Enzymes

Question 1

What are the factors that affect enzyme activity ?

Answer 1

Temperature
PH
Substrate concentration
Enzyme concentration
Inhibitors

Question 2

How does temperature affect enzyme activity ?

Answer 2

Too low - not enough kinetic energy for enzymes to move fast enough for frequent successful collisions
Therefore fewer enzyme-substrate complexes
Too high - Enzyme denatures, active site changes shape , no longer complementary to substrate -> no more enzyme substrate complexes can be formed

Question 3

How does PH affect enzyme activity

Answer 3

Too low/high - Too many OH/H ions -> interfere with amino acid charges - bonds in tertiary structure will break
Enzyme denatures, active site changes shape
No longer complementary to substrate
Fewer enzyme-substrate complexes formed

Question 4

Is the optimal pH constant in all enzymes ?

Answer 4

No
E.g. amylase may have an optimal pH leaning alkaline
Proteases may have an optimal pH leaning acidic

Question 5

How does Substrate affect enzyme activity ?

Answer 5

Too low - Substrate is a limiting factor - fewer substrates present to collide with enzymes
Fewer Enzyme-substrate complexes formed
Eventual plateau - constant rate of reaction
Due to enzyme acting as limiting factor
All active sites taken up

Question 6

How does enzyme concentration affect enzyme activity ?

Answer 6

Too low - enzymes are a limiting factor
Insufficient enzymes - active sites are saturated - fewer enzyme-substrate complexes formed
Eventual plateau - constant rate
Empty active sites - not enough substrates
To frequently and successfully collide

Question 7

How does a competitive inhibitor work ?

Answer 7

Similar in shape to substrate
Complementary to active site
Prevention of substrate binding
Enzyme-Inhibitor complex
No enzyme-sub complexes formed

Question 8

Can you overcome a competitive inhibitor ?

Answer 8

Yes
Add more substrate/ increase concentration

Question 9

How does a non-competitive inhibitor work ?

Answer 9

Bind to allosteric site
Changes shape of active site/ tertiary structure
No longer complementary to substrate

Question 10

Can you overcome a non - competitive inhibitor ?

Answer 10

No

Question 11

What goes on the axes of a rate of reaction graph ?

Answer 11

X : axis - Substrate Concentration
Y : axis - Rate of reaction