Viruses are microscopic parasites that are much smaller than bacteria. Viruses may seem like living organisms, but they are not. In order for viruses to reproduce, they need a host. A virus can not reproduce outside the host because it lacks certain qualities that the host cell has. Once the virus has successfully reproduced and can cause infections, it is called a virion. The genomes that viruses can have are single-stranded DNA, double-stranded DNA, double-stranded RNA, positive-sense single-stranded RNA, negative-sense single-stranded RNA, and DNA/RNA hybrid. The genetics that SARS-COV-2 specifically have are replicase, glycosylase, phosphorylase, and neuraminidase. The virus codes for four proteins. The four proteins are spike, membrane, envelope, and nucleocapsid. The spike (S) improves host cell entry and it is part of the outer structure of the virus. The membrane (M) is part of the outer structure of the virus. It helps keep the virus in their structure. The envelope (E) increases disease symptoms, it helps the new virus particles release and/or escape from the host cell, and it is part of the outer structure of the virus. The envelope comes from the infected cell, or host, in a process called “budding off.” The envelope plays a role in helping a virus survive and infect other hosts. The SARS-COV-2 virus is enveloped because it has already affected thousands of people in this world. When a virus enveloped it basically means that they are already between the host’s cells and are ready to reproduce and affect others. When the virus is a positive-sense RNA it allows immediate translation into the host cells. When the virus is a negative-sense RNA it needs to transform itself into a positive-sense RNA and then it can transfer into the host cells. A virus attaches to a specific receptor site on the host’s cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of the interactions between the host and virus depends on the host and the cells within the host. The virus will enter the host, leaving their capsid outside the cell. Once the virus enters the cell, the viral capsid is degraded and the viral nucleic acid is released, which then becomes available for replication and transcription. The replication mechanism depends on the viral genome. DNA viruses usually use the host cell proteins and enzymes to make additional DNA that is transcribed to messenger RNA, which is used to direct protein synthesis. RNA viruses usually use the RNA core as a template for synthesis of viral genomic RNA and mRNA. Viral replication is released and new virions are produced in the host’s organisms. With the new virus out called the Coronavius, it acts a bit differently. The coronavirus is also known as COVID-19. The virus attaches to the Angiotensin-converting enzyme 2 gene (ACE-2). The function of the ACE-2 is to regulate blood pressure. The ACE-2 is a negative regulator of the renin-angiotensin system and functions as the SARS-CoV-2 receptor and stabilizer of neutral amino acid transporter. ACE-2 is mainly expressed in vascular endothelial cells. ACE-2 is also expressed in the lung, kidney, and the gastrointestinal tract. The major substrate for ACE-2 is Angiotensin II. The virus affects the lungs, which are lined with epithelial cells. If the virus gets into your lungs then it comes into contact with the mucous membranes that line your nose, mouth, and eyes. The virus enters a healthy cell and replicates itself to make new virus cells and infect the newby cells. An article from Livescience, which they interview a researcher, from Westlake University, named Liang Tao and she stated “If we think of the human body as a house and 2019-nCoV [another name for SARS-CoV-2] as a robber, then ACE2 would be the doorknob of the house’s door. Once the S-protein grabs it, the virus can enter the house.” (Pappas, 2020). The virus enters the cell by endocytosis. Endocytosis is the process of actively transporting molecules into the body by engulfing with its membrane. After it is engulfed by the cell, it is transported to the endosomes and the virus envelope is broken down by acidic enzymes. This exposes the viral genome. The structural protein S can specifically bind to the receptor of the host cell. It is the key protein for viruses to invade susceptible cells. The M and E proteins are involved in the formation of the virus envelope, while the N protein is involved in the assembly of the virus. The genomic components of the coronavirus are divided into four different groups: alpha, beta, gamma, and delta. The one that humans and animals are infected with is beta. It is an enveloped, single-stranded, positive sense RNA virus. It consists of a 5′-terminal noncoding region, an S region encoding the spike glycoprotein (S protein). There is also an E region encoding the envelope protein (E protein). A M region encoding the membrane protein (M protein), and a N region encoding the nucleocapsid protein (N protein). There is a 3’-terminal noncoding region. Most viruses self assembly around the viral genome in the cytoplasm. There are two different ways a virus can get of the host cells. The first way is by killing the host cells. The second way is by pitching out of the host’s cell membrane and breaking away, which is also called budding, with a piece of the cell membrane. The reported symptoms for COVID-19 are dyspnea, shortness of breath, chest pain, fatigue, loss in taste and smell, headaches, dry cough, fever, rhinorrhea, and diarrhea. Sometimes there are no symptoms at all. All of these symptoms correspond to the coronavirus. The virus affects our organs. Our lungs, heart, kidney, and more. There is one symptom that does not correspond with the virus and that is the loss in taste and smell. It is a bit odd because the virus mainly attacks respiratory cells. I do think that symptom is legit because we breathe through our lungs, and if our lungs have been infected by the virus, then we may have difficulty inhaling and being able to smell. The symptom that is weird and does not correspond is the loss in taste. The virus affects our lungs and many other organs but not the way we taste. I do think the symptom is legit because many people who had the virus claimed that they lost their sense of taste.
References
Pappas, S., 2020. Scientists Figure Out How New Coronavirus Breaks Into Human Cells. [online] livescience.com. Available at: <https://www.livescience.com/how-coronavirus-infects-cells.html> [Accessed 28 April 2020].
Kuba, K., 2020. Multiple Functions Of Angiotensin-Converting Enzyme 2 And Its Relevance In Cardiovascular Diseases. – Pubmed – NCBI. [online] Ncbi.nlm.nih.gov. Available at: <https://www.ncbi.nlm.nih.gov/pubmed/23328447> [Accessed 28 April 2020].