Question

The concentration of a biomolecule inside a rod-shaped prokaryotic cell is 0.0037 m. calculate the number of molecules inside the cell, which is 4.1 μm long and 0.9 μm in diameter.

Answer 1

First, let calculate the volume of the rod shaped-bacteria:

S = length of the bacteria * surface of its side = 4.1 * (0.45 *0.45 * 3.14) = 2.6 µm3

Now, let's convert the moles into molecules (with Avogadro's law):

0.0037mol/L = 0.0037 * 6.023 *10^23 = 2.22 *10^21 molecules / L

Now let's convert The volume and the concetrnation into µm3 (molecules / µm3)

1 L = 1 dm3 = 1000 cm3 = 1000000 mm3 = 10^9 µm3

so 2.22 *10^21 molecules / L = 2.22 10^ 12 molecules / µm3

The answer is  2.22 10^ 12 molecules / µm3