Enzymes Flashcards
What are anabolic reactions?
Reactions that build up molecules
What are catabolic reactions?
Reactions that break down molecules
What is metabolism?
The sum of all the anabolic and catabolic reactions
What is a catalyst?
A substances that speeds up the rate of a reaction without changing the produced substances
What is a metabolic pathway?
A sequence of enzyme controlled reactions
What is specificity?
When an enzyme can only catalyse specific reactions
What is the substrate?
The molecule the enzymes works on
What is a product
Molecule produced by enzyme
What is the induced fit hypothesis?
That the substrate and active site are only fully complimentary after the substrate is bound
How do enzymes catalyse a reaction?
They lower the activation energy
How does low temperature affect rate of reaction?
The rate of reaction is low because the particles have very little kinetic energy and therefore there are less successful collisions and less product formed
How does the optimum temperature affect rate of reaction?
The rate of reaction is fast because the enzymes and substrates have a lot of kinetic energy and therefore there are more successful collisions
How does high temperature affect rate of reaction?
The rate of reaction is low because the enzymes denature as the bonds holding the proteins in place break and cause the active site to change shape. Therefore there are less enzymes to catalyse the reaction so there are less successful collisions
How does low pH affect rate of reaction?
The rate of reaction is low because there is a higher concentration of H+ ions which means that the R groups are less able to interact so the active site of the enzymes changes shape. Therefore there are less enzymes to catalyse the reaction so there are less successful collisions
How does the optimum pH affect the rate of reaction?
The rate of reaction is fast because the conc. of H+ ions is perfect for the active site of the enzymes therefore there is a higher frequency of successful collisions
How does high pH affect the rate of reaction?
Rate of reaction is low because there are more OH- ions present which causes the R groups to interact less and therefore the active site changes shape. So, there are less successful collisions
How does low substrate concentration affect the rate of reaction?
The rate of reaction is low because there are less substrates in the same area and therefore there are less successful collisions
How does the optimum substrate concentration affect the rate of reaction?
The rate of reaction is fast because there are more substrates in the same area which means there are more successful collisions
How does high substrate concentration affect the rate of reaction?
The rate of reaction is constant because all of the active sites are occupied by substrate particles
How do competitive inhibitors affect enzyme function?
The molecule has a similar shape to the substrate of the enzyme so it competes with the substrate for the active site. This blocks the substrate from binding to the active site. This results in less successful collisions and a lower rate of reaction at LOW substrate concentration
How do non- competitive inhibitors affect enzyme function?
The substrate can still bind to the active site. However, the inhibitor attaches onto the enzyme and changes the shape of the active site so induced fit cannot occur. This results in less successful collisions and therefore reduces the rate of reaction.
Why does the rate of reaction never meet the V Max with non-competitive enzymes?
Because the enzyme and substrate still have a lower frequency of successful collisions because the enzymes with inhibitors do not convert substrate to product
Why can the rate of reaction with competitive enzymes reach the V Max at higher concentration?
Because the inhibitor is out-competed by the substrate and therefore the rate of reaction can increase to the V Max
What is a cofactor?
A non-protein chemical compound or metallic ion that is required for an enzyme’s activity as a catalyst
What is a coenzyme?
Cofactors which are organic- carbon based
Where are coenzymes derived from?
They are often derived from vitamins
How are enzymes named?
They are classified according to the type of chemical reactions that they catalyse. For example, hydrolases are enzymes that hydrolyse reactions.
