Light has wavelength and cross-section. Mass has nothing to do with it, due to quantum.
Unfortunately, Google doesn't give me a reliable answer for the number of molecules in a cell. However, I did find stats for one of Intel's latest processors, the
i7 model codenamed "Gulftown."
That figure in the header, "32nm", refers to the
fabrication process: the "margin" around separate components is supposed to be 32 millionths of a millimetre. This is about 145 silicon atoms across.
Also listed is the transistor count:
1.2 billion. Most bacterium have genomes composed of
millions of molecules, rather than billions. Also keep in mind that growing a bacterium may give you a neuron; Gulftown could probably run all of RF on its own. (Though I'm not sure how much traffic RF gets.)