The concentration of a biomolecule inside a rod-shaped prokaryotic cell is. 0031 M. Calculate the number of molecules inside the cell, which is 3.2 um long and 1.4 um in diameter.

Since the cell is rod shaped (cylindrical), the formula for volume is:

V = π r^2 h

V = π (0.7 um) ^2 * 3.2 um

V = 4.926 um^3

So the number of moles is:

moles = 0.0031 mol / L * 4.926 um^3 * (1 x 10^-15 L / 1 um^3)

moles = 1.527 x 10^-17 mol

Using the avogadros number, we can calculate the number of molecules:

molecules = moles * Avogadros number

molecules = 1.527 x 10^-17 mol * 6.022 x 10^23 molecules / mol

molecules = 9,195,987.58 molecules

Taking the significant figures of 2:

molecules = 9.2 x 10^6 molecules