Fig. 2.1 shows the disaccharide lactose, which is found in milk. [Figure 2.1]

1. (a)Name the type of bond that joins the two monosaccharides in lactose.[1]
2. (b)(i)The enzyme lactase catalyses the breakage of the bond between the two monosaccharides in lactose. Name the type of reaction that breaks this bond.[1]
3. (b)(ii)Some people do not produce the enzyme lactase, so cannot digest lactose. The presence of lactose in the lumen of the intestine reduces the volume of water absorbed into the blood, resulting in diarrhoea. Suggest why the presence of lactose in the intestine reduces the volume of water absorbed.[2]
4. (c)(i)Enzymes, such as lactase, are often immobilised for use in the food industry. A scientist carried out an investigation to determine the effects of temperature on the activity of lactase when it was immobilised and when it was free in solution. The scientist produced alginate beads containing lactase for use in this investigation. The beads varied in size. The scientist selected small beads for the investigation and put them into a glass column. Suggest the advantage of using small beads rather than large beads.[2]
5. (c)(ii)Fig. 2.2 shows the results of the investigation to determine the effects of temperature on the activity of lactase when it was immobilised, I, and when it was free in solution, F. With reference to Fig. 2.2, compare the effect of temperature on the activity of immobilised lactase, I, and lactase free in solution, F.[3]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.