Microbiology 5 - Replication of Viruses PDF

2/22/24, 12:37 AM Replication of Viruses Replication of Viruses Answers 1. Where is viral protein synthesized? e e e ¢ () () () () A. B. C. D. Endoplasmic Reticulum Nucleus Cytoplasm Mitochondria Answer: Cytoplasm (C) Viral protein is synthesized in the cytoplasm on polyribosomes. 2. Which stage of...

2/22/24, 12:37 AM Replication of Viruses Replication of Viruses Answers 1. Where is viral protein synthesized? e e e ¢ () () () () A. B. C. D. Endoplasmic Reticulum Nucleus Cytoplasm Mitochondria Answer: Cytoplasm (C) Viral protein is synthesized in the cytoplasm on polyribosomes. 2. Which stage of viral replication involves the virus particle becoming infectious? e (©) A. Maturation (J B. Budding C) C. Assembly () D. Release Answer: Maturation (A) Maturation is the stage of viral replication at which a virus particle becomes infectious. 3. Where is viral DNA usually replicated? e () C) C) () A. B. C. D. Cytoplasm Endoplasmic Reticulum Nucleus Mitochondria Answer: Nucleus (C) Viral DNA is usually replicated in the nucleus. 4. What is the stage where structural components come together for virus particle formation? e (©) A. Maturation (_) B. Release C) C. Budding e () D. Assembly Answer: Assembly (D) Assembly is the stage of replication during which all the structural components come together for virus particle formation. 5. Which process causes naked viruses to cause host cell lysis? https://quizgecko.com/quiz/441459/print/answers 1/10 2/22/24, 12:37 AM e e e e (A. () B. © C. () D. Replication of Viruses Acylation Glycosylation Disintegration Nucleic Acid Replication Answer: Disintegration (C) Disintegration (causing host cell lysis) is a part of the release process for naked viruses. 6. What is a Defective Virus characterized by? (J A. Deficiency in some aspects of replication e C) B. Rapid Replication () C. Complete Viral Structure C) D. Lack of Infectivity Answer: Deficiency in some aspects of replication (A) A Defective Virus is characterized by a deficiency in some aspects of replication. 7. What is the first step in the initiation phase of virus replication? e e e (©) A. Attachment () B. Uncoating (©) C. Maturation e (©) D. Penetration Answer: Attachment (A) During the initiation phase of virus replication, the first step is the attachment of the virus to specific receptors on the host cell. 8. How do enveloped viruses enter host cells? e e e () A. Injection ©) B. Budding () C. Endocytosis e () D. Fusion with the plasma membrane Answer: Fusion with the plasma membrane (D) Enveloped viruses enter host cells by fusing their envelope with the plasma membrane of the host cell to facilitate entry. 9. What is required for viruses to multiply? e e e e () © () () A. Dead cells B. Living cells C.Air D. Inorganic matter Answer: Living cells (B) https://quizgecko.com/quiz/441459/print/answers 2/10 2/22/24, 12:37 AM Replication of Viruses Viruses require living cells to multiply, as they lack the machinery for self-replication and depend on host cellular machinery. 10. What happens during the maturation phase of virus replication? e e e e () () () () A. B. C. D. Uncoating Attachment to host cells Fusion with plasma membrane Protein synthesis Answer: Protein synthesis (D) The maturation phase of virus replication involves protein synthesis within the host cell to produce new viral proteins. 11. Which type of viruses enter host cells by injection? e () A. Non-enveloped viruses e e e () B. DNA viruses () C. RNA viruses () D. Enveloped viruses Answer: Non-enveloped viruses (A) "Non-enveloped viruses" enter host cells by injection, a mechanism different from enveloped viruses. 12. What determines the susceptibility of a cell to a virus? C) C) (J) () A. B. C. D. Lipid components on the cell surface Presence of inorganic components "Uncoating" process of the virus "Endocytosis" mechanism of the cell Answer: Lipid components on the cell surface (A) "Lipid components on the cell surface" determine the susceptibility of a cell to a virus, as certain viruses recognize specific receptors on the cell's surface. 13. What is the mechanism used by some viruses to infect a cell by injecting only their genome into it? e () A. Translocating the entire virus into the cell e (J B. Entering the cell through endocytosis ()B. e e C) C. Fusing with the cell membrane () () D. Attaching to the cell surface and injecting its genome Answer: Attaching to the cell surface and injecting its genome (D) This mechanism is used by viruses that only require the gene for infection. 