Question

Figure 21.10 Which of the following statements is false?

a. In the lytic cycle, new phages are produced and released into the environment.

b. In the lysogenic cycle, phage DNA is incorporated into the host genome.

c. An environmental stressor can cause the phage to initiate the lysogenic cycle.

d. Cell lysis only occurs in the lytic cycle.

Short answer

Option : (c) An environmental stressor can cause the phage to initiate the lysogenic cycle.

Step-by-step solution

Introduction

Viruses do not multiply on their own; instead, they exploit the host cell's enzymatic machinery to do so, causing the host cell to malfunction. Virus reproduction refers to the generation of new viral particles within the host. The lytic cycle and the lysogenic cycle are the two processes by which viruses multiply and infect host cells.

Explanation to correct option

Option (c) The phage may begin the lysogenic cycle as a result of an environmental stressor. The lytic and lysogenic cycles are both possible for a temperate bacteriophage. Environmental factors such as hazardous chemical exposure or malnutrition may drive the phage to enter the lytic cycle, causing the host cell to die.

Explanation to incorrect options

In option (a), new phages are created and discharged into the environment during the lytic cycle. In the lytic cycle, the phage replicates within the host cell and produces additional phages, which are then liberated from the cell by bursting or lysis. As a result, it is an inaccurate response.

In option (b), the phage DNA is integrated into the host genome during the lysogenic cycle. The phage genome is reproduced in the lysogenic cycle once it has been integrated into the host genome. The viral genome is passed down through numerous generations in the lysogenic cycle as a result of this mechanism. As a result, it is an inaccurate response.

Option (d) indicates that cell lysis occurs solely during the lytic cycle. The lytic cycle begins after the lysogenic cycle is completed, in which the phase created in the host cell is released by bursting or lysis. As a result, it is an inaccurate response.

Conclusion

As a result, option (c) concerning bacteriophage replication is inaccurate. An environmental stressor can drive the phage to start the lysogenic cycle.