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Edexcel IGCSE Biology 2.29 digestive enzymes

Practise enzyme digestion in the alimentary canal, linking substrates to products and explaining how missing enzymes affect nutrient breakdown.

Syllabus
First assessment 2019
Course
Biology 4BI1

Exam points

  • complete enzyme tables linking amylase, protease and lipase to substrates and products
  • explain how amylase and maltase convert starch through maltose into glucose
  • apply blocked pancreatic ducts or inhibitors to predict reduced digestion of named foods

2.29 Digestive enzymes question 1

[Maximum number: 1]

Pineapple juice contains a protease called bromelain.
A student uses this method to investigate the digestion of solid gelatine protein by bromelain.
- place solid gelatine protein into a test tube up to a height of 5 cm
- mix 5 cm35 \mathrm{~cm}^{3} pineapple juice with 1 cm31 \mathrm{~cm}^{3} of pH 4 buffer
- place 1 cm31 \mathrm{~cm}^{3} of the pineapple juice and buffer solution on top of the gelatine
- leave for one hour in a water bath set to 37∘C37^{\circ} \mathrm{C}
- measure the height of the solid gelatine and use it to calculate the volume of gelatine that has been digested

Repeat the method three more times.
The diagram shows part of the student's method.

Figure for Question 2.29 Digestive enzymes question 1 — Edexcel IGCSE Biology

The table shows the student's results for the volumes of gelatine digested at pH 4 .

Table for Question 2.29 Digestive enzymes question 1 — Edexcel IGCSE Biology

State what substances are produced when the gelatine protein is digested.

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