Explain the induced-fit model of enzyme action, describing how the active site changes shape and how this lowers the activation energy of a metabolic reaction.

Students investigated the rate of hydrolysis of sucrose by the enzyme sucrase, which breaks down sucrose into glucose and fructose. They prepared several reaction mixtures, each containing:

• sucrase
• pH buffer solution
• sucrose.

Under these conditions, a water molecule is consumed as a reactant in each cleavage. Name the type of chemical reaction catalysed by sucrase.

The students allowed each reaction mixture to run for exactly 4 minutes before stopping it to measure the concentration of glucose produced. Suggest and explain one method the students could have used to halt the reaction immediately at 4 minutes.

The graph below shows the students' results:

Draw on this

Explain the relationship between glucose concentration produced and the initial concentration of sucrose shown in the graph.