information about viruses

 

VIRUS

Viruses are microscopic parasite that infects cells of biological organisms. A virus can only reproduce in living material by invading and utilizing living cells because the virus does not have the mobile equipment to reproduce itself. In the host cell, the virus is an obligate parasite and outside its host became helpless. Virus usually contain small amounts of nucleic acids were shrouded in a kind of protective material consisting of proteins, lipids, glycoproteins, or a combination of all three. Both virus genomes encode proteins that are used to contain genetic material and proteins required in the life cycle.The term usually refers to the virus particles that infect cells of eukaryotes (multicellular organisms and many types of single cell organisms), while the term used for a bacteriophage or phage types that attack cell types prokaryotes (bacteria and other organisms that are not nucleated cells) .Viruses often debated its status as a living because he can not run freely biological function. Because the typical characteristics of this virus is always associated with certain diseases, both in humans (eg, influenza virus and HIV), animals (eg bird flu virus), or plants (eg, tobacco mosaic virus)History of virusAccording to biologists, viruses are an intermediate organism between living things and inanimate objects. Transition because the virus is said to have the characteristics of living things, for example, has a DNA (deoxyribonucleic acid) and can multiply in living cells. Have characteristics such as inanimate objects do not have protoplasm and can be crystallized. The inventor of the virus such as D. Iwanoski (1892) in tobacco plants, followed by M. Beijerinck (1898), Loffern and Frooch (1897) find and separate the virus that causes foot and mouth disease (food and mouth diseases), Reed (1900) managed to find the virus that causes yellow (yellow fever), Twort and Herelle (1917) inventor of the bacteriophage, Wendell M. Stanley (1935) succeeded in crystallizing the tobacco mosaic virus. Knowledge about the virus continues to develop until birth branch of biological science that studies viruses called virology. 
1. Virus characteristics- Measuring ultra microscopic- Parasites true / obligate parasites- Shaped oval, round, rod, the letter Q, the coil- Capsid is composed of proteins that contain only DNA or RNA- Can be crystallized- The activities should in living cells 
 2. Structure and anatomy Virus
 To determine the general structure of the virus we use bacteriophage (virus T), the structure consists of:a. HeadHead virus contains DNA and enveloped capsid exterior. The units that make up the capsid protein called capsomeres.b. CapsidCapsid is a protein sheath. Capsid composed of capsomeres. Can also consist of a capsid protein monomers comprising the polypeptide chain. Capsid function to give shape to the virus as well as virus protection from adverse environmental conditions virus.c. Body contentAcid content section is composed of the nucleus, ie DNA alone or RNA alone. Content section called virions. DNA or RNA is the genetic material that contains the code of the nature of the virus. Based on the content it contains, the virus can be divided into viral DNA (T virus, smallpox virus) and RNA viruses (influenza virus, HIV, H5N1). In addition there is a virus on the contents of several enzymes.d. TailTail virus is a tool to attach to its host. Tail consists of TUBUS swear virus that has threads or fibers. Viruses that infect eukaryotic cells do not have tails.The smallest virus is only 20 nm in diameter (smaller than a ribosome), while even the largest viruses difficult to see with the light microscope.Viral genomic nucleic acid can be DNA or RNA. Virus genome can consist of double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA. In addition, viral nucleic acid genome can form a single linear or circular. Number of viral genes varied from four for the smallest up to several hundred for the largest. Most viral genetic material of animals and humans in the form of DNA, and in most plant viruses are single-stranded RNA.Viral genetic material enclosed by a protective layer. A protective protein layer is called the capsid. Depends on the type of virus, the capsid could round (spherical), helical, polyhedral, or more complex shape and consists of proteins encoded by the viral genome. The capsid is made up of many protein subunits called capsomeres. 
