Which of the following characteristics, structures, or processes is common to both bacteria and viruses? a. metabolism b. ribosomes c. genetic material composed of nucleic acid d. cell division

Emerging viruses arise by a. mutation of existing viruses. b. the spread of existing viruses to new host species. c. the spread of existing viruses more widely within their host species. d. all of the above.

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.

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.

DRAW IT 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).