Trypsin is an enzyme which catalyses the hydrolysis of casein, a protein found in milk. Milk that contains casein has a cloudy, white appearance. As the casein is hydrolysed by trypsin, the milk changes in appearance to a clear (transparent), colourless solution. A student carried out an experiment to investigate the effect of enzyme concentration on the rate at which trypsin hydrolyses casein. The student added a solution of trypsin to a sample of milk and recorded the time taken for the milk to become transparent. The student repeated the experiment with different concentrations of trypsin. All other variables were kept constant. Fig. 5.1 shows the results from the experiment. Trypsin has the potential to be used in a wide range of industrial processes. The use of immobilised enzymes in industrial processes has many advantages. Scientists investigated the effect of temperature on the activity of trypsin immobilised on the surface of a material and trypsin free in solution. Table 5.1 shows the results of the investigation. Table 5.1 (i) State a reason for the difference in percentage of maximum activity of immobilised trypsin and trypsin free in solution at $$$25^{\circ} \mathrm{C}$$$. ....................................................................................................................................... . ....................................................................................................................................... . ................................................................................................................................. (ii) Suggest and explain why the percentage of maximum activity of immobilised trypsin at $$$55^{\circ} \mathrm{C}$$$ is higher than the percentage of maximum activity of trypsin free in solution at $$$55^{\circ} \mathrm{C}$$$. ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . .................................................................................................................................

Biology

IGCSE&ALevel

CAIE

Exam No：9700_w24_qp_21 Year：2024 Question No：5(b)

Answer:

Knowledge points:

3.2.1.1 temperature

3.2.1.2 pH (using buffer solutions)

3.2.1.3 enzyme concentration

3.2.1.4 substrate concentration

3.2.1.5 inhibitor concentration

3.2.2 explain that the maximum rate of reaction (Vmax) is used to derive the Michaelis-Menten constant (Km) which is used to compare the affinity of different enzymes for their substrates

3.2.3 explain the effects of inhibitors, both competitive and non- competitive, on the rate of enzyme activity

3.2.4 investigate the difference in activity between an enzyme immobilised in alginate and the same enzyme free in solution, and state the advantages of using immobilised enzymes

Answer:

Knowledge points:

Solution:

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