Viral replication

Previous exams & Formative:

1- In the virus growth cycle; transmission of the virus particle or the nucleic acid from the surface of the infected cell to the interior of the cells is known as: a. Penetration b. Recognition c. Assembly d. None of the above

2- Un coating of virus particles occur in: a. Cell membrane b. Cytoplasm c. Nucleus d. All of the above

3- All of the following are true as regarding properties of virus particles except; a. They are obligate extracellular pathogens. b. Viruses have no metabolic activity. c. They depend on living host cells for providing energy and the synthetic machinery. d. Virus genome provides the host cell with genetic information needed for its replication

4- Release of progeny virus particles from host cell occur by: a. Cytolysis b. Budding c. Both a and b. d. None of the above

5- During release of RNA enveloped viruses from host cells, they acquire their envelope from: a. Nuclear membrane b. Cell wall c. Mitochondria d. Cytoplasmic membrane

6- Reverses transcriptase enzyme is: a. RNA dependent DNA polymerase. b. RNA dependent R NA polymerase. c. DNA dependent DNA polymerase. d. DNA dependent RNA polymerase.

7- The role of protease enzyme in the virus replication cycle is: a. Cleavage of precursor polypeptides into functional structural proteins. b. Facilitate uncoating c. mRNA transcription d. None of the above

8- Early synthesized viral proteins are: a. Envelope glycoproteins b. Enzymes required for replication of the viral genome. c. Structural proteins of the progeny virus d. All of the above.

9- Adsorption of virus particles to host cells characterized by all the following except: a. Virus and host cell are brought into contact by random collision. b. Attachment occurs if the host cell membrane contains specific receptors for the virus. c. The presence of receptors determines the cell tropism and viral d. Pathogenicity e. Fusion of viral envelope with cell membrane a. DNA viruses b. 'Emerging' viruses c. Influenza and HIV d. RNA viruses

10- Which viruses appear to be hypermutable?

11- Genetic variation in viruses contributes to their ability to evade the immune response. Select the principal means by which antigenic shift occurs in influenza A virus: a. Low fidelity of DNA dependent DNA polymerase. b. Low fidelity of RNA dependent RNA polymerase. c. Low fidelity of reverse transcriptase. d. Reassortment of fragments of the RNA genome. e. Recombination between RNA genomes

12- When Two viruses enter the same cell, replicate independently and produce their own characteristic type of infection, this is known as: a. Dual infection b. Recombination c. Reassortment d. Complementation

13- Mechanism of virus interference includes all of the following except: a. Blocking its receptors or by destroying its receptors. b. The cell enzymes necessary for viral growth are under the direction of the 1st virus. c. The 1st virus stimulates the infected cell to produce an inhibitor (interferon) that prevents the replication of the 2nd virus. d. Phenotypic mixing

14- Reassortment occurs in: a. Viruses with segmented genome. b. Defective viruses c. Host range mutants. d. Prions

15- Viral genome of one virus that may be encapsulated in the capsid of the second virus is called: a. Point mutation b. c.

EXTRA

1- The viral DNA replicate in: a. Cytoplasm b. Vacuole c. Nucleus d. Mitochondria

2- The protein coat of the virus remains outside the host cell: a. True b. False

3- Viruses require ______ for growth: a. Bacteria b. Plants c. Animals d. Living cells

4- The first step in infection of a host bacterial cells by a phage is: a. Adsorption b. Absorption c. Penetration d. Replication

5- In ........... Virus and host cell are brought into contact by random collision: a. Adsorption b. Penetration and uncoating c. Eclipse d. Assembly

6- In general, most DNA viruses multiply in the host cell's _, while most RNA viruses multiply in the host cell's: a. Nucleus, cytoplasm b. Cell membrane, cytoplasm c. Cytoplasm, nucleus d. Cytoplasm, cell membrane

7- In DNA viruses (except pox viruses) assembly occurs in: a. Nucleus b. Cytoplasm c. Mitochondria d. Extracellular

8- How do enveloped viruses exit their host: a. Rupturing the virus b. Bursting the host cell c. Budding or exocytosis d. None of these are correct

9- Transmission of the virus particle or the nucleic acid from the surface of the infected cell to the interior of the cells in: a. Adsorption b. Penetration and uncoating c. Eclipse d. Synthesis of new viral components

10- Attachment of the viruses to the cells: a. random b. should contain specific receptor

11- Viropexis occurs in: a. Enveloped viruses b. Non-enveloped viruses c. All viruses d. None of the above

12- Fusion occurs in: a. enveloped viruses b. Non-enveloped viruses c. All viruses d. None of the above

13- Uncoating of bacteriophage occurs in: a. Nucleus b. Cytoplasm c. Cell surface d. None

14- Uncoating of poliovirus occurs in: a. Nucleus b. Cytoplasm c. Cell surface d. None

15- Uncoating of herpes virus occurs in: a. Nucleus b. Cytoplasm c. Cell surface d. None

16- Synthesis of new viral components It includes synthesis of: a. Viral nucleic acid b. Proteins c. Both viral nucleic acid and proteins d. None of the above

17- In RNA viruses and pox viruses it occurs in: a. Nucleus b. Cytoplasm c. Mitochondria d. Extracellular

18- Release of Progeny Virions from the Cell by cytolysis in: a. Non-enveloped viruses b. enveloped RNA viruses c. enveloped DNA viruses d. none of the above a. Adsorption

19- The last step of Viral growth cycle is ......