Topic 2: Picornavirus case study After completing the Picornavirus case study of Topic 2 in the Virology segment, students should be able to: . describe the structure of the Poliovirus capsid and genome. • explain the replication cycle of Poliovirus including: - the host cell receptor used and the cell types expressing that receptor. - how the virus genome enters the host cell. - how the virus' (ti) RNA competes with the cellular mRNA for translation by the ribosomes, and how the virus eliminates the competition. - how the virus' replicates its genome using an RNA-dependent RNA polymerase. - describe how the virus progeny assemble and are released from the host cell. - describe the process of virus maturation that results in an infectious virus particle. . describe the different types of diseases caused by Poliovirus. • describe the two types of Poliovirus vaccine, and explain the advantages and disadvantages of each type, how they are administered and the type of immunity they confer to the host. See www.ubc.ca for information about UBC's snow policy. 1
iClicker Question For viruses with DNA genomes that replicate their genomes in the cytoplasm, which of the following statements would best describe how the viral polymerases work? A. The DNA polymerase would read the template 3' to 5', the RNA polymerase would read the template 3' to 5'. B. The DNA polymerase would read the template 3' to 5', the RNA polymerase would read the template 5' to 3'. C. The DNA polymerase would read the template 5' to 3', the RNA polymerase would read the template 3' to 5'. D. The DNA polymerase reads one strand of the template 3' to 5' and the other strand 5' to 3'. E. The DNA polymerase reads the template 3' to 5' and synthesizes RNA in the 3' to 5' direction. 2
iClicker Question Some viruses have a very narrow host range, meaning that they can only infect one or a small number of cell types, whereas others have broad host ranges, meaning that they can infect a large number of different cell types. What determines this? A. The number of virus receptors on the host cell. B. The number of anti-receptors on the virus particle. C. The number of cells that could potentially be infected by the virus. D. The virus particle has a structure that is complementary to a structure on the host cell. E. Whether the host can co-exist in the same environment as the virus. 3