IGCSE Biology glossary
DNA
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
Deoxyribonucleic acid, a double-stranded molecule in the shape of a double helix found in chromosomes. DNA carries the genetic code as a sequence of bases (A, T, C, G) that determines the order of amino acids in proteins and therefore controls cell activities.
What to include in an exam answer
Know the base pairing rules: A pairs with T, C pairs with G (complementary base pairing). DNA is found in the nucleus. The sequence of bases codes for the sequence of amino acids in a protein.
Example in context
Describe the structure of DNA (3 marks): DNA is a double helix made of two strands. Each strand is made of nucleotides containing a base. The bases pair in a complementary way: adenine with thymine, and cytosine with guanine.
Related syllabus topic
Inheritance