## How many bacteria?

About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.

Miss_Me
Garter
Posts: 17
Joined: Wed Jan 03, 2007 6:50 pm

### How many bacteria?

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.

thanks!

Darby
Viper
Posts: 1278
Joined: Thu Mar 02, 2006 5:29 pm
Location: New York, USA
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.......

Belana
Garter
Posts: 8
Joined: Mon Jan 16, 2006 9:48 pm
Contact:
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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