Nutrients and food testsIB MYP Biology: Mind map

Exam questions on Nutrients and food tests

1. A 15-year-old girl in Doha eats very little red meat or green vegetables. She feels tired all the time, and her doctor finds that she has anaemia.
   Explain why a lack of iron makes the girl feel tired.2 marks
2. Sailors on long sea voyages in the 1700s, who ate no fresh fruit, often developed bleeding gums and wounds that would not heal. Today, some children whose diets contain too little vitamin D develop soft, bent leg bones.
   Explain why a diet low in vitamin D leads to soft bones.2 marks
3. A student has four unlabelled food samples, W, X, Y and Z, each mixed with water. She tests each one with iodine solution, with Benedict's solution (heated in a water bath), with biuret solution, and with the ethanol emulsion test. Sample W turns blue-black with iodine and gives no other change. Sample X turns brick-red with Benedict's solution and purple with biuret solution, and gives no other change. Sample Y gives a cloudy white layer in the ethanol emulsion test and no other change. Sample Z gives no change in any test.
   State the nutrient or nutrients present in samples W, X and Y.3 marks