IGCSE Biology glossary
Sebum
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
An oily substance produced by sebaceous glands in the skin that helps to waterproof the skin surface and inhibit the growth of some bacteria and fungi.
What to include in an exam answer
Sebum is part of the body's first line of defence against pathogens. Skin acts as a physical barrier; sebum provides a chemical barrier. In defence questions, mention both the physical barrier and the antimicrobial secretions.
Example in context
State one chemical defence mechanism of the skin (1 mark): Sebaceous glands produce sebum, an oily substance that inhibits the growth of bacteria on the skin surface.
Related syllabus topic
Diseases & immunity