Search results
Results from the WOW.Com Content Network
Structural model at atomic resolution of bacteriophage T4 [1] The structure of a typical myovirus bacteriophage Anatomy and infection cycle of bacteriophage T4.. A bacteriophage (/ b æ k ˈ t ɪər i oʊ f eɪ dʒ /), also known informally as a phage (/ ˈ f eɪ dʒ /), is a virus that infects and replicates within bacteria and archaea.
Prior to entry, a virus must attach to a host cell. Attachment is achieved when specific proteins on the viral capsid or viral envelope bind to specific proteins called receptor proteins on the cell membrane of the target cell. A virus must now enter the cell, which is covered by a phospholipid bilayer, a cell's natural barrier to the outside ...
Bacteria, like plants, have strong cell walls that a virus must breach to infect the cell. Given that bacterial cell walls are much thinner than plant cell walls due to their much smaller size, some viruses have evolved mechanisms that inject their genome into the bacterial cell across the cell wall, while the viral capsid remains outside.
Nonenveloped viruses lyse the host cell which is characterized by viral proteins attacking the peptidoglycan or membrane. The lysis of the bacteria occurs when the capsids inside the cell release the enzyme lysozyme which break down the cell wall. The released bacteriophages infect other cells, and the viral multiplication cycle is repeated ...
To infect a host cell, the virus must first inject its own nucleic acid into the cell through the plasma membrane and (if present) the cell wall. The virus does so by either attaching to a receptor on the cell's surface or by simple mechanical force. The binding is due to electrostatic interactions and is influenced by pH and the presence of ions.
A special hormone called interferon is produced by the body when viruses are present, and this stops the viruses from reproducing by killing the infected cells and their close neighbours. Inside cells, there are enzymes that destroy the RNA of viruses. This is called RNA interference. Some blood cells engulf and destroy other virus-infected ...
Numerous human pathogenic viruses in circulation are encased in lipid bilayers, and they infect their target cells by causing the viral envelope and cell membrane to fuse. Although there are effective vaccines against some of these viruses, there is no preventative or curative medicine for the majority of them.
Replication follows the ssDNA rolling circle model. DNA-templated transcription is the method of transcription. The virus exits the host cell by viral extrusion. [23] Viral assembly occurs at the inner membrane (in case of Gram-negative bacteria), mediated by a membrane-embedded motor protein complex. [23]