Question 14
HThe small intestine is an exchange surface where dissolved food molecules are absorbed into the blood.
The Figure shows part of the inner surface of the small intestine. The inner surface is covered in villi.
Figure
a.[2]
Explain how the villi increase the rate of absorption of glucose.
b.[2]
Explain how the capillary network in each villus helps to maintain a high rate of absorption of glucose.
c.[2]
In coeliac disease, the villi become flattened.
In one patient, the surface area of the small intestine fell from 30 m2 to 6 m2.
Calculate the percentage decrease in surface area.
d.[2]
Explain why people with untreated coeliac disease often lose body mass.
8.1 Exchange surfaces and diffusion Questions
42 exam-style questions on Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion, covering 8.1.1 Introduction to exchange and transport, 8.1.2 Alveoli adapted for gas exchange, 8.1.3 Factors affecting rate of diffusion, and 8.1.4 Rate of diffusion using Fick's law. Each one has a worked solution and a mark scheme showing where the marks go.