Lytic and lysogenic cycles Knowledge-Based Practice

Questions

1. 1.

   Which statement correctly describes the fate of the host bacterial cell upon completion of the lytic cycle compared to the lysogenic cycle?

   • A) The host cell undergoes lysis and dies in the lytic cycle, whereas it remains viable and continues to divide in the lysogenic cycle.
   • B) The host cell remains intact and continuously secretes virions in the lytic cycle, whereas it immediately ruptures in the lysogenic cycle.
   • C) The host cell forms a resistant endospore in the lytic cycle, whereas it undergoes metabolic dormancy in the lysogenic cycle.
   • D) The host cell fuses with adjacent bacteria in the lytic cycle, whereas its cellular membrane is degraded in the lysogenic cycle.
2. 2.

   During the lysogenic cycle of a bacteriophage, how is the viral genetic material replicated and propagated to new bacterial cells?

   • A) It is rapidly assembled into new virions that burst open the cell membrane.
   • B) It is copied synchronously with the host chromosome each time the bacterium divides.
   • C) It replicates independently in the cytoplasm as separate autonomous plasmids.
   • D) It utilizes reverse transcriptase to produce free-floating capsids within the host.
3. 3.

   During the bacteriophage lytic cycle, which step immediately follows the biosynthesis of viral nucleic acids and proteins?

   • A) Penetration of the viral genome across the host cell membrane
   • B) Assembly of newly synthesized viral components into complete virions
   • C) Integration of the viral genome into the host chromosome to form a prophage
   • D) Enzymatic lysis of the host peptidoglycan layer to release progeny phages
4. 4.

   Which event typically triggers a temperate bacteriophage to exit the lysogenic cycle and initiate the lytic cycle?

   • A) An accumulation of viral repressor proteins that stabilize integration
   • B) The rapid binary fission of the bacterial host under optimal conditions
   • C) Environmental stress, such as ultraviolet radiation, that causes host DNA damage
   • D) Complete degradation of the host cell wall by external lysozymes
5. 5.

   Which of the following processes occurs specifically during the lysogenic cycle of a temperate bacteriophage, but not during its lytic cycle?

   • A) Incorporation of the viral genome into the host chromosome to form a dormant prophage
   • B) Enzymatic rupture of the host cell membrane to release newly formed progeny virions
   • C) Rapid transcription of viral genes to assemble mature viral protein capsids
   • D) Degradation of the host cell chromosome immediately following viral genome entry

Answers and step-by-step solutions appear after you finish the test.