate molecules and so compete with it to bind to the active site but no reaction happens as instead the competitive inhibitor blocks the active site so no substrate can fit
What is a non-competitive inhibitor
They bind to the enzyme away from its active site so the active site changed shape and the substrate molecules no longer bind