14. Which type of viruses are restricted to injecting only their genetic material into a host cell? e ¢ () A. Negative-sense, single-stranded RNA viruses () B. Double-stranded DNA viruses ¢ ()C. Retroviruses https://quizgecko.com/quiz/441459/print/answers 3/10 2/22/24, 12:37 AM e Replication of Viruses () D. Positive-sense, single-stranded RNA viruses Answer: Positive-sense, single-stranded RNA viruses (D) Positive-sense, single-stranded RNA viruses can be immediately translated upon entry. 15. What is the role of uncoating in the replication cycle of viruses? e () A. Separating the viral nucleic acid from the outer structural components e () B. Triggering cell lysis e e () C. Initiating viral replication () D. Enhancing viral attachment to host cells Answer: Separating the viral nucleic acid from the outer structural components (A) Uncoating allows the viral nucleic acid to function properly in the cell. 16. How is uncoating typically achieved during viral infection? e e e e () () () () A. B. C. D. By By By By passive diffusion through the escaping from lysosomes into direct fusion of the virus with cellular proteases opening up cell the the the membrane cytoplasm nuclear membrane capsid at low pH Answer: By cellular proteases opening up the capsid at low pH (D) Uncoating often requires the action of cellular proteases under specific conditions. 17. What must happen for successful expression and duplication of genetic information in viruses? e () A. Transcription of mRNAs from the viral nucleic acid e () B. Activation of host cell immune response e ()C. Translation of host cell proteins e () D. Replication of host cell DNA Answer: Transcription of mRNAs from the viral nucleic acid (A) Transcription of mRNAs from viral nucleic acid is essential for viral genetic expression. 18. Which stage of the viral replication cycle involves the time between uncoating and production of new infectious virions? e e e e () () () () A. B. C. D. Biosynthesis phase Eclipse phase Assembly phase Attachment phase Answer: Eclipse phase (B) The eclipse phase lasts until new infectious virions are produced. 19. During which phase of the viral life cycle does new virus particles assembly occur? e () A. Lytic phase https://quizgecko.com/quiz/441459/print/answers 4/10 2/22/24, 12:37 AM e e e Replication of Viruses ()B. Incubation phase ()C. Latent period () D. Synthetic phase Answer: Synthetic phase (D) The synthetic phase of the viral life cycle corresponds to the time when new virus particles are assembled. 20. At what time post-infection does the synthetic phase typically start? ¢ () A. 24 hours ¢ (|) B.6 hours « () C. 18 hours e () D. 12 hours Answer: 12 hours (D) The synthetic phase usually starts around 12 hours post-infection. 21. What distinguishes a latent viral infection from a chronic viral infection? e (A. Ability to lie dormant within a cell e e e () B. Production of new virus particles ceases () C. Viral genome is not eradicated () D. Production reaches a maximum plateau level Answer: Production of new virus particles ceases (B) A latent viral infection is distinguished by the fact that no extracellular infectious virus can be detected during the latent period. 22. Which part of the viral life cycle involves the ability of a virus to reactivate and produce large amounts of viral progeny without infecting the host with new outside virus? e e e e () A. Chronic phase () B.Lytic phase (JC. Synthetic phase () D. Latent period Answer: Lytic phase (B) This ability is associated with the lytic part of the viral life cycle, not the latent period or synthetic phase. 23. What happens to the viral genome during latency in certain viruses? e e () A. Becomes part of the host genome () B. Fully eradicated e () C. Continues to proliferate e () D. Remains dormant Answer: Remains dormant (D) During latency, the viral genome is not fully eradicated but remains dormant within the host. https://quizgecko.com/quiz/441459/print/answers 5/10 2/22/24, 12:37 AM Replication of Viruses 24. In which phase does extracellular virus become detectable after approximately 18 hours post-infection? e e e e () A. ()B. () C. () D. Incubation phase Latent period Synthetic phase Chronic phase Answer: Latent period (B) After ~18 hours post-infection, extracellular virus becomes detectable, marking the end of the latent period. 