Theory question 102
Food Substances and Enzymes(a)(i) What is a deficiency disease? (ii) Complete the table below by naming five nutrient dificiency diseases in humans and stating one remedy each for the diseases.
Nutrient dificiency disease | Remedy
(b) Outline a chemical test for. (i) starch in a tuber of yam; (ii) glucose in orange fruit.
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(a)(i) A deficiency disease is a disease caused by lack of (or too little of) a particular nutrient, such as a vitamin, mineral or protein, in the diet.
(ii) Any five, each with its remedy: kwashiorkor – eat protein-rich food (beans, eggs, fish, meat); marasmus – enough protein and energy foods; rickets – vitamin D and calcium (milk, eggs, sunshine); scurvy – vitamin C (oranges, fresh fruit and vegetables); beriberi – vitamin B1 (unpolished rice, whole grains); night blindness – vitamin A (carrots, palm oil, liver); anaemia – iron (liver, green vegetables); goitre – iodine (iodised salt, sea food); pellagra – niacin (vitamin B3).
(b)(i) Peel and cut a slice of yam (or mash some in water); add a few drops of iodine solution; a blue-black colour shows starch is present.
(ii) Squeeze some orange juice into a test tube; add an equal volume of Benedict's solution (or Fehling's A and B); heat in a water bath; a colour change from blue to green, yellow and finally brick-red (orange-red precipitate) shows glucose (reducing sugar) is present.
For each test say what is added, what is done, what is seen and what it shows.