Viral Structure and Classification Overview

Overview of Viral Structure and Classification

• Viruses are mostly found in marine environments and infect amoebae.
• They can have DNA or RNA, single or double-stranded, and are enclosed in a protein coat, with some having a lipid envelope.
• Viral capsids can have icosahedral or helical structures, and some viruses have complex structures.
• Enveloped viruses include HIV and Influenza, while Poxviruses infect humans, Geminiviruses infect plants, and Bacteriophages infect bacteria.
• Envelope proteins are derived from the host cell's membrane, while attachment proteins are embedded in the outer layer of the virus.
• Viruses can be naked or enveloped, with genomes composed of DNA or RNA, varying in size and arrangement, and classified by ICTV and Baltimore classifications.
• Baltimore classification of animal viruses includes DNA and RNA viruses, with specific enzymes and tropism for host tissues.
• Human DNA viruses include Herpesviridae, Hepadnaviridae, Papillomaviridae, and Adenoviridae, while RNA viruses include Coronaviridae, Flaviviridae, and Picornaviridae.
• Viral replication occurs in a host cell, with the virus using the host's energy and machinery and the ability to produce mRNA.
• The viral replication cycle includes adsorption, penetration, uncoating, replication, assembly, maturation, and release from the cell.
• Replication processes vary for different types of viruses, such as DNA viruses replicating in the nucleus and RNA viruses replicating in the cytoplasm.
• Specific examples of viral replication processes include those of Adenoviridae, Herpesviridae, Coronaviridae, and Rhabdoviridae, among others.