25. What is an abortive infection in virology? e e e e () () () () A. B. C. D. When a virus When a virus When a virus When a virus infects multiple cells simultaneously undergoes mutation to become more infectious infects a cell but cannot complete the full replication cycle infects a cell and successfully completes the replication cycle Answer: When a virus infects a cell but cannot complete the full replication cycle (C) Abortive infection occurs when a virus infects a cell but cannot complete the full replication cycle due to lacking some functional viral gene. 26. What is the role of interferons (IFNs) in response to pathogens? e e () A. Promote viral replication ()B. Inhibit viral replication e e () C. Enhance bacteria growth () D. Stimulate parasite development Answer: Inhibit viral replication (B) Interferons are signaling proteins made by host cells in response to pathogens like viruses, bacteria, parasites, and tumor cells. They inhibit the replication of viruses. 27. During which phase of the one-step growth curve does the input virus become uncoated? e e e e () A. ()B. () C. () D. Lysis phase Eclipse phase Adsorption phase Bursting phase Answer: Eclipse phase (B) The eclipse phase of the one-step growth curve corresponds to the period during which the input virus becomes uncoated, leading to no infectious virus being detected. 28. How can one virus interfere with the ability of a second virus to adsorb to the cell? C) A. By enhancing the second virus' attachment C) B. By promoting receptor production (J C. By increasing receptor availability (J D. By blocking or destroying receptors https://quizgecko.com/quiz/441459/print/answers 6/10 2/22/24, 12:37 AM Replication of Viruses Answer: By blocking or destroying receptors (D) One virus may inhibit the ability of a second virus to adsorb to the cell by blocking or destroying receptors. 29. What is the main cause of interference when two viruses infect the same host cell? e (J (J () (J A. B. C. D. One virus enhances the other's replication The host cell provides extra resources for both viruses Competition for components of the replication apparatus Interferons are released preventing both viruses' replication Answer: Competition for components of the replication apparatus (C) One cause of interference when two viruses infect the same host cell is competition for components of the replication apparatus. 30. Which statement accurately describes an inhibitory effect of one virus on another? () () C) (J A. B. C. D. Interferons prevent both The first virus enhances The first virus promotes The first virus competes viruses from entering host cells the second virus' adsorption to cells the second virus' replication for resources with the second virus Answer: The first virus competes for resources with the second virus (D) Inhibition between viruses can occur when one virus competes for resources with another, leading to an inhibitory effect on replication. 31. During the latent period of a viral infection, what can be detected after approximately 18 hours postinfection? C) A. Intracellular virus replication (J B. Host cell lysis C) C. Extracellular virus C) D. Viral genome eradication Answer: Extracellular virus (C) The latent period is when no extracellular infectious virus can be detected initially, but after ~18 hours, extracellular virus is detected. 32. What distinguishes a latent viral infection from a chronic viral infection? C) A. Presence of intracellular virus replication () B. Dormancy followed by reactivation C) C. Ability for the virus to lyse host cells () D. Rapid spread of the virus within the host Answer: Dormancy followed by reactivation (B) Latent viral infections involve dormancy with the potential for reactivation without active viral replication. 33. In which phase of the viral life cycle does the virus have the ability to lie dormant within a host cell? https://quizgecko.com/quiz/441459/print/answers 7/10 2/22/24, 12:37 AM e e e e (©) C) A. ()B. () B. () C) C. () D. Replication of Viruses Maturation phase Latent period Initiation phase Synthetic phase Answer: Latent period (B) Virus latency, where the virus lies dormant in a cell, is part of the latent period in the viral life cycle. 