Describe the role of amylase and maltase in the chemical digestion of starch.

Cambridge International IGCSE Biology (0610) — 7.4 Chemical digestion · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Amylase is an enzyme that hydrolyses the α‑1,4‑glycosidic bonds in starch, producing the disaccharide maltose.
Amylase is present in saliva in the mouth and in pancreatic juice in the duodenum.
Maltase is a membrane‑bound enzyme located on the brush border of the small‑intestine epithelium.
Maltase cleaves maltose into two molecules of glucose, which can be absorbed into the bloodstream.

Examiner tips

Use the exact terms ‘amylase’, ‘maltase’, ‘starch’, ‘maltose’, ‘glucose’, ‘saliva’, ‘pancreatic juice’, ‘small intestine’, ‘brush border’.
Show the sequence: starch → maltose (amylase) → glucose (maltase).
Mention the location of each enzyme to earn the full 4 marks.

Common mistakes

Confusing the order of action (e.g., saying maltase acts before amylase).
Omitting the location of amylase or maltase.

Mark scheme (4 marks)

Amylase breaks down starch into maltose
Amylase is found in saliva (in the mouth) and in pancreatic juice (in the small intestine / duodenum)
Maltase breaks down maltose into glucose
Maltase is a membrane-bound enzyme found in the epithelial cells / lining of the small intestine

Key terms in this question

amylase · maltase · chemical digestion · starch