Viruses, Bacteria, and Prions are all small organisms that can do incredible damage, but also help in other ways too. Each one has a different structural make up, and infects or helps humans in many different ways. In this paper ill talk about the structures of each, the reproductive methods, the ways that each infects humans or other organisms, and what other structures and organisms can be infected by each.
First off we will talk about the structural make up of each. Viruses each have a very specific structure, that doesn’t vary all to much from virus to virus. Each one has three main parts; The outer capsid, which is comprised of protein subunits encases the nucleic acid, and then there is a spike or spikes that protrude and are used for infecting hosts. Bacteria also have three main structural regions. Each on has appendages in the form of flagella or pili, and these are used for movement. Each also has a cell envelope consisting of a capsule, cell wall, and a plasma membrane. They also have the inner cytoplasm region which contains the DNA, Ribosomes and other organelles. Prions do not have a certain form that is known for sure, but their structure is caused by the folding of acids in the protein. Leading to a miss shaped protein unit that causes infection and spreads to other proteins. Prions, unlike viruses and bacteria, actually do not have nucleic acid, therefore cannot be treated the same way.
Each of these small structures, must like every other organism, reproduce. The only wa y to ensure the continuation of life, if that is what it can be called in these organisms, is to reproduce. Viruses reproduce by infecting specific host cells. The spike fits into only certain types of cells in a lock and key manner, which is...
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Guyer, Ruth Levy, Ph.D. “Prions: Puzzling Infectious Proteins” National Institutes of Health Office of Science. 28 July 2006 < science.education.nih.gov/nihHTML/ose/snapshots/multimedia/ritn/prions/prions1.html>.
In 1989, Fogleman et al. analyzed the uncoating and penetration of Simian virus (SV 40). It uses the ganglioside...
In the subsequent essay I will discuss and explain the relative function of the Prion protein. The Prion protein, also known as PrPC, ‘’is a membrane-anchored protein with two N-glycosylation sites and, although it is highly expressed in the nervous tissues, its physiological functions have yet to be well established’’ (Coordination Chemistry Reviews). PrPC/PrP is found in healthy brains in this form, and consists of 250 Amino Acids, yet after a simple misfolding in the secondary structure; this can alienate the PrP and forms PrPsc, which is the abnormal form of the Prion protein. The infectious agent PrPsc causes neuropathological changes in the brain, and instantly places the individual under the category of someone with the prion disease. PrPsc forms insoluble fibres and thus cannot be studied well using Nuclear Mass Resonance (NMR), and it is also more resistant to protease digestion. Furthermore, ‘’ The transmissible spongiform encephalopathies (TSEs) arise from conversion of the membrane-bound prion protein from PrPC to PrPSc, the latter being the scrapie form. Examples of the TSEs include mad cow disease, chronic wasting disease in deer and elk, scrapie in goats and sheep, and kuru and Creutzfeldt-Jakob disease in humans’’ (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904554/. 2014). The following diagram shows the conversion from PrPc to PrPsc:
Viruses have been long considered to be a living organism. They have their own DNA which makes it a debatable issue of whether or not to categorize them as living. They require energy to replicate/ survive within a host cell and so they take control of various organelles including mitochondria. [1]
PrP can occur in two forms- a normal cellular prion protein known as PrPc and a pathogenic misfolded conformer known as PrPsc. The abnormal PrPsc differs from the normal prion protein PrPc in both secondary and tertiary structure. PrPsc is principally rich in Beta sheet contents but PrPc is principally rich in alpha helical contents. Due to this difference of between the isoforms, prions are extremely resistant to certain decontamination systems. The Two tables below outline both human and animal diseases (2).