34. What happens during the synthetic phase of a viral infection? e (J A. Host cells undergo lysis () e C) B. Viral genome is eradicated C) C. Viral particles are inactivated () D. New virus particles are assembled Answer: New virus particles are assembled (D) The synthetic phase involves the assembly of new virus particles as part of the viral replication cycle. 35. What defines a latent viral infection? e e e () A. Continuous intracellular virus replication (J B. Potential for chronic symptoms in the host ()B. C) () C. Lack of interaction with host cells e () D. Dormant virus with ability to reactivate Answer: Dormant virus with ability to reactivate (D) A latent viral infection is characterized by a dormant virus that can reactivate to produce new viral progeny. 36. Which part of the viral life cycle involves the production of large amounts of viral progeny without infecting the host with new outside virus? e e e e () A. (J ()B. C) B. ()C. C) C. () D. Synthetic phase Initiation phase Latent period Maturation phase Answer: Synthetic phase (A) The synthetic phase allows for the production of viral progeny without infecting the host with new outside virus. 37. What distinguishes virus latency from clinical latency during the incubation period? e () A. Virus latency involves the ability to reactivate and produce new virus particles, while clinical latency is when a virus is not dormant. e C) ()B.B. Virus latency is the lytic phase, while clinical latency is the lysogenic phase. e ()C. (J C. Virus latency occurs during the synthetic phase, while clinical latency occurs during the latent period. e () (J D. Virus latency is when the viral genome is eradicated, while clinical latency is when the host gets infected with new outside virus. https://quizgecko.com/quiz/441459/print/answers 8/10 2/22/24, 12:37 AM Replication of Viruses Answer: Virus latency involves the ability to reactivate and produce new virus particles, while clinical latency is when a virus is not dormant. (A) In virus latency, the virus can reactivate and produce large amounts of viral progeny without infecting the host with new outside virus. Clinical latency, on the other hand, is when a virus is not dormant. 38. During which phase of the viral life cycle does the viral genome remain in the host cell without being eradicated? C) () C) (J A. B. C. D. Lysogenic phase Latent period Synthetic phase Lytic phase Answer: Latent period (B) During the latent period, the viral genome remains in the host cell without being fully eradicated, allowing for potential reactivation of the virus. 39. What characterizes a latent viral infection compared to a chronic viral infection? () A. Latent viral () B. Latent viral involve continuous C) C. Latent viral C) D. Latent viral infections infections host cell infections infections are short-term, while chronic infections are long-lasting. involve the proliferation of virus particles ceasing, while chronic infections infection. are always lysogenic, while chronic infections are always lytic. are always symptomatic, while chronic infections are asymptomatic. Answer: Latent viral infections involve the proliferation of virus particles ceasing, while chronic infections involve continuous host cell infection. (B) In latent viral infections, proliferation of virus particles ceases but can reactivate later. Chronic infections involve continuous infection of host cells. 40. Which phase of the viral replication cycle involves the production of large amounts of viral progeny without infecting the host with new outside virus? (J () CJ (J A. B. C. D. Lyric phase Synthetic phase Latent period Lysogenic phase Answer: Synthetic phase (B) The synthetic phase involves the production of large amounts of viral progeny without infecting the host with new outside virus during latent viral infections. 41. What happens to extracellular virus after approximately 18 hours post-infection? (J A. Extracellular virus is eradicated completely. C) B. Extracellular virus becomes undetectable. (J C. Extracellular virus starts to replicate rapidly. (J D. Extracellular virus is detected. Answer: Extracellular virus is detected. (D) https://quizgecko.com/quiz/441459/print/answers 9/10 2/22/24, 12:37 AM Replication of Viruses After ~18 hours post-infection, extracellular virus becomes detectable during the latent period of the viral infection cycle. https://quizgecko.com/quiz/441459/print/answers 10/10