OCR GCSE Biology A · J247
Specification B6.2e · Paper 2 (Foundation), Paper 4 (Higher)
Revise: Genetic engineering processA plasmid can carry an antibiotic resistance marker as well as the desired gene. When the bacteria are grown in the presence of that antibiotic, bacteria without the resistance marker do not survive, while those that took up a marker-carrying plasmid can grow.