The Virus
A virus is a genetic element containing either RNA or DNA. Viruses have two distinct states, extracellular and intracellular, the virus is only active in the latter state. Once inside a cell, the virus uses the cell's own manufacturing capabilities to reproduce itself.
An interesting property of viruses is their symetry. In fact, the degrees one must rotate a virus in order to see the same design is one way in which viruses are classified.
The Principal Types of Symetry in Viruses are:
Helical Symmetry: Usually found in Spherical and rod-shaped viruses. An example of such a virus is the tobacco mosaic virus.
Icosahedron: A spherical structure with 20 faces. Icosahedral symetry is the most efficient use of sub-units in a closed shell because it uses the smallest number of units to form a complete shell.(3 units per face for a total of 60 units per virus particle)
Try this activity...Cut out the design and fold along the lines.