<P> The virion must assemble a stable , protective protein shell to protect the genome from lethal chemical and physical agents . These include forms of natural radiation , extremes of pH or temperature and proteolytic and nucleolytic enzymes . Delivery of the genome is also important by specific binding to external receptors of the host cell , transmission of specific signals that induce uncoating of the genome , and induction of fusion with host cell membranes . </P>
what is the function of a viral capsid
to protect the genome from lethal chemical and physical agents