Fig. 3.

AFM images. (a) Condensed mass of brome mosaic virus (BMV), a T = 3 icosahedral virus that infects grasses such as barley. (b) Helical, rod-shaped tobacco mosaic virus (TMV), a ubiquitous pathogen throughout the plant world. (c) Tangles of marine filamentous bacteriophage and their broken fragments scattered on the AFM substrate. (d) Virions of Tipula iridescent virus, a very large icosahedral virus that infects insects. The virions of BMV have a diameter of 30 nm, TMV is about 20 nm in diameter and1,000 nm in length, and the adenovirus and iridovirus have diameters of about 100 nm and 200 nm, respectively.