Enzymes

Question 1

What is an enzyme

Answer 1

Biological catalyst
Catalyses chemical reactions without being altered or destroyed

Question 2

What is a coenzyme

Answer 2

Heat stable substance which aids enzyme reactions

Question 3

What is a co-factor

Answer 3

non-protein unit needed for a reaction

Question 4

What is an isoenzyme

Answer 4

Enzymes that catalyse same reaction but vary in structure

Question 5

What 3 ways do enzymes lower activation energy

Answer 5

Entropy reduction - correct orientation
Desolvation - Weak bonds replace H+ bonds between enzyme and aqueous solution
Induced fit - Conformational change to fit substrate better

Question 6

In Michaelis-Menten graph what are the units of
Vmax
S
Km

Answer 6

Vmax= Max reaction velocity
S = substrate conc.
Km= substrate conc. when reaction at 1/2 max velocity

Question 7

What is Km

Answer 7

How specific enzyme is for the substrate
Low value = good fit
High value = bad fit

Question 8

What is Vmax

Answer 8

How fast enzyme is at speeding up the reaction
High value= high speed

Question 9

What is Competitive inhibition

Answer 9

Inhibitor binds to active site
Vmax unchanged
Km increases

Question 10

Non-competitive inhibition, what happens to vmax & km

Answer 10

Vmax decreases
Km stays the same