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2006-11-07 04:38:20 · 2 answers · asked by Sogol.A 1 in Science & Mathematics Biology

2 answers

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.

In the lytic cycle, characteristic of virulent phages such as the T4 phage, host cells will be induced by the virus to begin manufacturing the proteins necessary for virus reproduction. As well as proteins, the virus must also direct the replication of new genomes, the technique used for this varies greatly between virus species but depends heavily on the genome type. The final viral product is assembled spontaneously, though it may be aided by molecular chaperones. After the genome has been replicated and the new capsid assembled, the virus causes the cell to be broken open (lysed) to release the virus particles. Some viruses do not lyse the cell but instead exit the cell via the cell membrane in a process known as exocytosis, taking a small portion of the membrane with them as a viral envelope. As soon as the cell is destroyed the viruses have to find a new host.

2006-11-07 04:40:45 · answer #1 · answered by DanE 7 · 0 0

When a cell is affected by a virus, it combines it's DNA with host DNA and uses complete cell machinery for its replication and therefore results in the lysis of host cell.

2006-11-07 12:48:50 · answer #2 · answered by Sharada B 3 · 0 0

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