Enzymes Q/A

Question 1

Explain why the Rate of reaction of enzyme B is low at pH 6 (3)

Answer 1

As the pH changes so does the concentration of H+ ions
It disrupts the ionic bonding holding the tertiary structure together
It affects the charges on the R groups that line the active site so temporary bonding with the substrate may no longer occur
The shape of the active site changes
Enzyme no longer fits
Substrate no longer fit
Less ES Complexes form
Rate is reduced

Question 2

Use your knowledge of protein structure to explain why enzymes are specific and may be affected by non competitive inhibitors

Answer 2

🔱Each enzyme can only combine with one substrate due to their complementary shape
🔱they have a precise tertiary structure which gives them their particular shape
🔱they have a precise primary structure
🔱they have a functional part called the active site which the substrate binds to forming ES complexes
🔱active site has a unique structure
However non competitive inhibitors join to the enzyme not the active site but change the complementary shape so substrate can no longer bind to the active site as the tertiary structure is changed and types of bonding had changed so the enzyme is no longer specific

Question 3

Induced fit and lock and key are two models used to explain the action of enzymes

Describe the induced fit model of enzyme action

Answer 3

When enzyme and substrate are NOT COMPLEMENTARY but enzyme induces or fits to the shape of the substrate to bind together to form ES complexes

Question 4

Describe one way that the lock and key model is different from the Induced fit model BE SPECIFIC BISH

Answer 4

Active site doesn’t change

Question 5

An enzyme catalyses only one reaction explain why

Answer 5

The enzyme has a precise tertiary structure which makes the active site and substrate complementary to each other which bind together to create ES complexes