# A student leaves a piece of bread in a warm, moist cupboard. After several days, the bread is covered in mould. The mould is a fungus that secretes amylase onto the surface of the bread to obtain nutrients. Explain how the amylase secreted by the mould allows it to obtain nutrients from the bread, and describe what would happen to the amylase if the temperature in the cupboard became extremely high.

> OCR GCSE Biology A: Gateway Science (J247) — B1.2 What happens in cells (and what do cells need) · Explain · 4 marks

> A student leaves a piece of bread in a warm, moist cupboard. After several days, the bread is covered in mould. The mould is a fungus that secretes amylase onto the surface of the bread.

## Mark scheme (4 marks)

1. Amylase is an enzyme that breaks down carbohydrates (starch) in the bread into simple sugars
2. The substrate (starch/carbohydrate) has a complementary shape to the active site of amylase, so it fits into the active site (lock and key hypothesis)
3. At extremely high temperatures, the enzyme denatures
4. Denaturation causes a permanent change in the shape of the active site, so the substrate can no longer fit and the enzyme cannot function

## Key terms

- [amylase](https://www.gradenine.co.uk/glossary/amylase)

## Related

- [Revision notes for OCR GCSE Biology A: Gateway Science (J247)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-leaves-a-piece-of-28fbaced) · Published by Druglandscape Ltd.