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Encyclopedia > Lytic cycle

The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle. These cycles should not, however, be seen as separate, but rather as somewhat interchangeable. The lytic cycle is typically considered the main method of viral replication, since it results in the destruction of the infected cell. Image File history File links No higher resolution available. ... This article is about biological infectious particles. ... For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ... Lysogeny, or the lysogenic cycle, is one of two methods of viral reproduction (the lytic cycle is the other). ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the...

Contents

Description

The lytic cycle is a three-stage process.


Penetration

To infect a cell, a virus must first enter the cell through the plasma membrane and (if present) the cell wall. Viruses do so by either attaching to a receptor on the cell's surface or by simple mechanical force. The virus then releases its genetic material (either single- or double-stranded DNA or RNA) into the cell. In doing, the cell is infected and can also be targeted by the immune system. Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Left: An RNA strand, with its nitrogenous bases. ...


Biosynthesis

The virus' nucleic acid uses the host cell’s machinery to make large amounts of viral components. In the case of DNA viruses, the DNA transcribes itself into messenger RNA (mRNA) molecules that are then used to direct the cell's ribosomes. One of the first polypeptides to be translated is one that destroys the hosts' DNA. In retroviruses (which inject an RNA strand), a unique enzyme called reverse transcriptase transcribes the viral RNA into DNA, which is then transcribed again into mRNA. A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... The life cycle of an mRNA in a eukaryotic cell. ... Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A retrovirus is any virus belonging to the viral family Retroviridae. ... In biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzyme that transcribes single-stranded RNA into double-stranded DNA. Normal transcription involves the synthesis of RNA from DNA, hence reverse transcription is the reverse of this. ...


Maturation and lysis

After many copies of viral components are made, they are assembled into complete viruses. The phage then directs production of an enzyme that breaks down the bacteria cell wall and allows fluid to enter. The cell eventually becomes filled with viruses (typically 100-200) and liquid, and bursts, or lyses; thus giving the lytic cycle its name. The new viruses are then free to infect other cells. Plant cells separated by transparent cell walls. ... Viral lysis is the dissolution or destruction of cells by the action of a specific cytolysin. ...


Lytic cycle without lysis

Some viruses escape the host cell without bursting the cell membrane, but rather bud off from it by taking a portion of the membrane with them. Because it otherwise is characteristic of the lytic cycle in other steps, it still belongs to this category. Hepatitis C viruses presumably uses this method. This page is for the virus. ...


  Results from FactBites:
 
Mysterious Invaders - A Closer Look at Viruses (326 words)
Viruses that undergo the lytic cycle can be characterized as the viruses that are on a mission to "seek out and destroy" their host cell.
Penetration of the membrane occurs and the DNA is altered and the host cell actas as a viral manufacturing site until the cell eventually bursts to release the viral by-products into the body.
This cycle is slightly different from the lytic cycle in that the virus tends to become part of the cellular infrastructure instead of just destroying the host cell all together.
Lytic cycle - Encyclopedia, History, Geography and Biography (333 words)
The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle.
The lytic cycle is typically considered the main method of viral replication, since it results in the destruction of the infected cell.
In the lytic cycle, the virus invades the bacteria, and toxins are released, while in the lysogenic cycle, the virus invades the bacteria and takes over its DNA.
  More results at FactBites »


 

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