3. Reproduction VirusVirus reproduction known as proliferation consisting of:a. Lytic cycle (cycle litic)1. Adsorption phase (phase attachment)Characterized by the attachment of the virus tail in bacterial cells. Once the virus sticking lisoenzim secrete enzymes (enzyme destruction) to form a hole in the wall acid bacteria to enter the virus core.2. Phase Injection (insert acid core)Once the holes are formed in bacterial cells the virus will enter the core acid (DNA) into the bacterial cell body. So the viral capsid remains outside the bacterial cell and functioning again.3. Phase Synthesis (formation)DNA virus affects bacterial DNA to replicating virus parts, forming parts of the virus. In the bacterial cell helpless and synthesized viral proteins that serve as the viral capsid, in the control of viral DNA.4. Phase Asemblin (assembly)Parts of the virus that has been formed, by the bacteria will be assembled into the perfect virus. Number of viruses that formed about 100-200 pieces in a lytic cycle.5. Lytic phase (host cell breakdown)When assembly is completed, then the virus will destroy the cell walls of bacteria with enzymes lisoenzim, eventually the virus will look for a new host.b. Lysogenic cycle (cycle lisogenic)1. Phase MergerIn the insert DNA into bacterial DNA bacterial DNA viruses must decide, then inserts the viral DNA in the bacterial DNA thread is interrupted. In other words, in the bacterial DNA contained genetic material of the virus.2. Phase CleavageOnce the virus is inactive DNA inserts called prophage. Then replicating bacterial DNA to cleavage.3. Phase SynthesisTo synthesize viral DNA to form parts viirus4. Phase AssemblyAfter forming virus virus parts, and then entered into the DNA will form a new virus5. Phase Litik
 After assembly is complete bacterial cell lysis occurs. Viruses that regardless of the host will seek a new host 
4. Classification of VirusesAccording to the classification Bergey, viruses belong to the divisio Protophyta, class and order Virales Mikrotatobiotes (Virus). In 1976 the ICTV (International Committee on Taxonomy of Viruses) publishes that viruses are classified structure and composition of the body, which is based on acid content. Virus is basically divided into two groups, namely DNA viruses and RNA viruses.a. DNA viruses have several families:
    1. Family Parvoviridae like genus Parvovirus
    2. Family Papovaviridae like genus Aviadenovirus
    3. Family Adenoviridae like genus Mastadenovirus
    4. Herpesviridae family as the genus Herpesvirus
    5. Family Iridoviridae like genus Iridovirus
    6. Poxviridae family as the genus Orthopoxvirusb. RNA viruses have several families:
    1. Family Picornaviridae genus as Enterivirus
    2. Family Reoviridae such as genus Reovirus
    3. Family Togaviridae genus Alphavirus like
    4. Family Paramyvoviridae like genus pneumovirus
    5. Family Orthomyxoviridae like genus Influensavirus
    6. Retroviridae family as the genus Leukovirus
    7. Rhabdoviridae family as the genus Lyssavirus
    8. Arenaviridae like arenavirus family genus 
5. Role of Viruses in Human Lifea. Viruses are profitable, serves to:
    1. Making antitoxin
    2. Weaken bacteria
    3. Produce vaccines
    4. Invading pathogensb. Harmful viruses, diseases caused by viruses include:1. On vegetation
    On leaf tobacco mosaic virus Tobacco Mozaic
    Mosaic on potato Potato Mozaic Virus2. Tomato Tomato Aucuba mosaic on Mozaic Virus
    Phloem damage on citrus Citrus Vein Phloem Degeneration3. In Animals
    Newcastle disease in poultry New Castle Disease Virus
    Pox virus in cattle Vicinia
    Blue tongue in sheep Orbivirus
    Monkey monkey mammary gland tumors Mammary Tumor Virus4. In Humans
    Influenza Influenzavirus
    AIDS Retrovirus
    SARS Coronavirus
    Bird flu Avianvirus 
6. Self Defense Against Virus AttacksThe ability of viruses to cause disease is called virulence. Virulence of the virus is determined by:a. the presence and activity of the receptor on the host surface that allows the virus to attachb. the ability of the virus to infect cellsc. speed of viral replication in the host celld. the ability of host cells to resist viral attackMost of the virus enters the body through the mouth and nose, skin wounds. If there is a virus that goes, the body will maintain a cell by producing phagocytic cells, antibodies, and interferon (typical protein)