Exam-style Questions: Nutrition and Digestion

1. The drawing shows the human digestive system.

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a) Give the letter of an organ where each of the following is produced:

(i) endopeptidase

(ii) maltase

b) Name the compounds which are produced by the digestion of triglyceride.

c) Describe one role of bile in digestion of triglycerides.

(Marks available: 5)

Answer

 

Answer outline and marking scheme for question: 1

Give yourself marks for mentioning any of the points below:

a) (i) D or E

(ii) F

(max 2 marks)

b) fatty acid and glycerol/monoglyceride

(max 1 mark)

c) EITHER:

emulsification or description e.g. fat drops to droplets;

larger surface area of fat for lipase/digestive enzymes to act on.

OR:

neutralisation of stomach acid;

optimum pH for lipase/digestive enzymes

(max 2 marks)

(Marks available: 5)

 

2. The secretion of digestive juices into the mammalian gut is controlled by the endocrine and nervous systems.

Stimulus that triggers secretion Effect Digestive juice secreted
a) Parasympathetic nerve stimulates salivary gland Saliva
Contact of food with stomach b) secreted Gastric juice
Contact of food with duodenum lining Cholecystokinin secreted c)
Contact of food with duodenum lining d) secreted Alkaline fluid from pancreas

 

What should go in place of the letters a), b), c) and d) to complete the table?

(Marks available: 4)

Source: NEAB 1999

Answer

 

Answer outline and marking scheme for question: 2

a) Sight/smell/taste of food

b) Gastrin

c) Pancreatic juice/bile

d) Secretin

(1 mark for each correct answer)

(Marks available: 4)

 

3. This diagram shows a section through a mollusc:

Exam-style Questions

a) Describe how this mollusc obtains its food.

b) The intestine of this mollusc was used to investigate enzyme activity. The intestine was ground into a paste. An equal amount of this paste was added to a solution of protein and to a solution of starch in separate dialysis tubing. The dialysis tubing was left in separate beakers of water for two hours. The chromatograms show the results of this investigation.

Explain the results of this investigation

(Marks available: 6)

Answer

 

Answer outline and marking scheme for question: 3

Give yourself marks for mentioning any of the points below:

a) Stream of water carries particles/food; in through siphon; Trapped by mucus; Cilia direct/transports particles/water current towards mouth.

(max 3 marks)

b) Mixture contains starch and protein digesting enzymes; Digestion produces soluble products/small molecules/named products; Products diffuse into water/through dialysis tubing.

(max 3 marks)

(Marks available: 6)