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GCSE Biology · key term
A region surrounding an antimicrobial disc where bacteria have not grown.
Used by OCR
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Calculating AreasAfter incubation, bacteria may grow across the plate but fail to grow near the disc, leaving a clear zone.
A circular region around an antibiotic disc in which there is no visible bacterial growth.
Unless the question explicitly asks for the area excluding the paper disc, use the radius of the whole circular clear zone in .
A clear zone is measured across its widest part through the centre. The antibiotic disc is normally included in the measured diameter of the whole clear zone.
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