How are viral genomes classified?
With respect to the genome, viruses are broadly divided into DNA viruses and RNA viruses. Both DNA and RNA viruses can either single stranded or double stranded, with a circular, linear or segmented arrangement. DNA and RNA viruses are distinguished by their features, such as monopartite or multipartite.
What are the 6 genomic classes of viruses?
The Baltimore Classification System
- Class I: Double stranded DNA (dsDNA) viruses.
- Class II: Single stranded DNA (ssDNA) viruses.
- Class III: Double stranded RNA (dsRNA) viruses.
- Class IV: Single stranded RNA (ssRNA) viruses.
- Class V: Single stranded RNA (ssRNA) viruses.
What are the types of virus genomes?
The vast majority of viruses have RNA genomes. Plant viruses tend to have single-stranded RNA genomes and bacteriophages tend to have double-stranded DNA genomes. Viral genomes are circular, as in the polyomaviruses, or linear, as in the adenoviruses. The type of nucleic acid is irrelevant to the shape of the genome.
What classification is a virus?
Viruses are small obligate intracellular parasites, which by definition contain either a RNA or DNA genome surrounded by a protective, virus-coded protein coat. Viruses may be viewed as mobile genetic elements, most probably of cellular origin and characterized by a long co-evolution of virus and host.
Which virus has diploid genome?
Group VI viruses have diploid (two copies) ssRNA genomes that must be converted, using the enzyme reverse transcriptase, to dsDNA; the dsDNA is then transported to the nucleus of the host cell and inserted into the host genome.
Which of the following methods is used to classify viruses?
Viruses are classified by phenotypic characteristics, such as morphology, nucleic acid type, mode of replication, host organisms, and the type of disease they cause.
How many genome types are known?
Three different genomic types can exist derived from one SNP. Since we inherit each one genome from our parents, the combination of each pair of genome makes three different genome types. In the case of previous example of A-G mutation,three different genome types can exist – namely, AA, AG, and GG.
What is the basis of Baltimore classification system?
Baltimore classification is chiefly based on the transcription of the viral genome, and viruses within each group typically share the manners by which the mRNA synthesis occurs.
What is the composition of virion?
The virion, that is the complete infectious virus particle, includes a genome comprising one or a few molecules of either DNA or RNA, surrounded by a morphologically defined protein coat, the capsid; the capsid and the enclosed nucleic acid together constitute the nucleocapsid.
What are the three primary components of a virus?
A virion consists of a nucleic acid core, an outer protein coating or capsid, and sometimes an outer envelope made of protein and phospholipid membranes derived from the host cell. The capsid is made up of protein subunits called capsomeres. Viruses may also contain additional proteins, such as enzymes.
Which is the best classification system for viruses?
Classification of Viruses. Viruses can be classified primarily on their phenotypic characteristics, core content, chemical composition, capsid structure, size, shape, genome structure and modes of replication. The Baltimore classification is the most commonly used for studying the system of virus classification.
What kind of genetic material does a virus have?
Once it infects a susceptible cell, however, a virus can direct the cell machinery to produce more viruses. Most viruses have either RNA or DNA as their genetic material. The nucleic acid may be single- or double-stranded.
What is the structure and function of a virus?
Structure and Function Viruses are small obligate intracellular parasites, which by definition contain either a RNA or DNA genome surrounded by a protective, virus-coded protein coat. Viruses may be viewed as mobile genetic elements, most probably of cellular origin and characterized by a long co-evolution of virus and host. For
What kind of DNA does a class VII virus have?
Class VII viruses have a double-stranded DNA genome, but unlike Class I viruses, they replicate via a ssRNA intermediate. The dsDNA genome is gapped, and subsequently filled in to form a closed circle serving as a template for production of viral mRNA.
