Essay on Viruses

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.

The article first addresses the issue of whether or not to consider viruses as living. Although viruses used to be thought of as being biological chemicals due to the fact that they consist of nucleic acids

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, Plagues, and History, written by Michael Oldstone, is an insightful and highly educational book that details the history of, that’s right, viruses and plagues. Through typically dry, yet engaging prose, Oldstone recounts what seems like all of it while simultaneously bringing to light the contributions of those brave scientists who asked themselves, “why.” He focuses his attention on some of the most notable viruses such as smallpox, yellow fever, measles, polio, and later he focuses on more contemporary battles against disease.

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

Viruses - are extremely small particles made from protein and either DNA or RNA. They are not made up of cells instead they invade the living cells of other organisms and use them to produce many copies of

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.

Adenoviruses represent the largest non-enveloped or naked viruses at 75 nanometers and have 252 capsomeres that contribute to its icosahedral capsid structure (Doerfler 1996). The virus particle has spikes on the base of each capsomer that aid in attachment to the host cell. At the core of the virus is double-stranded linear DNA that replicates in the nucleus of the host cell.

The human herpes virus has a diameter of 150 nm. The DNA genome in the core is surrounded by an icosadeltahedral capsid. The capsid contains 162 capsomeres and it is enclosed with an envelope. Several glycoproteins are encoded into the envelope. Between the envelope and the capsid there is a space known as tegument which contains viral proteins and enzymes and it helps in replication

Retroviruses are a part of a large and diverse family of enveloped RNA viruses. They are defined by common taxonomic denominators that include composition, structure and replicative properties. “The virions are 80–100 nm in diameter, and their outer lipid envelope incorporates and displays the viral glycoprotein’s .The shape and location of the internal protein core are characteristic for various genera of the family. “ (Coffin, John M) The virion RNA is approximately 7–12 kb in size. It is linear, single-stranded, nonsegmented, and of positive polarity. A distinctive feature of this family is its replicative method which involves reverse transcription of the virion RNA into linear double

Polintons (also known as mavericks) are the large DNA transposons (9-22 kb long) that are widely distributed in eukaryotes [85–87]. Recently, it was shown that virophages (parasitic viruses of large DNA viruses) and Polintons, in addition to encoding several key homologous proteins including major and minor capsid proteins, FtsK-type packaging ATPase, protein-primed DNA polymerase B, retroviral-like family integrase and cysteine protease, exhibit similar genomic architecture (Figure A). These observations imply that Polintons and virophages are evolutionarily linked [61]. Although Polintons encode two capsid proteins, their ability to form virions has not been demonstrated.

I would use this poem to use with an introductory science lesson on viruses and how they spread. Lower elementary levels. First I would give students blue and red dot stickers. Two students would have red dots on their arms or hands, indicating they have a 'virus'. Students with the 'virus' will give red dots to two other students. Otherwise, students will give blue dots. By the end of the game, most students will have gotten the 'virus'. After the game, I would explain how viruses can be easily transmitted from one person to the other. As a follow up activity I would use the "You're it" poem to reinforce the objective of the lesson taught. Students will try to come up with some more lines to make the poem

The HIV-1 virion is approximately 120 nm in diameter, roughly spherical, and is composed of two copies of a single stranded positive sense RNA enclosed by a capsid (24). The HIV-1 genome is less than 10 kb and encodes for more than nine different gene products. It encodes for 3 major structural protein genes: gag (group-specific antigen), pol (DNA polymerase), and env (Envelope), which code for major structural proteins and essential enzymes. Gag generates the mature Gag protein matrix (MA or p17), capsid (CA or p24), nucleocapsid (NC or p7), and p6, which encompass proteins for the basic infrastructure of the virus such as the inner core of the viral particle (25). Pol encodes for reverse transcriptase (RT), which enables the virus to reproduce, integrase (IN), which is necessary to integrate the viral double stranded DNA into the host genome, RNAse H, and HIV protease, which are all encapsulated in the core of the inner particle formed by the viral capsid protein p24 (25). Env encodes for glycoproteins of the outer membrane such as outer gp120 (which enables the virus to attach and fuse to cells of the host), and transmembrane gp41 that anchors the glycoprotein complex to the surface of the virion (25). Between the core and the envelope is the HIV matrix proteins which are composed of the viral protein p17 (23). HIV-1 also encodes for proteins with important regulatory elements (tat (Trans-Activator of Transcription) and rev

Hanta virus is a dangerous and often deadly disease that must be guarded against. If proper precautions are not taken, hanta virus could lead to a nationwide outbreak causing many deaths. While there are a few cases of hanta virus reported each year, the consequences of coming down with the disease dictates that the U.S. set up certain safeguards to educate the population on how to protect themselves. Even though research is being done on hanta virus and its related illnesses, there persist many unanswered questions.