why is it that virus replication is unique?

Answer 1

Viral populations do not grow through cell division, because they are acellular; instead, they use the machinery and metabolism of a host cell to produce multiple copies of themselves. They may have a lytic or a lysogenic cycle, with some viruses capable of carrying out both. A virus can still cause degenerative effects within a cell without causing its death; collectively these are termed cytopathic effects. Released virions can be passed between hosts through either direct contact, often via body fluids, or through a vector. In aqueous environments, viruses float free in the water.

Answer 2

2

Answer 3

Human immunodeficiency virus (HIV-1) will be discussed in detail here as an example of virus replication. In some cases, comparisons between HIV-1 replication and that of other viruses will be made, either because other viruses are better understood or to illustrate variations in these processes
The infectivity/particle ratio in picornaviruses can be as low as 0.1%, i.e. only 1 in 1000 virion particles are infectious. In rotaviruses, the ratio is about 0.2%. Virus particles may be defective for innumerable reasons. One consequence is that the study of replication is made more difficult. Information about the reproductive cycle of viruses comes largely from synchronously infected cells.
Shortly after infection and for several hours, only low amounts of parental infectious material can be identified, this is the so called eclipse phase. Genome replication has been initiated but progeny virus are not yet released. There is then a maturation phase when viral material accumulates exponentially in the cell or surrounding medium. After a few hours cells infected with lytic viruses become metabolically disordered and viral production ceases. Titres then slowly drop. Cells infected with non lytic viruses can continue to produce viral particles indefinitely. This reproductive cycle may vary from 6-8 hours in picornaviruses to more than 40 hours in some herpesviruses. Yields in cells infected with polio can be greater than 100,000 copies of virus per infected cell.
Viruses must enter an intact cell (host) and redirect the host biosynthetic processes for the synthesis of viral components

Viruses use host cells for replication

Host cells for each class of viruses are species specific and are often also tissue specific

Answer 4

I think what flounder meant to say was that some viruses contradict the "central dogma of molecular biology" (i.e. that DNA codes for mRNA which codes for protein). Retroviruses posses a unique enzyme called reverse transcriptase which allows them to made DNA copies from an RNA template.

Viruses lack most of the machinery required for their own replication and are reliant on cells to copy their genetic material an manufacture their proteins.

Answer 5

Boo to all the wikipedia cut and pasters. There are viruses besides phages and HIV you know.

Virus replication is unique because it doesn't follow the DNA to DNA rule imposed on all other forms of life. Viruses can replicate RNA to make RNA, can replicate DNA to make RNA to make DNA, can replicate RNA to make DNA to make RNA, and can replicate DNA to make DNA.

Viruses also replicate exponentially, meaning that a single template is the source for thousands of progeny. All other forms of life replicate linearly, one cell divides to make 2, 2 cells divide to make 4, etc...

Virus replication is also much more error prone.

Answer 6

Viruses are like dummies, they do not move. when it gets into your blood stream it sits on a cell and usually does nothing. Since a virus is surrounded by a layer of protein, your cell absorbs it in and then it reproduces the virus when the cell multipies.