Consider the separate stages of an animal virus life cycle. Assemble a list of structures and processes that are unique to the virus and would make good drug targets for an antiviral agent. Explain your rationale for each choice.

Explanation:

In order to make an antiviral agent, we need to find good drug targets, that is, to find structures and processes that are only present in the virus, so there is no harm on human cells when this antiviral agent is being applied.

In the virion of a naked virus, only nucleic acid and  protein are present forming the nucleocapsid. The nucleic acid and proteins of the capsid, specially, are found only in the virus and therefore make good drug targets. For example, we can express antibodies to recognize the proteins of the capsid and guide the immune system to destroy them.

Although virus particles are  metabolically inert, one or more key enzymes are present  within the virion in some viruses, for example, the reverse transcriptase. This enzyme is only found in viruses and if we find a way to inhibit the activity of this reverse transcriptase, like for example finding a competitor substrate, the virus will not be able to synthesize the DNA needed for its replication.

Regarding processes in the virus life cycle, they all have similar steps: first the attachment of the viral particle onto the cell, then the penetration of the virus, then the synthesis of early and intermediate enzymes using the host cell machinery, and finally the assembly of these viral components and lysis of the host cell to release new viral particles.

The attachment of a virion to a host cell is a highly  specific process. Recognition proteins on the virus recognize  specific receptors on the host cell. Substances that compete with the virion for these specific receptors can be used. If there is no attachment, there is no infection.