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Some hospital patients suffer from diarrhoea caused by infection with the bacterium Clostridium difficile - AQA - A-Level Biology - Question 4 - 2023 - Paper 1
Question 4
Some hospital patients suffer from diarrhoea caused by infection with the bacterium Clostridium difficile. The C. difficile bacteria release toxins. These toxins cau... show full transcript
Worked Solution & Example Answer:Some hospital patients suffer from diarrhoea caused by infection with the bacterium Clostridium difficile - AQA - A-Level Biology - Question 4 - 2023 - Paper 1
Step 1
Explain why the damage to the cells lining the ileum reduces absorption of the products of digestion
Answer
The damage to the cells lining the ileum leads to a reduced surface area due to the loss of microvilli. Microvilli are small projections that increase the surface area for absorption. A smaller surface area results in less effective absorption of nutrients, such as amino acids and glucose, from the products of digestion.
Step 2
Explain why the damage to the cells lining the ileum reduces absorption of water
Answer
The damage also results in a decreased water potential in the ileum compared to the lumen. As a consequence, water moves out of the cells and into the ileum by osmosis. This osmotic imbalance can lead to increased water loss into the intestinal lumen, contributing to diarrhoea.