Answer to Question #138695 in Biology for Hilma

Question

1. Viruses are generally considered to be non living. Should viroids and prions also be viewed as non living? Why [2]

2.A wart is caused by a virus that may lie dormant for years before symptoms appear. Does this resemble a lytic or lysogenic infection. Explain [2]

Answer 1

1) Viruses, prions and viroids are non-living organisms. This is because they require a living cellular host in order to reproduce. They cannot do it on their own. These parasites may be just a string of RNA, as in a viroid, or a length of DNA enclosed in a protein shell, as in a virus.

2) Resemble of wart is an example of lysogenic infection. Because lysogenic process is the following: the viral DNA combines with host DNA to form new set of genes, called prophage (provirus in eukaryotes). Whenever host cell divides, the prophage/provirus is copied along with host DNA and passed onto daughter cells. A trigger, like stress, can cause switch over to lytic cycle.