Essay on virus

We hear how Henrietta’s cells helped learn and find cures about so many viruses, but what is a virus? A virus is a microscopic organism that only replicates within the cells of a host organism. One of the most well known viruses Henrietta’s cells helped us with was the polio virus. Polio virus is a viral infection of your central nervous system. Polio virus is a lytic virus meaning that, polio goes through reproduction and the cells bursts. Polio virus’s most extensive outbreak was in the early to mid-1990s. Thankfully the vaccine was released in 1995.

When we hear the word virus, we usually think of something that makes us sick. A virus is an ultramicroscopic infectious organism that, having no independent metabolic activity, can replicate only within a cell of another host organism. A virus consists of a core of nucleic acid, either RNA or DNA, surrounded by a coating of antigenic protein and sometimes a lipid layer surrounds it as well. The viral genome provides the genetic code for replication, and the host cell provides the necessary energy and raw materials. To fight viruses, we use vaccines. While some may infect a broad range, other viruses can only infect certain kinds of cells. Vaccines are made of inactive, dead or weakened virus cells or protein antigens that can no longer infect

The biological significance of this article is due in part to the fact that viruses are being considered as partway-living things. Even though they are only halfway living, per se, they are still an important part of the study of living things because of the unique way in which they “live” and continue to reproduce by taking advantage of host cells. The information in this article relates to biologists in that viruses provide an entirely different element of potential life, as they are a cause for reconsideration when it comes to defining and determining life and non-life forms. This

Viruses are microscopic particles that invade and take over both eukaryotic and prokaryotic cells. They consist of two structures, which are the nucleic acid and capsid. The nucleic acid contains all genetic material in the form of DNA or RNA, and is enclosed in the capsid, which is the protein coating that helps the virus attach to and penetrate the host cell. In some cases, certain viruses have a membrane surrounding the capsid, called an envelope. This structure allows viruses to become more stealthy and protected. There are two cycles in which a virus can go into: lytic and lysogenic. The lytic cycle consists of the virus attaching to a cell, injecting its DNA, and creating more viruses, which proceed to destroy the host. On the other hand, the lysogenic cycle includes the virus attaching to the cell, injecting its DNA, which combines with the cell’s DNA in order for it to become provirus. Then, the provirus DNA may eventually switch to the lytic cycle and destroy the host.

Viruses are coated genetic material that invade cells and use the cell's apparatus for reproduction.

A virus is a small capsule that contains DNA or RNA, viruses, unlike bacteria are not self sufficient and need a host in

Unlike bacteria, that have everything it needs to reproduce, viruses need to use a living cell's organelles in order to replicate.

The virus fuses with the cell’s plasma membrane. The capsid proteins are removed, releasing the viral proteins and RNA. Reverse transcriptase catalyzes the synthesis of a DNA strand complementary to the viral RNA. Reverse transcriptase catalyzes the synthesis of a second DNA strand complementary to the first. The double-stranded DNA is incorporated as a provirus into the cell’s DNA. Proviral genes are transcribed into RNA molecules, which serve as genomes for the next viral generation and as mRNAs for translation into viral proteins. The viral proteins include capsid proteins and reverse transcriptase (made in the cytosol) and envelope glycoproteins (made in the ER). Vesicles transport the glycoproteins from the ER to the cell’s plasma membrane. Capsids are assembled around viral genomes and reverse transcriptase molecules. New viruses bud off from the host cell.

A virus is a capsule containing genetic material, even smaller than bacteria. The main task of virus is to reproduce. However, viruses need a suitable host to

Some viruses also have an outer bag of lipo-protein called an envelope. After a virus attaches to a living cell, it either enters the cell to release the genetic information, or, the virus injects the information through the cells outer lining. Thus changing the cells natural functions and forcing the cell to spend its energy to create copies of the virus. The cell will go on making copies of the virus until the cell is used up and dies. The virus then leaves the dead cell and invades a nearby cell and the process starts all over. There are five types of human herpes virus: Varicella zoster which causes chickenpox, Epstein Barr virus which causes infectious mononucleosis, cytomegalovirus which can cause cytomegalic inclusion disease in infants, and herpes simplex viruses 1 and 2.

A virus is a noncellular particle containing a genome that can replicate only inside of a cell (Slonczewski and Foster, 2009). It contains an infective nucleic acid, virion, inside a capsid, which is a protective shell made up of proteins. Some virions have a method of transportation to transfer its genome into the host cell. Most often viral gene transfer mediates the evolution of cell genomes. When a virus infects the host cell, the genome of the virus subverts the host cell to make copies of the virus, which then escape to infect more cells (Slonczewski and Foster, 2009). The bacteriophages T4 and X174 were used because the sizes of them simulates a human pathogen, since a human viral pathogen cannot be used. Bacteriophage T4 is used to mimic a Human Immunodeficiency Virus (HIV) and bacteriophage X174 was used to mimic the Hepatitis C virus.

b) Fusion is another way viruses can enter the host cell, however only an enveloped virus can do so in this process. To enter the cell an enveloped virus has a structure known as the spikes, the spikes will than need to attach on the receptor cell to gain entry to the cell. capsid and chromosome are allowed entry in the cell and the spikes are left behind. 1111111

From the sequence scientists were able to determine that virus probably began its life in an animal then mutated before picking up the power to infect people.

The protective capsid helps the virus escape detection and destruction during the invasion of the host. When the virus reaches the target cell, biochemical reactions between the capsid and cell wall allow the virus to latch on and inject its genome into the cell’s interior. Once inside, the viral genetic material insinuates itself into the host’s DNA or RNA. In an efficient feat of natural bioengineering, the host cell’s genetic machinery now does the rest of the work for the virus. The cell, which had already been making copies of its own genome, now also replicates that of the virus. Coded within the viral material is the blueprint for making more copies of the viral genome. Further instructions command the production of capsids and directions for assembly of new viruses. After the host cell becomes engorged with viruses, it explodes, sending the new

Hanta virus like all other viri are some of the smallest organisms known to man. Their existence as living organisms is debated. Viri perform only the most basic functions of life. They seek