[Biology Class Notes] on Virology Pdf for Exam

In the field of microbiology, Virology primarily deals with the study of viruses as well as virus-like particles. The research and observations are based on the characteristics, classifications, and the relationship of the viruses with their hosts. Viruses are unique traits that set them apart from others in the microbiology world.

You know by now that viruses multiply fast and their structure is also quite different from other microscopic particles. Viruses are microscopic parasites that cannot thrive. They are capable of latching on to host cells and getting inside them. Here we will discuss virology meaning and the principles of virology.

 

What is Virology?

Virology came forward as a science at the end of the 19th century. It relates to the study of microscopic agents responsible for plant and animal infectious diseases. Tobacco mosaic virus, foot and mouth disease virus, and yellow fever virus were among the first viruses discovered. Approximately 30 years later (around the year 1927) there came forward a list of about three dozen diseases that were thought to be caused by viruses.

Viruses were mainly placed together according to their visual symptoms and modes of transmission. It was the first phase of Virology. Then came the electron microscope in the late 1930s. Viruses came to be known as particles. It did not take long to recognise these particles as nucleic acid and proteins. Thus, proteins and nucleic acids were firmly established as components of animal and plant viruses.

Over time, the introduction of cultured cells for in-vitro propagation of viruses accelerated the pace of virus discovery. There arose a need to classify and name groups of viruses. Biology, genetics, and morphology, and physicochemical properties of virus components came into the scene.  Around 2012, the introduction of extremely sensitive and high-sequencing technologies made dramatic changes. The world saw a multitude of novel viruses, most of them known by their genomic (hereditary) formation.

The classification of the virus according to their genome (hereditary) sequence may be in consideration as the ongoing phase of virus taxonomy or classification.

 

Characteristics of a Virus

As you know viruses are infectious agents with living and nonliving characteristics. A virus can infect animals, plants, and other microorganisms.  Viruses that infect only bacteria are known as bacteriophages.  Viruses that infect fungi are known as mycophages. And, the virus that attacks other viruses is known as virophages.  Characteristics of viruses can be living as well as non – living.

The Living Characteristics of Viruses are:

The Non – Living Characteristics of Viruses are: 

• They are not cells, contain no cytoplasm or cellular organelles. 

• They don’t grow and divide. 

• New viruses are synthesized and assembled within the infected host cell. 

• The majority of viruses possess either DNA or RNA, not both.

 

Types of Virus 

There are only two categories of viruses according to general composition- RNA and DNA.

RNA Virus – it is that type of virus that has RNA as its genetic material. It can be a single-stranded or double-stranded RNA. Diseases caused by the RNA virus include common cold, polio, hepatitis, influenza, measles, and SARS.  Plant virus is an example of an RNA virus.

DNA Virus – It is a type of virus that has DNA as its genetic material. They depend on the DNA and replicate using the DNA polymerase. They are sometimes double-stranded. In some cases, they can be single-stranded. Most of the animal viruses, bacteriophages, cyanophages, and animal viruses are examples of DNA viruses.

Based on genetic material, and type of host, we can say that there are three types of viruses – Animal virus, Plant virus, and Bacteriophages.

 

Molecular Virology

Molecular virology refers to the study of viruses at the molecular level. It involves the analysis of genes and gene products. It refers to the study of the interaction with the host- human, plant or animal- cellular proteins. Teams working in the lab think about molecular testing as the trend in the future. Molecular diagnostics have become the new normal. The introduction of automated systems provides the tools necessary to report accurate and sensitive results to clinicians – it can improve patient care and outcomes by correct and fast diagnosis.

 

Conclusion

The principles of virology state that a virus is made up of genetic material, known as either DNA or RNA. It is essential to understand that infections are of medical and veterinary significance. Virology has become one of the most important sub-disciplines of microbiology. It has allowed researchers to discover treatments and cures for the diseases that they cause.  Besides, virology is in use for pharmaceutical purposes also. Get the study materials from the website.