Are all viruses with RNA retroviruses?

Is polio virus a retrovirus?

Poliovirus, the causative agent of poliomyelitis (commonly known as polio), is a human enterovirus and member of the family of Picornaviridae. Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA genome that is about 7500 nucleotides long.

RNA virus. Viruses with RNA as their genetic material which also include DNA intermediates in their replication cycle are called retroviruses, and comprise Group VI of the Baltimore classification. Notable human retroviruses include HIV-1 and HIV-2, the cause of the disease AIDS.

They cannot synthesize proteins, because they lack ribosomes and must use the ribosomes of their host cells to translate viral messenger RNA into viral proteins. All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid.

The RNA polymerase does not need a fully uncoated nucleocapsid. Viral mRNAs are transcribed; these are capped, methylated and polyadenylated. Since this is a negative-strand RNA virus, RNA polymerase and RNA modification enzymes are packaged in the virion. The viral mRNAs are translated to give viral proteins.

There are four types of influenza viruses: A, B, C and D. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States. The emergence of a new and very different influenza A virus to infect people can cause an influenza pandemic.

Retroviruses(has RNA as genetic material) have genes for a very special enzyme called Reverse transcriptase, which has the ability to form double stranded cDNA from RNA. Enzyme production only begins when the virus infects a host cell and takes over the cell machinery and resources to transcribe its own genome.

Group VI: viruses possess single-stranded RNA viruses that replicate through a DNA intermediate. The retroviruses are included in this group, of which HIV is a member. Group VII: viruses possess double-stranded DNA genomes and replicate using reverse transcriptase. The hepatitis B virus can be found in this group.

HIV is classified as a retrovirus because it contains reverse transcriptase. It is a D-type virus in the Lentivirus family. Infection of cultured T4 cells with HIV usually results in cell death.

A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The virus thereafter replicates as part of the host cell’s DNA. Retroviruses are enveloped viruses that belong to the viral family Retroviridae.

Besides human immunodeficiency virus (HIV), the virus that causes AIDS, there a two other retroviruses that can cause human illness. One is called human T-lymphotropic virus type 1 (HTLV-1) and the other is called human T-lymphotropic virus type 2 (HTLV-II).

Twenty years ago Stephen Morse suggested that there were about one million viruses of vertebrates (he arrived at this calculation by assuming ~20 different viruses in each of the 50,000 vertebrates on the planet). The results of a new study suggest that at least 320,000 different viruses infect mammals.

However, retroviruses function differently, as their RNA is reverse-transcribed into DNA, which is integrated into the host cell’s genome (when it becomes a provirus), and then undergoes the usual transcription and translational processes to express the genes carried by the virus.

The Human Immunodeficiency Virus (HIV) is called a retrovirus because the RNA genome transcribes or copies back into the DNA in the host cell. This is by way of reverse transcriptase – a viral enzyme. HIV can only replicate itself within living cells. It uses cells’ replication enzymes to makes these copies of itself.

Retroviruses do not kill the host cell at first because they can insert their genome into the host genome. This process is called reverse transcription and is done by the viral protein reverse transcriptase. In the case of HIV, viral protein integrase then inserts the HIV DNA into host DNA.

When viruses cause an infection, they spread their DNA, affecting healthy cells’ genetic makeup and potentially causing them to turn into cancer. HPV infections, for instance, cause the virus’ DNA to combine with the host’s DNA, disrupting the normal function of cells.

Poliovirus, the causative agent of poliomyelitis (commonly known as polio), is a human enterovirus and member of the family of Picornaviridae. Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA genome that is about 7500 nucleotides long.

Retrovirus: A virus that is composed not of DNA but of RNA. Retroviruses have an enzyme, called reverse transcriptase, that gives them the unique property of transcribing their RNA into DNA after entering a cell. The retroviral DNA can then integrate into the chromosomal DNA of the host cell, to be expressed there.

retrovirus. A virus, such as HIV, whose RNA codes for DNA, which is then inserted into some part of the host’s DNA. This virus comes with its own special enzyme, called reverse transcriptase, which facilitates this insertion.

A retrovirus looks about the same as any other virus, but it functions significantly different that your run-of-the-mill influenza. HIV is the most significant retrovirus that infects humans; others include hepatitis B and human T-lymphotropic virus. Viruses are essentially just genes, encapsulated in a protein.

RNA viruses mutate faster than other DNA viruses because the enzyme RNA dependent RNA polymerase that synthesizes RNA does not have the activity of proof reading while DNA polymerase has this activity. Because of this absence of proof reading, wrong bases are inserted without correction and hence mutation is faster.

DNA Viruses: Dna virus is a virus that has DNA (deoxyribonucleic acid) as its genetic material. They are usually Large, Icosahedral, enveloped in Lipoproteins, Do not have polymerase enzymes, and cause Latent infection. Examples include Poxviruses, Herpesviruses, hepadnaviruses, Hepatitis b.