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Lytic Cycle of Virus

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  • Last Updated : 06 Sep, 2022
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The lytic cycle is named for the course of lysis, which happens when an infection has tainted a cell, reproduced new infection particles, and blasted through the cell film. This delivers the new virions, or infection edifices, so they can contaminate more cells.

Examples

  • T4 Bacteriophage
  • Ebola virus
  • Sars-Cov-2,etc.

Bacteriophage(virus)

Bacteriophage is also called phage or bacterial virus. The bacteriophage is discovered by the Frederick w. Twort in Great Britain(1915) and Felix d herelle in France (1917). A bacteriophage is a type of virus that infects bacteria. The word “bacteriophage” means “bacteria eaters”.

The bacteriophage destroys the host cells of the bacteria. The bacteriophage is composed of a nucleic acid molecule that is surrounded by a protein structure. A bacteriophage attaches itself to a bacteria and infects the host cell. The bacteriophage contains the head, tail, collar, Sheath, Baseplate, and Longtail fibers.

Phage

 

Life cycle of bacteriophage

After the infection, the phage attaches to the host cell of the bacteria. The phage usually follows one or two life cycles, lytic or lysogenic. Lytic phages take over the host of the cell to make the phage components. They destroy the cell by releasing new phage particles. Lysogenic phages inject their nucleic acid and replicate it without destroying the cell.

Another life cycle also exists like pseudolysogeny and chronic infection. Pseudolysogeny occurs when a host cell encounters unfavorable growth conditions and appears to play an important role in phage survival by enabling the preservation of the phage genome until host growth conditions have become advantageous again. In chronic infection, new phage particles are produced continuously over long periods of time but without apparent cell killing.

The page can replicate 2 different types of life cycles i.e. Lytic and Lysogenic cycles.

Lytic Cycle

The lytic cycle is also known as the vegetative life cycle when the phage ruptures the bacteria cell membrane. That page that only does the lytic cycle is known as virulent phage because they lead to the death of bacteria.

Steps 

Lytic Cycle

 

Step 1: Attachment

Attachment sites on the bacteriophage adsorb to receptor sites on the host bacterium. Most bacteriophages adsorb to the bacterial cell wall, although some are able to adsorb to flagella or pili. Specific strains of bacteriophages can only adsorb to specific strains of host bacteria. This is known as viral specificity.

Step 2: Penetration

On account of bacteriophages that adsorb to the bacterial cell wall, a bacteriophage protein “bores” an opening in the bacterial wall and the bacteriophage infuses its genome into the bacterial cytoplasm. A few bacteriophages achieve this by getting a sheath that drives an empty cylinder into the bacterium. This starts the overshadowing time frame. The genomes of bacteriophages that adsorb flagella or pili enter through these empty organelles. Regardless, just the phage genome enters the bacterium so there is no uncoating stage.

Step 3: Biosynthesis

Catalysts coded by the bacteriophage genome shut down the bacterium’s macromolecular (protein, RNA, DNA) union. The bacteriophage repeats its genome and utilization the bacterium’s metabolic hardware to incorporate bacteriophage proteins and bacteriophage primary parts.

Step 4: Assembly

After many duplicates of viral parts are made, they are collected into complete infections. On account of the T4 phage, proteins coded for by the phage DNA go about as catalysts for the development of the new phages. The whole host digestion is coordinated toward this get-together, bringing about a phone loaded up with new infections.

Step 5: Release

The lytic cycle looks like a little infection industrial facility. The pieces of the infection are all delivered freely, then collected, and lastly delivered into the climate.

FAQs on Lytic Cycle

Question 1: What is a lytic cycle?

Answer: 

When the infection has tainted the cell and reproduces the infection particles and blasts through the cell film.

Question 2: What is meant by Attachment?

Answer: 

Attachment sites on the bacteriophage adsorb to receptor sites on the host bacterium. Most bacteriophages adsorb to the bacterial cell wall, although some are able to adsorb to flagella or pili. Specific strains of bacteriophage can only adsorb to a specific strain of host bacteria. This is known as viral specificity.

Question 3: Who discovered the bacteriophage?

Answer: 

Bacteriophage was discovered by Frederick w. Twort in Great Britain(1915) and Felix d herelle in France (1917).

Question 4: What are the two life cycles of bacteriophage?

Answer: 

There is two life cycle lytic and Lysogenic cycle. Approx all bacteriophages choose either the first or second life cycle.

Question 5: What are the other life cycles except for the lytic and Lysogenic life cycles?

Answer: 

Pseudolysogeny and chronic infection are other life cycles.

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