chapter 4

Question 1

features of enzymes

Answer 1

proteins
reactions reversible
specific
reusable
catalysts
speeds up, not create
end in ase
act on entire biochemical pathways

Question 2

two models for enzyme action

Answer 2

1. lock and key - enzyme binds to a substrate like a jigsaw puzzle, they are complementary
2. they are complementary but the enzyme slightly changes shape to bind better to the substrate

Question 3

impact of temperature on enzymes

Answer 3

below tolerance - enzyme is inactive, but this is reversible as it just doesnt have enough kinetic energy
above tolerance - protein becomes denatured, a conformational change

Question 4

impact of ph on enzymes

Answer 4

too low - enzyme becomes denatured
too high - enzyme becomes denatured
within tolerance range - enzyme works more efficiently as it gets closer to the optimum ph

Question 5

impact on enzyme concentration

Answer 5

continuously increases rate of reaction as it increases, until there is more enzyme than substrate.

Question 6

impact of substrate concentration

Answer 6

increases as concentration increases UNTIL the point of saturation - the amount of enzymes means the rate of reaction cant increase

Question 7

similarities and differences between competitive and non competitive inhibition

Answer 7

both decrease enzyme activity
competitive binds to the active site ‘competing’ against the substrate
non competitive binds to the allosteric site and conformational change to the active site occurs

Question 8

what makes competitive inhibition irreversible/reversible?

Answer 8

weak bonds mean the inhibitor is removable, the inhibition is irreversible when the bonds are strong

Question 9

compare cofactors and coenzymes

Answer 9

they both help the enzyme change to enable it to carry out its function
cofactors are non-protein, eg ions
coenzymes are organic molecules