Definition and Characteristics of Viruses

Definition and Characteristics of Viruses 1.2.1 Definition of Virus According to Experts Viruses have their own uniqueness if theyorarevirologists classifiedmhave as livingmthings. Based on this uniqueness, several researchers tried to carry out studies to define viruses. Here are several mscientists who have tried to define viruses . 1. Lwoff and Tournier (1966) Viruses only have oneacid). type Viruses of nucleicreplicate acid, namely DNA (deoxyribonucleic acid) or RNA (ribonucleic or multiply using this nucleic acid. However, viruses cannot grow or undergo binary fission. Viruses use ribosomes from their host cells to replicate or multiply. Therefore viruses are parasitic organisms. 2. Luria and Darnell (1968) Viruses asinunits whose genome is things nucleic(host acid,cells). namely DNAuseor aRNA, are produced the cells of other living Viruses complex system of hostmaterial cell synthesis that directly synthesizes viral genetic (viral genome) and transfers themviral intoparticles the cell. containing 3. Bawden (1964 Viruses are infective sub-microscopic units that replicate only intracellularly and are potentially pathogenic. 4. Hahon (1964) Hahon defines viruses as analogous tosaidtransmitters orofvehicles thatheredity carry genetic material information or can be to be pieces infectious that search forbechromosomes.Based on are several definitions of viruses fromof experts, it can concluded that viruses units that only have one type nucleic (DNAareorobligate RNA). Viruses only replicate within the cells of living creaturesacid so they parasiticcanorganisms. 1.2.2 Virus Characteristics Viruses are not likeprotozoa, unicellular microorganisms in general which include bacteria, parasites, fungi, mycoplasma etc. These microorganisms have cells and contain DNA system as genetic material andenergy also contain several types of RNA and have a complex for producing and macromolecular compounds. These microorganisms growacids,through the synthesis andof macromolecular compounds such as nucleic proteins, carbohydrates fats. These microorganisms reproduce by binary fission.such Viruses have unique characters. Viruses do not have functional organelles as mitochondria, golgi, chloroplasts andenergy, endoplasmic reticulum. Therefore, viruses depend on host cells to produce replicate or reproduce themselves and synthesize macromolecules. Viruses contain oneboth) type ofandnucleic acid, namely from DNA orother RNA (it is impossible to contain are different microorganisms.Viruses havecell, a lifeviruses cycle that is out divided into twoinertly phases.andWhen inbe the phase outside the host carry metabolism can considered as complex macromolecules. During the extracellular phase, viruses move depending on fluid and air movement and some of them follow the life cycle aofhigh the insect vector.thatThethepresence of these environmental factors can provide possibility virus can transmit or move to find a suitable host and have an influence on the spread or transmission of the disease itwhich causes. When inside the host cell, thegenome) virus carries outtheactive metabolism in the viral genetic material (viral exploits host cell' s complex system tocarbohydrates reproduce theandgenome, messenger RNA and viralareproteins (which include fats). After all the components formed, these components will become one unit to form a new virus particle called a virion. The virus replication process is presented in. Because viruses have uniquetocharacteristics, there ofarethethree theories thattheory have been put forward by experts estimate the origin virus. The first states that virusesbyoriginate fromcoat eukaryotic genesas inawhich nucleic acidexternal strands are protected a protein (capsid) defense from environmental influences. Theparasite secondthat theory states that the function. virus is inherited in the form of an intracellular loses its cellular Then, the third theory states that viruses independently originate from primitive molecules and develop independently through replication.