mass of bacteria

Nicholas Landau njl2q at
Mon Apr 8 23:57:13 EST 2002

The largest viruses are bigger than bacteria?  Which virus?  I never heard
that (but then, I never studied virology).


Graham Shepherd wrote:

> Smarty <smartman at> wrote in message
> news:3cab7bd6.18969629 at
> > Less than 500 milligrams
> >
> An unusually unhelpful response.
> You can get an approximation by calculating the volume of the organism from
> typical dimensions (eg for E.coli assume it's a cylinder 1 micron long with
> a diameter of 0.5 micron) and assume that the density is the same as water.
> (It is greater, otherwise you couldn't spin them down - but it's probably
> not much greater. You could determine the density on a gradient if it's
> critical).
> A rough calculation indicates that the volume is about 0.2 cubic microns.
> That's 5,000,000,000 per cubic millimeter, or 5,000,000,000,000 per cubic
> cm. Assuming 1 gram per cubic cm, one bacterium weighs about 0.2 picogram.
> Viruses are much more variable in size than bacteria (the biggest viruses
> are bigger than the smallest bacteria). But you could do the same
> calculation for a specific virus.
> GS

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