IGCSE Biology Human nutrition topical questions

Match each diet component to its importance.

1. (a)Name the component needed to make haemoglobin.[1]
2. (b)Name the vitamin whose deficiency causes rickets in children.[1]
3. (c)Name the diet component that keeps peristalsis working and prevents constipation.[1]
4. (d)Name the component used mainly for growth and repair of tissues.[1]

The five functions of the digestive system are ingestion, digestion, absorption, assimilation and egestion.

1. (a)Name the function taking place in the mouth when food enters the body.[1]
2. (b)Name the function performed by villi in the ileum.[1]
3. (c)Name the function happening when liver cells build plasma proteins from amino acids.[1]
4. (d)Name the function of the rectum and anus.[1]
5. (e)State one region where chemical digestion of protein happens.[1]

The diagram of a tooth shows: a hard outer coat, a layer beneath it, a central cavity with nerves and blood vessels, and the root held in the jaw.

1. (a)Name the hard outer coat.[1]
2. (b)Name the layer beneath it.[1]
3. (c)Name the cavity containing the nerves and blood vessels.[1]
4. (d)State what happens if the enamel is worn away.[1]

An adult human has four types of teeth in each jaw. The table shows how many of each type are found in the whole adult mouth.

1. (a)Complete the function column for each tooth type.[2]
2. (b)Calculate the total number of teeth in the adult mouth.[1]
3. (c)Explain why the teeth have different shapes.[2]

A student chews a piece of bread for a minute. It begins to taste sweet.

1. (a)Name the enzyme in saliva and its substrate.[2]
2. (b)Explain the sweet taste.[2]
3. (c)Name the enzyme that completes starch digestion in the small intestine, and state where it is found.[1]

A meal contains protein, starch and fat. Describe the digestion of each, naming the enzyme, where it acts and the end products.

1. (a)Starch — enzyme, region, end product.[2]
2. (b)Protein — enzymes, regions, end product.[2]
3. (c)Fat — enzyme, region, end products.[2]

Bile arrives in the duodenum just as acidic stomach contents arrive.

1. (a)Name the organ that makes bile and the organ that stores it.[2]
2. (b)Explain how bile helps lipase digest fat faster.[2]
3. (c)State the pH role of bile in the duodenum.[1]

A 55 g cereal bar provides 220 kcal of energy and contains 8 g of fat.

1. (a)Calculate the energy provided per gram of bar, in kcal per g.[2]
2. (b)Calculate the percentage of the bar’s mass that is fat. Give your answer to one decimal place.[2]
3. (c)Pure fat releases about 9 kcal per g. Calculate the energy from the bar’s fat, and the percentage of the bar’s energy that comes from fat. Give the percentage to one decimal place.[2]

Four patients each show one symptom. Patient A: gums bleed and wounds heal slowly. Patient B: legs bowed and bones soft. Patient C: tired and pale, with little haemoglobin. Patient D: a swollen neck (goitre).

1. (a)Identify the substance missing from the diet of each patient.[4]
2. (b)Name one dietary source of the substance missing from patient C.[1]
3. (c)State which two patients would recover fastest with more sunlight.[1]

Plaque bacteria on teeth feed on sugar. Each time a student eats a sugary snack, the plaque pH stays below 5.5 (the level at which enamel dissolves) for 20 minutes. The student eats three sugary snacks between meals.

1. (a)Calculate the total time the student’s teeth are at risk of decay from these snacks.[1]
2. (b)Explain why dentists advise eating sugar only at mealtimes, even if the total amount of sugar stays the same.[2]
3. (c)State two other ways the student could reduce the risk of tooth decay.[2]
4. (d)Name the hardest substance damaged when the pH stays low.[1]

A patient has part of her ileum removed after surgery. The rest of her digestive system works normally.

1. (a)State two functions the patient may struggle with after the operation.[2]
2. (b)Explain how the villi of the remaining ileum normally maximise absorption.[3]
3. (c)Suggest why the patient is told to eat smaller meals more often.[1]

A person’s daily energy intake is 3000 kcal. Of this, 1200 kcal comes from carbohydrate and 900 kcal from fat; the rest is protein.

1. (a)Calculate the percentage of energy from carbohydrate.[2]
2. (b)Calculate the percentage of energy from protein.[2]
3. (c)A guideline suggests no more than 35% of energy from fat. Calculate this person’s fat energy percentage and state whether they exceed the guideline.[2]
4. (d)State one reason the body still needs some fat in the diet.[1]

The diagram of a villus shows: a wall one cell thick, a network of blood capillaries, a central lacteal, and epithelial cells covered in microvilli. (Supplement)

1. (a)Name the products of digestion absorbed by the capillaries and by the lacteal.[2]
2. (b)Explain how villi and microvilli together speed up absorption.[2]
3. (c)Explain why the wall being one cell thick speeds up absorption.[1]
4. (d)State two reasons why a rich blood supply helps the villus work.[2]

A person’s daily diet is compared with recommended values.

1. (a)Identify the two largest imbalances, using the numbers in the table.[2]
2. (b)State one health risk linked to the excess of fat and energy.[1]
3. (c)Suggest two changes to the diet that would improve it.[2]
4. (d)Calculate the percentage increase in fibre needed to reach the recommendation. Show your working.[2]