Lytic cycle

Lytic cycle

.

Description

The lytic cycle is a four-stage cycle.

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 RNA or DNA) into the cell. In doing, the cell is infected and can also be targeted by the immune system.

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 RNA.

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.

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. HIV, influenza and other viruses that infect eukaryotic organisms generally use this method.


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • lytic cycle — noun (biology) That part of the life cycle of a temperate phage in which it replicates uncontrollably, destroying its host and eventually releasing many copies into the medium (cf ↑lysogeny above) • • • Main Entry: ↑lysis …   Useful english dictionary

  • lytic cycle — lytic cycle. См. литический цикл. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • lytic cycle — (lit ik) A virus life cycle that results in the lysis of the host cell …   Dictionary of microbiology

  • lytic cycle — noun The normal process of viral reproduction involving penetration of the cell membrane, nucleic acid synthesis and lysis of the host cell See Also: lysogenic cycle …   Wiktionary

  • lytic cycle — The steps in viral production that lead to cell lysis …   Glossary of Biotechnology

  • lytic infection — The normal cycle of infection of a cell by a virus or bacteriophage, in which mature virus or phage particles are produced and the cell is then lysed …   Dictionary of molecular biology

  • lytic — A phase of the virus life cycle during which the virus replicates within the host cell, releasing a new generation of viruses when the infected cell undergoes lysis …   Glossary of Biotechnology

  • Lysogenic cycle — ) can release it, causing proliferation of new phages via the lytic cycle. Lysogenic cycles can also occur in eukaryotes, although the method of incorporation of DNA is not fully understood.Mixed cyclesFollowing are some types of viruses that… …   Wikipedia

  • lysogenic cycle — noun A form of viral reproduction involving the fusion of the nucleic acid of a bacteriophage with that of a host, followed by proliferation of the resulting prophage See Also: lytic cycle …   Wiktionary

  • литический вирус — lytic virus литический вирус. Вирус, размножение которого в клетке происходит по литическому циклу <lytic cycle> и приводит к ее лизису <lysis>. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А.,… …   Молекулярная биология и генетика. Толковый словарь.

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”