sciencegcse← Topic extras

Separate Biology · Paper 2 · Foundation + Higher · B6

Reading the base code

Key ideas1 of 3

The sequence carries information

All DNA uses the same four bases, but their order can differ. A sequence of three bases forms the code for a particular amino acid. A longer sequence therefore carries instructions for the order of amino acids in a protein. The information depends on the order, not simply the total number of bases. Two sequences of equal length can carry different information if the bases are arranged differently.

Three successive DNA base groups point to corresponding amino acids, showing how base order specifies amino-acid order. An illustrative model, not a complete gene.

Next: Cloning plants →
Practice, downloads and sources

Daily 5 · Exam practice · Revision sheet ↓

Foundation + Higher · B6. Use alongside the shared B6 lessons.

AQA GCSE Biology 8461 · 4.6.1.5. Original notes, questions and diagrams. Models are simplified; teaching data are illustrative.