Scientists are stumped as to the development and nature of proteinaceous infectious particles. Neither virus nor bacteria, these prions, are believed to cause transmissible spongiform encephalopathies (TSE), rare diseases said to be 100% fatal, without possessing nucleic acids. Their unhindered growth is thought to be the cause for bovine spongiform encephalopathy (BSE), or Mad Cow Disease, Creutzfeldt-Jakob (CJD), scrapie and other TSE, diseases characterized by the brain microscopically turning into sponge-like matter. There are no cures or effective treatments available today because drawbacks constantly prevent the development of efficient therapy. Studies continue to slowly progress, hoping to find methods to immunize against more prion diseases.
In 1995, investigators Byron Caughey of the National Institute of Allergy and Infectious Diseases and Peter Lansbury of Brigham and Women’s Hospital found out an analogy of Vonnegut’s ice-nine and structure of prions. [2] The infectious particles that spreads the prion disease: scrapie consisted of highly stable crystals of a normally innocuous material found in the brains of sheep. [2] Crystalline clumps of this misfolded version of the protein coaxes other molecules of the same protein to fold into the aberrant conformation. The process continues until virtually all of that protein in a cell or tissue has been converted to prions. [2,3] Prion proteins have the capability to recruit other proteins of the same sequence as they grow into a neatly organized lattice structure. When a new monomer arrives, it links to the fibril and assumes the exact shape of its neighbor. Fibrils can ultimately cluster together to for...
Bacteria, viruses, and prions all have different types of structures. However, bacteria and viruses are more alike in the aspect of nucleic acid. Bacteria come in numerous shapes, but most bacteria are in the shape of a sphere (cocci). Their other shapes, or structure, are rods (bacilli), spirals (spirilla), and if they’re rigid then they are called spirochetes. Bacteria will normally come in a single cell form; however they can come in more than one, and they can also form chains. A bacterium doesn’t contain a nucleus because they are prokaryotes. On the other hand, it does have nucleic acid. The nucleic acid lies in the nucleoid plasmids. Bacterium doesn’t have membrane-bounded organelles and an outer cell wall. The outer cell wall is strengthened by peptidoglycan, which protects the bacteria from collapsing or bursting. Some bacteria have the means to move. The reason they’re able to move is because they have flagella. Flagellum is a long slender tail-like structure. Virus’s structure is less complex than the structure of bacterium. All viruses are composed of two parts: the outer capsid, and the inner core. The outer capsid is made of protein subunits, and the inner core contains the DNA. Also with virus structures comes the envelope. The envelope is part of the host’s plasma membrane...
A prion is a disease-carrying agent that is composed entirely of proteins. It is the cause of
Viruses are the simplest and tiniest of microbes, and are made up of proteins, nucleic acid, and lipids. The nucleic acids contain the genetic code that helps them grow and reproduce, but only once they find their way into a living organism. Viruses themselves are not considered living organisms because they don’t have cells, they don’t metabolize nutrients, produce and excrete wastes, and they can’t move around on their own. The remains of the nucleic acid then forms a covering, called the capsid. Once the capsid gets removed, viruses use the building materials of th...
Viruses have majority nonliving characteristics with little to none living characteristics. They do not have a cellular organization, metabolism,
Pathogens are organisms that are capable of causing diseases in other organisms and are considered to be ubiquitous. They can be found in water, on surfaces, and on or in humans, plants, and animals. Different pathogens have different signs and symptoms, treatment options, ways of transmission, diagnoses, and prognoses. Chickenpox, also known as varicella, and shingles are diseases caused by the same pathogen and have many of the same characteristics, but are also unique in their own ways.
My interest in the role of microbes and viruses began from UG classes (1993-1999) wherein professors taught us...
Part one of this essay will deal with defining bacteria, viruses, fungi, microbes, and pirons. Part two of the essay will focus on indigenous micro flora that is on and in the body, and part three will describe the structure and replication procedure of viruses.
This report provides an insight into the differences in the structure of cells and the way that they carry out their internal mechanisms. Cells form the basis of all living things and they are the smallest single unit of life. Cell biology is the study of cells and how they function, from the subcellular processes which keep them functioning, to the