1. 1
   A patient who has recently had their gall bladder removed due to gallstones is warned by their doctor that they may experience difficulty digesting fatty foods, since bile can no longer be stored and released into the small intestine in the same way as before.

   (a)

   Before it was removed, what was the normal role of the patient's gall bladder?

   [1 mark]

   • AIt produces bile
   • BIt stores bile before releasing it into the small intestine
   • CIt produces protease enzymes
   • DIt absorbs water from undigested food

   (b)

   Which function of bile explains why the patient may now struggle to digest fatty foods?

   [1 mark]

   • ABile digests starch into simple sugars
   • BBile absorbs fats directly into the blood
   • CBile digests proteins into amino acids
   • DBile emulsifies fats, increasing their surface area for lipase to act on

   (c)

   Describe two roles of bile in the digestive system, and explain why a reduced supply of bile could make it harder for the patient to digest fatty foods.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   After eating a meal containing bread (starch), meat (protein) and butter (lipid), a student traces the digestion of each food type as it passes through the digestive system, noting that different enzymes act on each type of molecule in different parts of the gut.

   (a)

   Which gland produces amylase, the enzyme that begins digesting the starch in the bread?

   [1 mark]

   • ASalivary glands (and pancreas)
   • BGall bladder
   • CLiver
   • DLarge intestine

   (b)

   What are the products formed when protease breaks down the protein in the meat?

   [1 mark]

   • ASimple sugars
   • BFatty acids and glycerol
   • CAmino acids
   • DStarch

   (c)

   Name the enzyme that digests the lipid in the butter, state the products of this reaction, and state where in the digestive system this enzyme acts.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A patient with a condition that damages the villi lining their small intestine is found to have poor absorption of nutrients from their food, despite eating a normal, balanced diet, and their doctor explains that the microscopic structure of the villi is essential for efficient absorption.

   (a)

   Describe the structure of a villus in the small intestine and explain how it is adapted for the absorption of nutrients.

   [3 marks]

   (b)

   Explain why damage to the villi would specifically reduce the patient's absorption of nutrients such as glucose, amino acids and fats, and explain whether you would also expect this damage to affect water absorption.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Early physiologists dissecting the human digestive system mapped out the pathway food takes from the mouth to the anus, and identified the specific roles of each organ and the enzymes and secretions involved in breaking down and absorbing food.

   (a)

   Describe the structure and function of the organs of the human digestive system as food passes from the mouth to the anus.

   [6 marks]

   (b)

   Describe the roles of digestive enzymes, bile and the villi in the digestion and absorption of food, and describe the role of the large intestine.

   [6 marks]

   Total for question 4: 12 marks

End of questions