A learner examined how starch is digested. Fig. 2.1 shows the apparatus she used. Dialysis tubing is used as a model of a cell membrane. The dialysis tubing material lets small molecules pass through it, but not larger molecules. Test-tubes A and B were arranged as shown in Fig. 2.1 and kept in a water-bath at 37 ^{\circ}C for 30 minutes. The liquid outside the dialysis tubing in test-tubes A and B was checked with Benedict’s solution at 0 minutes and again after 30 minutes. Table 2.1 gives the results.
(a)[6]
Using the information in Fig. 2.1 and Table 2.1, Explain why test-tubes A and B give different results in Table 2.1.
(b)[4]
Complete Table 2.2 by entering the missing enzyme names, substrates and products.
(c)[1]
State the name of the structures that increase the surface area available for absorption in the small intestine.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Benedict’s solution in A stays blue / shows no colour change / gives a negative result” …