Human digestive systemIB MYP Biology: Mind map

Exam questions on Human digestive system

1. A man in Nairobi has a gallstone that blocks the tube carrying bile from his gall bladder to his small intestine. After eating a meal of fried chicken and chips he feels sharp pain and later passes pale, greasy faeces.
   Explain why the man's body digests fat more slowly while the bile duct is blocked.2 marks
2. A student in Mumbai builds a model of the gut wall. She fills a 10 cm length of Visking tubing (a partially permeable membrane) with a mixture of starch solution and glucose solution, ties both ends and places it in a beaker of distilled water at 37 °C. After 30 minutes she tests the water in the beaker. Benedict's solution turns brick-red when heated with it, but iodine solution stays orange-brown.
   The student now repeats the investigation at 20 °C, 37 °C and 50 °C to find how temperature affects how quickly glucose leaves the tubing. Identify the independent variable and state one variable she must control.2 marks
3. In coeliac disease the lining of the small intestine is damaged and the villi become flattened. A teenager in Sao Paulo with untreated coeliac disease loses weight and feels weak even though she eats plenty of food.
   Explain why she loses weight even though she eats plenty of food.3 marks