IGCSEBiologyCambridge (CIE)Revision Notes7. Human NutritionHuman Diet & DigestionEnzymes in Digestion

Enzymes in Digestion (Cambridge (CIE) IGCSE Biology): Revision Note

Exam code: 0610 & 0970

Written by: Lára Marie McIvor

Reviewed by: Jenna Quinn

Updated on 26 August 2026

Enzymes in digestion

Amylases

Amylases are produced in the mouth and the pancreas (secreted into the duodenum)
Amylases digest starch into smaller sugars

Diagram showing the breakdown of a chain of a starch molecule into individual simple sugar molecules, illustrating enzymatic starch digestion — **The digestion of starch**

Proteases

Proteases are a group of enzymes that break down proteins into amino acids (opens in a new tab) in the stomach and small intestine (with the enzymes in the small intestine having been produced in the pancreas)

Diagram showing protease enzymes breaking a protein molecule represented by a chain of amino acids joined together, into individual amino acid molecules. — **The digestion of proteins**

Lipases

Lipase enzymes are produced in the pancreas and secreted into the duodenum
They digest lipids into fatty acids and glycerol

Diagram showing lipase enzyme breaking a lipid molecule into its products: glycerol and three fatty acid molecules. — **The digestion of lipids**

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Author: Lára Marie McIvor

Expertise: Content Creator

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

Reviewer: Jenna Quinn

Expertise: Content Creator

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.