DNA viruses have only the deoxyribonucleic acid (DNA) molecules as their nucleic acid; and the DNA can either be double-stranded or single-stranded as the case may be. The replication site of all DNA viruses is the nucleus of their host cell. Nevertheless, Poxviruses (which are also DNA viruses) replicate outside the nucleus of their host […]
Replication is defined as the process in which a cell divides to make copies of its genome or itself. Cell division or replication in viruses is different from what is obtainable in other microbes such as bacteria that mainly replicates by binary fission. Replication in viruses only occurs inside a suitable host, and in such
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Virology
As shown in Figure 1 above, a virion is composed mainly of three parts viz: the nucleic acid genome (DNA or RNA); the capsid or nucleocapsid; and the envelopes which surround the capsid or protein coat. The nucleic acid genome of a virus or virion can assume any of the following genetic composition: Viruses assume
MORPHOLOGY OF VIRUSES Read More »
Virology
Viruses are infectious agents that have a simple acellular structure that is mainly made up of a protein coat or capsid and a nucleic acid genome which can either be DNA or RNA. Some viruses also have envelopes (which are lipid-containing outer membranous layer that surround the nucleocapsid in some viruses) while others lack them,
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Virology
Several reasons exist for the inactivation of viruses I either to use them for a useful purpose such as in studying varying properties or to inactivate and attenuate their pathogenicity or virulence so that they do not cause harm to a living host including humans, animals and plants. Some of the major reasons for inactivating
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Virology
Viruses have several physicochemical properties including pH, molecular size or mass, stability to heat and susceptibility to organic solvents such as ether and other physical or chemical agents that may affect their proper development and replication. They react to various chemical and physical factors in their environment. These factors inclusive of chemical and physical factors
CHEMICAL AND PHYSICAL PROPERTIES OF VIRUSES Read More »
Virology
Viroids are sub-viral infectious entities that infect plants. They are acellular infectious agents like the prions that lack the essential features of a virus; and which are capable of directing their own replication since they have small naked RNA as their genome. Unlike the prions which lack nucleic acids (inclusive of DNA and RNA), viroids
Prions are sub-viral infectious entities that consist mainly of proteins. They are unique infectious particles that lack nucleic acids inclusive of DNA and RNA. Prions are infectious proteins that generally lack DNA and RNA; and they cause series of diseases in man and animals. They differ from the normal virion in so many ways. Prions
Fredrick Griffith showed in 1928 that deoxyribonucleic acid (DNA) is the genetic material of the cell. His work was unique because it was the first evidence that showed that DNA is the genetic material of the cell. Other scientists that also carried out experiments to establish that DNA is the genetic material include Oswald Avery,
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Biotechnology, Molecular Microbiology
An understanding of the nucleic acid molecules which include deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) important for us to understand the molecular and/or genetic basis of life. Nucleic acid molecules are found in all living organisms as the carriers of genetic materials from parent organisms to their offspring’s. With the exception of viruses (which
RIBONUCLEIC ACID (RNA) Read More »
Biotechnology, Molecular Microbiology