Biology Forum Microbiology How many bacteria?

last updated by Belana 17 years ago
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    • #7103
      Miss_Me
      Participant

      I was wondering, if a bacteria organism divides once every 20 minutes, how long would it take to produce 2,000,000 (or 2 x 10^6) bacteria cells?

      I’m confused on how i’d work this out because i’m getting a sense of there’s too many numbers to handle, as each cell divides in 2 every 20 minutes.

      please help!

      thanks!

    • #69729
      Darby
      Participant

      The easiest way to work this out is with a table, putting the time intervals next to the total number of cells. You won’t need that big a table, either…

      0 minutes – 1 cell
      20 min – 2
      40 – 4…….

    • #70283
      Belana
      Participant

      x(final) = x(start)*2^n

      n = t (time needed) / T (generation period)

      2000000 = 1*2^n
      log 2000000 = n . log 2
      n = 20,93

      ((20 min = 1/3 h))

      20,93 = t / (1/3)
      20,93 = 3t

      t = 6,97h = cca 6h 58 min

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