False-colour transmission electron micrograph of rod-shaped virus particles of tobacco mosaic virus (TMV). Inside the rod, protein molecules are wound helically down the full length of the virus, housing & protecting the nucleic acid of RNA. The virus enters a host cell in a tobacco plant & commandeers its DNA, instructing it to code for TMV's own nucleic acids. The effect of TMV infection varies from outright death of the host plant or severe lesions resembling burn marks on the surface of the leaves to mottling of the leaves. Plant viruses like TMV are transmitted by insects, pests & nematode worms. Magnification: x34,000 at 6x4.5cm size.