IGCSE Biology glossary
Absorption
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
The movement of digested food molecules from the small intestine into the blood (or lymph in the case of fats). Small soluble molecules such as glucose and amino acids pass through the villus wall into blood capillaries by diffusion and active transport.
What to include in an exam answer
Absorption requires molecules to be small and soluble. Large insoluble molecules cannot pass through the intestine wall. State that absorption occurs in the small intestine, not the stomach.
Example in context
Explain why food must be digested before it can be absorbed (2 marks): Food molecules such as starch and protein are too large and insoluble to pass through the wall of the small intestine. Digestion breaks them into smaller soluble molecules (like glucose and amino acids) that can be absorbed.
Related syllabus topic
Human nutrition