What are viruses based on?

What are viruses based on?

Viruses are microscopic entities that have a core of genetic material, either DNA or RNA. The core is covered with a capsid, a protective coat made of protein. Around the capsid, there may be a spiky covering known as the envelope.

What is the most important factor for virus classification?

Because the viral genome carries the blueprint for producing new viruses, virologists consider it the most important characteristic for classification.

What are the different classes of viruses?

The seven classes of viruses in the Baltimore Classification System are as follows:

• 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 is the Baltimore classification scheme for viruses based on?

The Baltimore classification scheme groups viruses based on genome type and replication strategy. For a virus to replicate, it must generate mRNAs from its genome and there are seven ways of doing so, or seven classes of viruses.

How do viruses replicate?

Viruses cannot replicate on their own, but rather depend on their host cell’s protein synthesis pathways to reproduce. This typically occurs by the virus inserting its genetic material in host cells, co-opting the proteins to create viral replicates, until the cell bursts from the high volume of new viral particles.

Where do viruses fit in the classification system?

Classification of Viruses This is largely due to the nature of viruses, which are not living organisms by the classic definition, but neither are they necessarily non-living. Therefore, viruses do not fit neatly into the biological classification system of cellular organisms, as plants and animals do.

What criteria classify viruses?

The order of presentation of virus families and genera follows four criteria: (1) the nature of the viral nucleic acid; (2) the strandedness of the nucleic acid; (3) the use of a reverse transcription process (DNA or RNA); and (4) the positive or negative sense of gene coding on the encapsidated genome.

What are the two main parts of a virus?

The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.

Which four groups of viruses are considered RNA viruses?

1.1. RNA Viruses. Human diseases causing RNA viruses include Orthomyxoviruses, Hepatitis C Virus (HCV), Ebola disease, SARS, influenza, polio measles and retrovirus including adult Human T-cell lymphotropic virus type 1 (HTLV-1) and human immunodeficiency virus (HIV).

Which group or groups of viruses must package an RNA dependent RNA polymerase in the capsid of the virus along with the genome?

Group 5 negative ssRNA, MUST pack the viral polymerase protein.

What is the outer layer of a virus called?

Viral Morphology 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.

How are the different types of Viruses classified?

Classification based on the host range. Based on the type of host, there are four different types of viruses: These viruses infect by invading the cells of animals, including humans. Prominent examples of animal viruses include the influenza virus, mumps virus, rabies virus, poliovirus, Herpes virus, etc.

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 virus has DNA as its genetic material?

The virus, having DNA as its genetic material. There are two different types of DNA virus Single-stranded (ss) DNA virus: e.g. Picornaviruses, Parvovirus, etc. Double-stranded (ds) DNA virus: e.g. Adenovirus, Herpes virus, etc.

What do you call virus that infects bacteria?

The viruses that infect bacteria are called bacteriophages, or simply phages. The word phage comes from the Greek word for devour. Other viruses are just identified by their host group, such as animal or plant viruses. Once a cell is infected, the effects of the virus can vary depending on the type of virus.