van der Waals Bond: A weak noncovalent attraction due to a small, transient, asymmetric distribution of electrons around atoms.

Virions: Individual virus particles.

Voltage-Gated Ion Channel

A transmembrane channel found in excitable cells, such as neurons. A change in transmembrane electrical potential causes the channel to open, allowing ions to flow down their gradient. An action potential, for instance, is due to the activation of voltage-gated sodium channels.