It is interesting to consider the relative sizes of biological components, for example:

1. Hydrogen atom diameter: 0.1 nm
2. Hemoglobin (short side): 5.5 nm
3. RNA Polymerase: ~9 nm
4. Ribosome (Mammalian): 25 nm
5. E.coli: 2μm by 0.8 μm
6. Red blood cell diameter: 6 to 8 μm
7. Hepatocyte diameter: 15 to 20 μm
8. Average diameter of a protein: 5 nm
9. Average concentration of protein in E.coli: 5 to 8 mM
10. ATP concentration in E.coli: 1.3 to 7 mM

More statistics on E.coli

1. Diameter of a transistor: 45 nm