Question

Describe the difference between the lytic cycle and lysogeny when bacteriophage infection occurs.

Short answer

Answer: The main differences between the lytic cycle and lysogeny are: 1. In the lytic cycle, the phage replicates within the host cell, leading to cell lysis, and resulting in numerous progeny viruses. In lysogeny, the phage's genetic material integrates into the host's DNA without causing immediate harm to the host. 2. The phage in the lysogenic cycle can be induced to enter the lytic cycle, while the lytic cycle stays as it is.

Step-by-step solution

Define the Lytic Cycle and Lysogeny

The lytic cycle and lysogeny are two different outcomes of a bacteriophage infection. Bacteriophages, also known as phages, are viruses that infect bacteria. The lytic cycle is a process where a phage replicates within a bacterial cell and eventually lyses (breaks) the cell, releasing more phage progeny. Lysogeny, on the other hand, is a process where a phage's genetic material integrates into the bacterial host's DNA. Instead of destroying the host cell, the phage remains latent, allowing the host to continue to survive and reproduce.

Describe the Steps of the Lytic Cycle

The lytic cycle consists of the following steps: 1. Attachment: The phage attaches to the surface of the bacterial cell, recognizing specific receptors on the cell surface. 2. Entry: The phage injects its genetic material (either DNA or RNA) into the host cell. 3. Replication: The phage genetic material hijacks the host's cellular machinery to replicate its own genetic material and synthesize viral proteins. 4. Assembly: New virions (phage particles) are assembled using replicated genetic material and synthesized proteins. 5. Lysis and Release: The host cell is lysed, releasing numerous new phage particles that can infect other bacteria.

Describe the Steps of Lysogeny

Lysogeny consists of these main steps: 1. Attachment: Similar to the lytic cycle, the phage attaches to the surface of the bacterial cell. 2. Entry: The phage injects its genetic material into the host cell. 3. Integration: The phage's genetic material integrates into the host's DNA, resulting in a prophage - a combined genetic material of both host and phage. 4. Propagation: The host cell carries the prophage in its DNA and continues to replicate, passing on the integrated genetic material.

Identify Key Differences

The main differences between the lytic cycle and lysogeny are: 1. In the lytic cycle, the phage replicates within the host cell, leading to cell lysis, and resulting in numerous progeny viruses. In lysogeny, the phage's genetic material integrates into the host's DNA without causing immediate harm to the host. 2. The phage in the lysogenic cycle can be induced to enter the lytic cycle, while the lytic cycle stays as it is.

Provide Examples

Examples of bacteriophages that undergo the lytic cycle are the T4 phage and T7 phage, which infect Escherichia coli (E. coli) bacteria. An example of a lysogenic phage is the lambda phage, which can also infect E. coli; however, it can also integrate its DNA into the host genome, entering the lysogenic cycle.