Shapes Of A Virus

By: Chiara Longo

Shapes and sizes

Viruses come in an amazing variety of shapes and sizes. They are very small and are measured in nanometers, which is one-billionth of a meter. Viruses can range in the size between 20 to 750nm, which is 45,000 times smaller than the width of a human hair. The majority of viruses cannot be seen with a light microscope because the resolution of a light microscope is limited to about 200nm, so a scanning electron microscope is required to view most viruses.

Polyhedral

consist of nucleic acid surrounded by a polyhedral (many-sided) shell or capsid, usually in the form of an icosahedron.

Examples:

Transmission electron micrograph of Adenoviruses; courtesy of CDC.

Transmission electron micrograph of poliomyelitis viruses; courtesy of CDC.

Transmission electron micrograph of poliomyelitis viruses; courtesy of Dennis Kunkel's Microscopy.


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