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Microbes · Chapter 4: Bacterial growth

Year 11 SCX · About 16 minutes with activities · Turn your sound on

Chapter 4 · Bacterial growth
Doubles every 20 minbinary fission
1 day = 72 doublingsabout 5 × 10²¹ cells

Chapter 4 recap

  • Growth curve: log of number of bacteria against time. Lag (adjusting) → exponential (binary fission, food plentiful) → stationary (formed = dying) → death (toxic waste, no nutrients).
  • Ideal conditions: nutrients, optimum temperature (enzymes work fastest), moisture (water, osmosis), the right pH, oxygen unless anaerobic, and space.
  • Growth stops because food runs out, space runs out and toxic waste builds up. Extremophiles: thermophiles, halophiles, acidophiles, xerophiles.
  • Next: Chapter 5 · Fungi and viruses

Could one bacterium really bury the Earth?

Chapter 4 · About 16 minutes · sound on

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