Mirco Ch 5 & 9 viruses

13. How do prions cause disease? By corrupting mRNA expression in the cell By causing naturally occurring proteins in the cell to change shape By corrupting DNA replication in the cell By preventing translation from occurring in the cell By preventing proper RNA transcription termination

By causing naturally occurring proteins in the cell to change shape

6. How do bacteriophages invade bacterial cells? Endocytosis of the bacteriophage Via a hole in the cell membrane Through endocytosis of the bacteriophage By the bacteriophage directly injecting its nucleic acid By the bacteriophage fusing with the plasma membrane

By the bacteriophage directly injecting its nucleic acid

15. Enveloped viruses acquire their envelope from host cell membranes. True False

True

19. The second step in viral replication is entry. For bacteriophage, entry usually involves direct entry of the nucleic acid into the cell. receptor-mediated endocytosis. membrane fusion mechanism of entry. phagocytosis. digestion of the peptidoglycan.

direct entry of the nucleic acid into the cell.

31. A cell containing a prophage is called a virulent phage. provirus. prophage. temperate phage. lysogen.

lysogen.

29. HIV enters the cell through a/an _________ mechanism. receptor-mediated endocytotic membrane fusion acid-dependent endosomal phagocytic receptor-independent endocytotic

membrane fusion

11. Viroids are infectious RNA particles that cause infections in bacteria. plants and animals. bacteria and plants. animals. plants.

plants.

30. The quiescent phage genome, whether it exists as a plasmid or integrated into the host genome, is referred to as a virulent phage. provirus. temperate phage. prophage. lysogen.

prophage.

2. What is the viral capsid composed of? nucleic acid glycogen lipid polysaccharide protein

protein

22. Most non-enveloped animal viruses enter the host cell by pinocytosis. injection of nucleic acid into host cell. receptor mediated endocytosis. lysis of host cell membrane. membrane fusion.

receptor mediated endocytosis.

20. The influenza virus gains entry into a host cell by pinocytosis. lysis of the cell membrane. direct injection of its nucleic acid. receptor-mediated endocytosis. receptor-independent endocytosis.

receptor-mediated endocytosis.

25. The Baltimore classification scheme classifies viruses based on their mechanism of mRNA and genome synthesis. Using this classification scheme, all viruses are placed into one of ______ classes. five seven ten four three

seven

7. Which choice best explains the lack of enveloped viruses infecting plants and bacteria? lipid membranes from these organisms are not suited to endure environmental conditions plant and bacterial viruses produce capsomeres that are not compatible with envelope for-mation the plant viruses and bacteriophages have antigenic capsids the cell walls of plants and bacteria would prevent budding from occurring lipid membranes do not provide a way for the viruses to bind and penetrate cell walls

the cell walls of plants and bacteria would prevent budding from occurring

5. What is the most common way for enveloped viruses to enter animal cells? Through lysis of the cell Via a hole in the cell membrane Through endocytosis of the virion By the virion fusing with the plasma membrane By the virion directly injecting its nucleic acid

By the virion fusing with the plasma membrane

16. The zone of clearing as a result of a phage infection on a lawn of E. coli growing on the surface of an agar plate is called a/an.......

Plaque

1. Viral genomes may consist of which of these molecules? All of the choices are could be correct Single-stranded RNA Single-stranded DNA Double-stranded RNA Double-stranded DNA

All of the choices are could be correct

12. What is a prion? An infectious RNA particle An infectious DNA particle A type of virus A particle similar to a satellite virus An infectious protein particle

An infectious protein particle

28. Most enveloped viruses exit the host cell through cell lysis. True False

False

21. The influenza virus gains entry into a host cell by an endocytotic process. The viral nucleocapsid leaves the endosome and enters the cytoplasm through a membrane fusion mechanism. Fusion of the viral envelope with the endosomal membrane is facilitated by the production of proteases by the influenza virus. the production of a lipase by the influenza virus. sialic acid residues of the receptor proteins. specific viral protein recognition of pores in the endosome vesicle. a conformation change in the hemagglutinin to expose a fusion protein.

a conformation change in the hemagglutinin to expose a fusion protein.

8. What technique is usually used for the quantification of a bacteriophage suspension? a PCR assay a loop dilution assay a protein-based assay a direct count a plaque assay

a plaque assay

14. Gene therapy technologies may use viruses to cause disease and thus boost the immune system. to cause cytopathic effects in certain cells. as gene-carrying vectors for delivery to target cells. to stimulate cell destruction by the immune system. to destroy cells that are not functioning normally.

as gene-carrying vectors for delivery to target cells.

26. Most enveloped viruses exit the cell by Golgi transport. cytokinesis. cell lysis. exocytosis. budding.

budding.

3. What protective structure contains the viral nucleic acid? vacuole envelope nucleus endosome capsid

capsid

18. A non-enveloped virus will have its attachment proteins present in its envelope spikes, cytoplasm, capsid spikes, plasma membrane, cell wall spikes,

capsid spikes

27. Most non-enveloped viruses exit the cell by Golgi transport. cell lysis. budding. cytokinesis. exocytosis.

cell lysis.

24. The Baltimore classification scheme for viruses divides all viruses into seven groups based on their shape and presence or absence of an envelope. how they produce mRNA and replicate their genome. host and presence or absence of an envelope. their shape, host, and presence or absence of an envelope. Their shape and host.

how they produce mRNA and replicate their genome.

23. Plant viruses often gain entry into host cells by direct injection of nucleic acid into the host cell. membrane fusion mechanism. injury caused by insects to host cell. pinocytosis. receptor mediated endocytosis.

injury caused by insects to host cell.

17. Most likely, "host specificity" of a virus is determined by the presence or absence of an envelope. the type of nucleic acid it contains. viral nucleic acid replication strategies. interactions between viral attachment proteins and host cell receptors. viral enzymes.

interactions between viral attachment proteins and host cell receptors.

10. In Mad cow disease, prions act in which of the following ways? PrPC is converted to PrPSc. PrPSc is converted to PrPC . Native proteins denature and are later broken down to be recycled . Native proteins replicate excessively and cause cell lysis . Denatured proteins are refolded and then cause cell lysis .

PrPC is converted to PrPSc.

9. Which Domain contains the viruses? They are not classified at the domain level. Archaea Eukarya Bacteria It depends on their host.

They are not classified at the domain level.

4. What is the most common way for non-enveloped viruses to enter animal cells? Through lysis of the cell Via a hole in the cell membrane By the virion directly injecting its nucleic acid By the virion fusing with the plasma membrane Through endocytosis of the virion

Through endocytosis of the virion