Factors Affecting Enzyme Reaction Flashcards
What are the factors of enzyme reaction
Temperature,pH,enzyme concentration,substrate concentration
What happens in an enzyme-controlled reaction when the temperature increases
The rate of an enzyme controlled reaction increase
What does more heat mean
More kinetic energy which results in molecules moving faster
What are the enzymes more likely to do the faster they move
They are more likely to collide with the substrate molecules
What increases with the collision apart from rate when temp. Increases
Energy of collision which means each collision is more likely to result in a reaction
What happens if the energy is too high
The reaction stops and the enzyme denatures
What happens to the bonds if the temperature goes above a certain point
The vibration of molecules breaks some of the bonds that holds the enzyme in shape
What happens if the active site changes shape
The enzyme and the substrate no longer fit together
At what point does the enzyme no longer work as a catalyst
When It denatures
What pH do most human enzymes work at
Ph7
What enzymes are exceptions of the average pH level
Pepsin,which is optimum at pH2
Why is pepsins low pH useful
It can be found in the stomach
Above and below the pH,the H+ and OH- found in acids and alkalis mess up _______
Ionic bonds and hydrogen bonds that hold the enzymes tertiary structure
What happens the more enzyme molecules there are in a solution
The more likely a substrate molecule is to collide with one and form an enzyme substrate complex
So increasing the concentration increases the rate of reaction
What happens if the substrate is limited
There comes a point when there’s more than enough enzyme molecules to deal with all the available substrate, so adding more enzyme has no further affect
What happens the higher the substrate concentration is
The faster the reaction,more substrate molecules means a collision between substrate and enzyme is more likely and so more active sites will be used
What is the saturation point
The point at which so many substrate molecules are present that the active sites are all full so adding more will have no effect
Why is the initial rate if reaction the highest rate of reaction
As the reaction will always decrease unless substrates are added
Enzymes can be prevented by _______
Enzyme inhibitors
What are inhibitors
Molecules that bind to the enzyme that they inhibit .
Inhibition can be competitive or non-competitive
What do competitive inhibitors have a similar shape to
Substrate molecules
What do competitive inhibitors do?
They compete with the substrate molecules to bind to the active site,but no reaction takes place
Instead they block the active site,so no substrate molecules can fit in it
What does how much the enzyme inhibits depend on
The relative concentrations of the inhibitor and substrate
What happens if there’s a higher concentration of substrate
then the substrates chances of getting to an active site before the inhibitor increase
So increasing the concentration of substrate will increase the rate of reaction
What happens if there’s a higher concentration of substrate
then the substrates chances of getting to an active site before the inhibitor increase
So increasing the concentration of substrate will increase the rate of reaction
What are all the steps of a non-competitive inhibitor
1) non competitive inhibitor molecules bind to the enzyme away from its active site
2) this causes the active site to change shape so substrate molecules can no longer bind to it
3) they don’t compete with the substrate molecules to bind to the active site because they are a different shape
4) Increasing the concentration of substrate won’t make any difference to the reaction rate - enzyme activity will still be inhibited
