Adenoviruses. Coloured transmission electron micrograph (TEM) of two adenovirus particles. Each virus is a characteristic 20-sided shape (an icosahedron) made up of a protein coat, or capsid, with a core of genetic material: double stranded DNA (deoxyribonucleic acid). The capsid of this virus is made up of 252 hexagonal and pentagonal subunits known as capsomers arranged to give the virus two-fold rotational symmetry. The adenovirus is most commonly associated with infections of the upper respiratory tract and eyes with symptoms resembling the common cold. However, in rare cases adenoviruses may be associated with cancer. Magnification: x250,000 at 6x7cm size. x850,000 at 8x10ins