Chapter 5 - Enzymes

Question 1

Define enzyme.

Answer 1

An enzyme is a biological catalyst that is protein in nature. It speeds up rate of chemical reaction by providing an alternative pathway with lower activation energy required. It remains chemically unchanged after the reaction.

Question 2

Why are enzymes specific in action?

Answer 2

The 3-Dimensional shape of the substrate and the shape of the active site of the enzyme are complementary to each other. The chemical reaction can only be catalysed by a unique enzyme.

Question 3

How does temperature affect enzyme activity?

Answer 3

(Until optimum temp)
Increase in temperature = increase in kinetic energy = enzymes and substrates move more rapidly = more effective collisions = more enzyme-substrate complexes formed = more products formed
(Beyond optimum temp)
Bonds that keep the protein in shape break = Enzymes lose their 3-Dimensional shape and shape of active site (denatured) = Substrates cannot fit into active site = Less enzyme-substrate complexes formed = Less products formed