Explain how biological washing powders remove food stains from clothing at low washing temperatures.

Cambridge International IGCSE Biology (0610) — 21.1 Biotechnology and genetic modification · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Biological washing powders contain enzymes such as proteases, lipases and amylases. These enzymes hydrolyse the large, insoluble food molecules that make up the stain – proteins, fats and starches – into smaller, soluble molecules. The soluble products are then easily removed by the water in the wash. Enzymes are sensitive to temperature; they become denatured and lose activity at high temperatures, so low washing temperatures are used to keep the enzymes active and maximise stain removal.

Examiner tips

  • Mention the specific enzymes (proteases, lipases, amylases).
  • Explain the hydrolysis of large food molecules into soluble products.
  • State that low temperature prevents enzyme denaturation.
  • Show clear cause–effect sequence.

Common mistakes

  • Omitting the role of enzymes or the need for low temperature.
  • Using vague terms like "chemical action" instead of specifying enzymes.
  • Failing to mention that enzymes break down proteins, fats and starches into soluble molecules.

Mark scheme (4 marks)

  1. Biological washing powders contain enzymes (e.g. proteases, lipases, amylases)
  2. The enzymes break down / digest large, insoluble food molecules (e.g. proteins / fats / starch) into smaller, soluble products
  3. The smaller, soluble products can be washed out / removed easily in water
  4. Enzymes are denatured / stop working at high temperatures, so a low temperature is needed to prevent denaturation / keep the enzymes active

Key terms in this question

biological washing powder

Related

More Biotechnology and genetic modification questions

▶ Try answering this question with AI marking (free) →