Compact protein module that binds to a particular structural motif in another protein (or lipid) molecule, with which the signaling protein interacts:

When a virus infects a host cell, it uses the cell's machinery to make copies of its own genetic material in a process called replication. finally, during the process of self-assembly, that protein shell and the copies of the virus's genetic material are assembled into new viruses.

It is called the medulla oblongata or people usually call it medulla. it is the lower half of the brain stem continuous with the spinal cord.