The outer surface of a virion consists of either a membranous envelope or a protein capsid. How does the outer surface correlate with a virus's mode of exiting a host cell?

To cause a human pandemic, the H5N1 avian flu virus would have to

a. Spread to primates such as chimpanzees.

b. Develop into a virus with a different host range.

c. Become capable of human-to-human transmission.

d. Become much more pathogenic.

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have

a. T2 protein and T4 DNA.

b. T4 protein and T2 DNA.

c. T2 protein and T2 DNA.

d. T4 protein and T4 DNA.

What features distinguish the seven major categories of viruses?

RNA viruses require their own supply of certain enzymes because

a. Host cells rapidly destroy the viruses.

b. Host cells lack enzymes that can replicate the viral genome.

c. These enzymes translate viral mRNA into proteins.

d. These enzymes penetrate host cell membranes.

Compare and contrast the bacteriophage lytic cycle and lysogeny by addressing

(1) the rate of replication of the viral genome

(2) production of virions, and

(3) effect on the host cell.

Redraw Figure 19.8 to show the replicative cycle of a virus with a single-stranded genome that can function as mRNA (a class IV virus).