The lytic and lysogenic are the two main important terms of viral replication. They are an outstanding model of the life cycle of viruses.
They take on the host cell, and the virus maintains this host cell and also controls its cellular mechanism. There are differences between these two terms.
Let’s discuss them in this article.
- The lytic cycle involves a virus invading a host cell, replicating its genetic material, and causing the cell to burst. In contrast, the lysogenic cycle integrates the viral DNA into the host cell’s genome without causing immediate destruction.
- Lytic infections result in rapid viral replication and host cell death, while lysogenic infections can remain dormant for extended periods.
- Environmental factors or stress can trigger the lysogenic cycle to shift to the lytic cycle, causing sudden viral replication and host cell death.
Lytic vs Lysogenic Cycle
The lytic cycle is a viral life cycle in which the virus takes over the host cell’s machinery. The lysogenic process is a type of viral life cycle in which the virus integrates its genetic material into the host cell’s genome, producing new virus particles and cell lysis.
The lytic cycle executes over the host cell to produce its phage particles, eventually destroying all other cells. It starts with a virulent phage.
The T shape phage is the best illustration of how the phases of the lytic cycle perform their function. Lytic completes its process within four-six stages.
The lysogenic cycle has a proper continuous process; it has no stages. The phage penetrates the host cell through the penetration and attachment procedure.
Lambda phage is the best example for the explanation of the lysogenic cycle. The viral phage’s expression is genome but is not involved in the cycle process completely.
|Parameters of Comparison||Lytic Cycle||Lysogenic Cycle|
|Time Duration||Virulent bacteriophages show the cycle.||Cycle completed in a Long period.|
|The virulence||The cycle formed a prophage.||The cycle is virulent and shows fewer bacteriophages.|
|Lysis of bacteria cell||In this cycle, lysis occurs.||In this cycle, lysis does not occur.|
|Integration of viral DNA with DNA host||In this cycle, integration does not occur.||In this cycle, integration does not occur.|
|The formation of the Prophage||The cycle does not form prophages.||Many viruses form within the cell.|
|Virus formation within the cell||In this cycle, no virus forms within the cell.||In this cycle, no virus formed within the cell.|
What is Lytic Cycle?
It is one of the processes of viral reproduction which guide us to bacteriophage and bacterial viruses. This cycle results in the obliteration of the membrane and infected cells.
The bacteriophages of the lytic cycle are known as virulent phages. They are different from temperature phages.
The viral deoxyribonucleic acid or DNA exists separately in the bacterial cell as a free-floating molecule, and replicates are present there, separated from the aDNA host.
Another name of the lytic cycle is also a “reproductive cycle” of the bacteriophages.
Lytic completes its cycle in six stages: penetration, attachment, transcription, maturation, lysis, and biosynthesis. Let’s discuss them all one by one.
In the attachment cycle, the phage binds itself to the host cell’s shell just to inject DNA into the cell.
In the penetration cycle,, the process of injecting starts so the phage infiltrates DNA into the host by penetrating the cell membrane.
In the transcription, DNA is degraded via the host cell.
The metabolism of the cell is supervised to start phage biosynthesis. In this biosynthesis procedure, the DNA phage imitates internally in the cell and synthesizes new phage proteins and DNA.
What is Lysogenic Cycle?
The lysogenic cycle is a critical cycle of the reproduction of viruses.
It is also called Lysogeny, and it is represented by the integration of bacteriophage nucleic acid into the host bacterium genome or the appearance of a circular replicon in the cytoplasm of bacteria.
In this state, the bacterium reproduces and lives naturally.
The hereditary material of the bacteriophage is called a prophage and is transferred to daughter cells to each succeeding cellular division, and released. It releases through UV radiation or with certain chemicals.
The lysogenic cycle also occurs in eukaryotes. DNA phage first blends in bacterial chromosomes to produce more phage.
And in this cycle host, DNA is not hydrolyzed. DNA is replicated only, not released proteins. It does not result in instantaneous lysing of the host cell.
The transformation procedure in this host phenotype is known as phage conversion or lysogenic conversion.
In this, some less virulent bacteria are also present,, such as Clostridium botulinum, and Vibrio cholera.
The procedure involving a bacterium being infected by a temperate phage is called Lysogeny. It does not kill the host; the prophage genome integrates itself.
DNA replicated passes through new daughter cells during bacterial reproduction.
Main Differences Between Lytic Cycle and Lysogenic Cycle
- In the case of the lytic cycle cellular mechanism is entirely taken over by the viral genome whereas in the case of the lysogenic cycle cellular mechanism of the host is slightly distributed by the viral genome.
- The lytic cycle indicates the signs of viral replication; however, the lysogenic cycle does not indicate the signs of viral replication.
- The lytic cycle does not permit genetic recombination inside the host bacterium whereas the lysogenic cycle permits genetic recombination.
- The efficiency of viral DNA is increased in the lytic cycle whereas in lysogenic the Efficiency of DNA is reduced.
- The lytic cycle produces progeny of the virus whereas lysogenic does not yield viral progeny due to the fact that the viral particles are not liberated.
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.