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Do viruses have DNA and RNA?

Do viruses have DNA and RNA?

Do viruses have DNA and RNA?

It is known that viruses are microscopic parasites, much smaller than bacteria, that have the capability to reproduce inside of a host body but not outside. But what is the basic structure of a virus?

Viruses and their structure

Viruses are small obligate intracellular parasites that cannot reproduce by themselves but when they infect a cell they make it produce more viruses. They contain the key elements that make up all living organisms, DNA or RNA, even though they lack the capacity to independently read and act upon the information contained within these nucleic acids.  The host’s cellular machinery allows viruses to produce RNA from their DNA (the transcription) and to build proteins based on the instructions encoded in their RNA (the translation). 

As said, for propagation viruses depend on specialized host cells. Those cells supply the metabolic and biosynthetic machinery of eukaryotic or prokaryotic cells. When a virus is completely assembled and capable of infection, it is known as a virion, whose function is to deliver its DNA or RNA genome into the host cell so that the genome can be transcribed and translated by the host cell. The viral genome is packaged inside a symmetric protein capsid. The nucleic acid-associated protein, called nucleoprotein, together with the genome, forms the nucleocapsid. In enveloped viruses, the nucleocapsid is surrounded by a lipid bilayer derived from the modified host cell membrane and studded with an outer layer of virus envelope glycoproteins.

Function of virus

As said, the primary role of the virus is to “deliver its DNA or RNA genome into the host cell.

First, viruses need to access the inside of a host’s body especially through. respiratory passages and open wounds that can act as gateways. Insects also can provide the mode of entry with their bites.

After that, viruses will then attach themselves to host cell surfaces. They do so by recognizing and binding to cell surface receptors and while viruses use them to their advantage, cell surface receptors are designed to serve the cell. 

Afterward, a virus can start to move across the outer covering or membrane of the host cell. There are many different modes of entry.
For example, HIV, a virus with an envelope, fuses with the membrane and is pushed through. The influenza virus, enveloped virus as well, is engulfed by the cell. Some non-enveloped viruses, such as the polio virus, create a porous channel of entry and burrow through the membrane.

Once inside, viruses release their genomes and also disrupt or hijack various parts of the cellular machinery. Viral genomes direct host cells to ultimately produce viral proteins (many a time halting the synthesis of any RNA and proteins that the host cell can use). Ultimately, viruses stack the deck in their favor, both inside the host cell and within the host itself by creating conditions that allow for them to spread.

Discoveries about viruses

The relationships between viruses need to be understood, beginning with noting similarities in size and shape, whether viruses contain DNA or RNA, and in which form. With new and more sophisticated methods of genome sequencing and comparing viral genomes, and with the constant discovery of new scientific data, information about viruses are more and more valuable. 

Sometimes it is not known how large viruses evolved but such discoveries bring up always new questions and open new avenues of research. In the future these studies may provide answers to fundamental questions about the origins of viruses, how they reached their present parasitic state, and whether viruses should be included in the tree of life.

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