Biological molecules 1: Factors affecting enzyme activity Flashcards
What are the factors which affect enzyme activity
Temperature
PH
Substrate concentration
Enzyme concentration
Inhibition
How do low temperatures affect enzyme activity
They lead to slower chemical reactions
How does increasing temperature to an enzyme’s optimum increase enzyme activity
Enzyme activity increases because more enzyme-substrate complexes form because more heat is introduced meaning more kinetic energy supplied to molecules so they move faster - leading to successful collisions between substrate and enzyme
Why does the optimum temperature increase enzyme activity
Because more successful collisions occur between the substrate and the enzyme (forming enzyme-substrate complexes)
How does increasing temperature beyond optimum affect enzyme activity
It decreases enzyme activity
Why does increasing temperature beyond optimum decrease enzyme activity
Vibrations which are induced by heat breaks the tertiary structure which holds the enzyme in shape meaning its no longer complementary to the substrate as the active site also changes
How does the PH increasing/ decreasing away from optimum affect enzyme activity
It decreases enzyme activity
Why does the PH increasing/ decreasing away from optimum decrease enzyme activity
The H+ ion found in acids and the OH- ion found in alkali’s disrupt the ionic and hydrogen bonds that holds an enzymes tertiary structure, leaving it denatured because the active site changes
How does increasing substrate concentration affect enzyme activity
It increases enzyme activity
Why does increasing substrate concentration affect enzyme activity
More substrate molecules means their is a higher chance of successful collisions from occurring between enzyme and substrates to form enzyme-substrate complexes up to a saturation point
What happens when substrate concentration reaches a saturation point
The substrate becomes a limiting factor because the active site of the enzymes are all full - and increasing substrate concentration had no further effect
How does increasing enzyme concentration affect enzyme activity
It increases enzyme activity
Why does increasing enzyme concentration increase enzyme activity
As enzyme concentration increases so does the chance of a substrate successfully colliding with the one to form an enzyme substrate complex
What happens if a substrate in a solution is limited
Enough enzymes would be able to react with the available substrate with some enzymes to spare
What are the two types of inhibitors
Competitive
Non-competitive
How do competitive inhibitors decrease enzyme activity
It slows down the initial rate of reaction by binding to the active size of an enzyme - temporarily blocking substrates from the enzymes and preventing enzyme-substrate complexes from forming
What do competitive inhibitors bind to
The active site
What do non-competitive inhibitors bind to
The allosteric site (away from the active site)
How do non-competitive inhibitors decrease enzyme activity
It slows down the initial rate of reaction by binding to the allosteric size of an enzyme - permanently blocking substrates from the enzymes and preventing enzyme-substrate complexes from forming
In terms of the rate of reaction - substrate concentration graph, how will a non competitive affect the curve
The initial rate of reaction would be less steep and the curve would have a lower vmax than if the reaction contained no non-competitive inhibitors
In terms of the rate of reaction - substrate concentration graph, how will a competitive affect the curve
The initial rate of reaction would be less steep however the curve would have the same vmax than if the reaction contained no competitive inhibitors
