AS- Topic 2:Enzymes Flashcards
What is an enzyme?
Biological catalyst, it speeds up the rate of metabolic reactions without undergoing permanent change
What makes an enzyme specific to one reaction?
The substrate is complimentary to the active site of the enzyme
What is a cofactor, and what does it do to an enzyme?
A non protein substance that binds to the enzyme which modifies the active site of the enzyme
What is a coenzyme and what does it do to an enzyme?
A non protein molecule that temporarily attaches to allow the enzyme to function
What is the main difference between the lock and key hypothesis, and the induced fit hypothesis?
In the induced fit hypothesis the active site isn’t an exact fit for the substrate, instead it’s more flexible and moulds itself around the substrate
How do enzymes affect activation energy?
It reduces it so the reaction can happen at a lower temp
What 4 factors affect enzyme activity?
Substrate concentration
Enzyme concentration
Temperature
pH
What are the two types of inhibitors?
Competitive and non competitive
How to competitive inhibitors work?
They have a similar shape to the substrate so they compete with the substrate for a place in the active site
How to non-competitive inhibitors work?
Bind to the allosteric site, which changes the overall shape of the enzyme so the substrate can’t bind to the active site
Which is more effective, competitive or non-competitive inhibitors?
Non-competitive as they decrease enzyme activity even if substrate concentration increases
What is adsorption?
The enzyme is attached via weak chemical bonds to structures such as glass beads
A problem is that they are detached relatively easily from the material
What is entrapment?
This is when a enzyme is trapped within a polymer such as alginate beads, the presence of the polymer reduced the rate of diffusion for substrates and products
What is encapsulation?
This is when enzymes are held in a selectively permeable membrane, the mesh can also reduce the rate of diffusion of substrates/products
What is cross linkage?
This is when covalent bonding is used to attach the enzyme to a matrix such as Cellulose fibres, can reduce the rate of diffusion for substrate/product. A problem is that some of the enzymes active sites may not be available
