MetabolismIB MYP Sciences: Topic test

1. 1
   A doctor in Kathmandu examines a child who has soft, bowed legs. The child's diet is mostly rice, with little milk, fish or eggs, and the child spends most of the day indoors.

   (a)

   Which nutrient group in the rice provides most of the child's energy?

   [1 mark]

   • AProtein
   • BCarbohydrate
   • CVitamins
   • DFibre

   (b)

   Which food test shows that a sample of fish contains protein?

   [1 mark]

   • AAdd iodine solution
   • BHeat with Benedict's solution
   • CAdd ethanol, then water
   • DAdd biuret reagent

   (c)

   Name the deficiency disease the child is most likely to have, and explain how the child's diet is likely to have caused it.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A surgeon in Bogotá removes a patient's gall bladder because of painful gallstones. After the operation the patient is told to eat less fatty food.

   (a)

   Where is bile made?

   [1 mark]

   • ALiver
   • BGall bladder
   • CPancreas
   • DStomach

   (b)

   What does bile do to the fat in food?

   [1 mark]

   • ABreaks it down into amino acids
   • BAbsorbs it into the blood
   • CEmulsifies it into small droplets
   • DTurns it into starch

   (c)

   Explain how bile helps lipase to digest fat in the small intestine.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A cook in Manila finds that jelly made with fresh pineapple never sets. The jelly is made from gelatine, which is a protein, and fresh pineapple contains an enzyme that is a protease. Jelly made with tinned pineapple, which was heated to 100 °C when it was canned, sets normally.

   (a)

   Explain why the protease in pineapple can digest gelatine but cannot digest starch.

   [3 marks]

   (b)

   Explain why jelly made with tinned pineapple sets normally.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A school in Perth holds a health week. In one activity, two students compare how quickly their pulse returns to normal after exercise. Student X is a trained swimmer. Her resting pulse is 58 beats per minute. After running on the spot for three minutes her pulse was 138 beats per minute, and it took 4 minutes to return to 58. Student Y does little exercise. His resting pulse is 76 beats per minute. After the same exercise his pulse was 172 beats per minute, and it took 9 minutes to return to 76. In another activity, students discuss a proposal to ban smoking in all public parks and outdoor cafés.

   (a)

   Describe the pattern in the results, explain it, and evaluate how far the results show that swimming training makes a person fitter.

   [6 marks]

   (b)

   Evaluate the proposal to ban smoking in public parks and outdoor cafés. Consider the health, social and economic effects, and reach a justified conclusion.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   A respiratory nurse in Lima explains to a patient that, in a lung disease called emphysema, many of the walls between neighbouring alveoli break down, leaving fewer, larger air spaces. The patient feels out of breath even when walking slowly.

   (a)

   Which gas diffuses from the air in the alveoli into the blood?

   [1 mark]

   • ACarbon dioxide
   • BNitrogen
   • COxygen
   • DWater vapour

   (b)

   Which tube carries air from the trachea into one lung?

   [1 mark]

   • ABronchus
   • BBronchiole
   • COesophagus
   • DAlveolus

   (c)

   Explain why the patient feels out of breath even when walking slowly.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   A paramedic in Johannesburg treats two patients. The first has a deep cut in an artery in his arm, and bright red blood spurts out in pulses. The second has a cut in a vein in his leg, and dark red blood flows out steadily and slowly.

   (a)

   Which statement explains why the blood spurts out in pulses from the cut artery?

   [1 mark]

   • ABlood in an artery has just passed through the capillaries
   • BThe artery has a wide space inside, so blood flows quickly
   • CThe artery contains valves that open and close
   • DThe heart forces blood into the artery at high pressure with each beat

   (b)

   Which feature of veins helps blood to flow back to the heart?

   [1 mark]

   • AThick muscular walls
   • BValves that stop blood flowing backwards
   • CWalls that are one cell thick
   • DPulses of high pressure

   (c)

   Describe two ways in which capillaries are adapted for exchanging substances with body cells.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A child in Lusaka has severe diarrhoea caused by an infection, and passes large amounts of watery faeces. A health worker gives the child an oral rehydration drink containing water, glucose and mineral salts.

   (a)

   Explain why severe diarrhoea is dangerous, with reference to the function of the large intestine.

   [3 marks]

   (b)

   Describe the journey of a glucose molecule in the drink from the small intestine to a muscle cell, and say what happens to it there.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   A science club in Santiago, Chile, is investigating how the body digests fat. The club has milk (which contains fat), lipase solution, dilute sodium carbonate solution (an alkali), phenolphthalein indicator, which is pink in alkaline conditions and colourless in acid, and water baths. Chile has also introduced black warning labels on foods that are high in fat, sugar or salt, and has banned advertising of these foods to children.

   (a)

   The club wants to find out how temperature affects the rate at which lipase digests fat. Design an investigation. Include a hypothesis with a reason, the variables, the method including how the rate will be measured, and a safety precaution.

   [6 marks]

   (b)

   Evaluate Chile's policy of warning labels and advertising bans on foods high in fat, sugar or salt, and reach a justified conclusion.

   [6 marks]

   Total for question 8: 12 marks

End of questions