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Separate Biology · Paper 1 · Higher Tier only

Bacterial numbers in standard form

Key ideas1 of 3

Keep the doubling method

First find the number of divisions and double the starting population that many times. If 1,000 bacteria each divide five times: 1,000 × 2⁵ = 32,000.

At 0, 20, 40 and 60 minutes there are 1, 2, 4 and 8 cells respectively.

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Practice, downloads and sources

Daily 5 · Exam practice · Revision sheet ↓

Higher Tier only. Use alongside the shared B1–B4 lessons.

AQA GCSE Biology 8461 · 4.1.1.6. Original teaching notes, questions and diagrams.