Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.

Viruses are acellular infectious agents characterized by a simple structure and depend on host cells for reproduction. Structurally, a virus typically consists of:

– Capsid: A protein coat made of subunits called capsomeres, which encases and protects the genetic material. The capsid can have helical or polyhedral geometric forms.

– Genetic Material: Viruses contain either DNA or RNA as their genetic material, but never both. The type of genetic material varies:

– Plant-infecting viruses often have single-stranded RNA.

– Animal-infecting viruses may have single or double-stranded RNA, or double-stranded DNA.

– Bacteriophages (viruses infecting bacteria) typically have double-stranded DNA.

Viruses are considered obligate parasites because they cannot reproduce or carry out metabolic activities outside a host cell. They invade the host’s machinery, replicate, and then assemble and release new virions.

Four common viral diseases:

1. Mumps

2. Smallpox

3. Herpes

4. Influenza

These diseases are caused by different viruses with specific structures and genetic materials, emphasizing the diversity and pathogenic potential of viruses