Lactase is used in the food industry to produce lactose-free milk. Explain why lactose-free milk is beneficial to some people, and describe how lactase is used to produce it.

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

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

Model answer (4 marks)

Lactose‑free milk is beneficial because some people are lactose intolerant.

Lactose‑intolerant people can safely consume the milk; it does not cause them digestive problems.

Lactase is added to milk and it breaks down lactose.

Lactose is broken down into glucose and galactose.

Examiner tips

Use the exact phrase "lactose‑intolerant" and mention "digestive problems" to gain full marks.
Show the two-step process: lactase added → lactose → glucose + galactose.
Keep the answer concise and to the point, matching the four marking points.

Common mistakes

Using vague terms like "people with milk problems" instead of "lactose‑intolerant".
Omitting the final step of lactose conversion to glucose and galactose.
Writing extra sentences that are not required by the question.

Mark scheme (4 marks)

Lactose-free milk is beneficial because some people are lactose intolerant
Lactose-intolerant people can safely consume the milk / it does not cause them digestive problems
Lactase is added to milk and it breaks down lactose
Lactose is broken down into glucose and galactose

Key terms in this question

lactase · lactose