17) Factors Affecting Enzyme Activity Flashcards
- To investigate factors affecting enzyme activity the i_____________ r___________ of r___________ is used to compare conditions.
initial rate of reaction
- An enzyme-substrate complex is formed when a s_________/s collide and bond with an e_________.
substrate/substrates
enzyme
- Factors affecting the rate of enzyme catalysed reactions
1) T
2) _ . _ (acidity)
3) E_________ c_________
4) S_________ c_________
5) I____________
a) c_________ b) n_____________
1) Temperature
2) P.H
3) Enzyme concentration
4) Substrate concentration
5) Inhibitors a) competitive b) non-competitive
- Temperature (Most common in exam)
When the temperature of a solution i____________, the molecules v__________ more
which means:
a. more c_________
b. a higher percentage have the required a___________ e__________
So, more e________ - s__________ complexes are formed.
increases vibrate collisions activation energy enzyme-substrate complexes
- Temperature - Optimum Temperature
Why doesn’t the rate of reaction continue to get faster as the temperature increases?
Because the molecules v__________ more and b__________ i___________ b____________ in the tertiary structure so the bonds being broken are i_____________ and d____________ b____________.
This changes the s_________ of the a___________ s____________ = enzyme d__________
vibrate break internal bonds ionic disulphide bridges shape active site denatured
- P.H (acidity)
The optimum P.H of an enzyme can v_____ depending on its f____________
Different enzymes work in different environments within organisms. Some can work in more acidic environments like the s_________, whilst others work in more alkaline environments like the m_________.
Acids are made up of - H+ (Hydrogen ions)
Alkalis are made up of - OH- (hydroxide ions)
vary
function
stomach
mouth
- P.H (Acidity)
Enzymes have an o__________ P.H. If you i________ or d____________ the P.H away from the optimum, the enzyme activity r_____ will d_________.
This is because the _ _- (alkali) or _+ (acid) will interact with the h___________ b___________ and/or the i_________ b________ which changes the shape of the t______________ structure, which changes the shape of the a_________ s__________ (denatured) resulting in fewer or no e__________ - s___________ complexes being formed.
optimum increase decrease rate decrease OH- H+ hydrogen bonds ionic bonds tertiary structure active site enzyme-substrate complexes
- Enzyme and Substrate Concentration - Enzyme Concentration
As you increase the enzyme concentration the rate of reaction i____________. This is known as a p_________ c___________.
The rate of reaction increases because there are more c____________ between e_________ and s____________ and so more e________-s_________ complexes formed.
increases positive correlation collisions enzymes and substrates enzyme-substrate complexes
- Enzyme Concentration
If the substrate is used up then adding more e___________ will not affect the r________ of r____________.
enzymes
rate of reaction
- Substrate Concentration
As you increase the substrate concentration the rate of reaction i_____________ (p__________ c_________) because there are more c___________ between e_________ and s__________.
Therefore, more e___________-s____________ complexes are formed until all the active sites become o____________.
Now, the l__________ f____________ is the enzyme concentration and adding more substrate will make no difference to the r_______ of r______________.
increases positive correlation collisions Occupied limiting factor rate of reaction
- Inhibitors
An inhibitor is any molecule that reduces or stops a r__________.
reaction
- Inhibitors
Adding a small concentration of an inhibitor will reduce the r__________ of r____________.
rate of reaction
- Inhibitors
If an excess of i____________ is added to a s__________ then the reaction may be prevented c__________!
inhibitors
solution
completely
- Competitive Inhibitors
A competitive inhibitor competes with the s___________.
It fits into the a__________ s__________ of the enzyme instead of the s_______________.
If a competitive inhibitor does fir into the active site, it forms a physical b____________, that prevents the formation of e_________-s__________ complexes.
substrate active site substrate barrier enzyme-substrate complexes
- Competitive Inhibitors
Competitive inhibitors have a l__________ p________ i____________ effect than non-competitive inhibitors.
Catalyzations will take place, but at a s___________ rate as the s_________ is having to compete with the i___________.
N.B. The proportion of substrate to competitive inhibitor will affect how much the r__________ of r_________ changes.
less powerful inhibition slower substrate inhibitors rate of reaction
- Non-competitive Inhibitors
Non-Competitive inhibitors don’t bind to the active site but to a separate part of the enzyme called its a__________ s_________.
Most non-competitive inhibitors bind p__________________.
allosteric site
permanently
- Non-Competitive Inhibitors
Non-Competitive Inhibitors change the shape of the ______________, so no more enzyme-substrate c__________ are formed.
Therefore, adding more s___________ will make no difference.
active site
complexes
substrates
