Virus Capsid

This model shows a virus particle built from identical protein subunits tiled over an icosahedron, which has 20 faces, 12 vertices and 30 edges. Students pick a T number of 1, 4, 9 or 16 to retile the shell and watch the capsomer and subunit counts change. Sliders set the diameter and rotation, and toggles show spike proteins or a cutaway with the RNA genome inside. It is useful for talking about symmetry, why viruses reuse one small protein, and how structure relates to a tiny genome.

• Change the Capsid T number from T = 1 to T = 16 and watch Capsomers and Protein subunits grow.
• Drag Diameter between 20 and 120 nm and compare the readout with the size of a cell.
• Turn Spike proteins off and on to see where the spikes sit on the shell.
• Switch on Cutaway + RNA core to find the coiled genome inside the capsid.
• Count the 12 five-sided corners of the shell, then check them against the icosahedron facts.

1. 1Describe a virus as a protein shell enclosing a nucleic acid genome.
2. 2State the numbers of faces, vertices and edges of an icosahedron.
3. 3Explain how a larger T number means more protein subunits in the shell.
4. 4Explain why building a shell from many copies of one protein suits a small genome.

Questions teachers ask