Enzymes and How They Work - FREE KS3 Biology Worksheet

🧬 Find out how enzymes turn a meal into fuel in hours instead of years in this free KS3 Biology worksheet — no preparation needed, just download and use. Perfect as a lesson starter, homework task or quick revision activity for students aged 11-14.

An enzyme is a biological catalyst: a protein made by living things that speeds up a chemical reaction without being used up. In digestion, these catalysts break large food molecules into small, soluble ones that the body can absorb.

📝 Three questions, 13 marks in total. Question 1 is a multiple choice question on what a biological catalyst is. Question 2 is a five-gap word-bank activity on catalysts, proteins, living things and why they are not used up. Question 3 is a six-mark written answer on why digestion is so much faster with these catalysts, and why the body only needs a small amount of each. The answer key is included. Comes as a PDF and an editable Word file (DOCX).

Full lesson page with the video, quiz and free worksheet: https://inewittall.com/ks3-biology/digestive-enzymes/?utm_source=payhip&utm_medium=listing

Watch the full lesson on YouTube: https://youtu.be/z2yYPx7Sq94

⭐ Want more? The full 100-mark premium worksheet goes deeper into the lock and key model, where each digestive catalyst is made in the body, and how temperature and pH can denature them for good. A complete lesson bundle with the extension pack is also available.

TAGS: KS3 Biology, Enzymes, Digestive Enzymes, Digestion, Biological Catalyst, Free Worksheet, Lesson Starter, Homework, Revision, Year 7, Year 8, Key Stage 3, Science, Answers Included

PRICE: Free

KEY STAGE: KS3

SUBJECT: Biology

FORMAT: PDF + DOCX (editable Word file)