A Virus as an Agent That Is Infectious - Assignment Example

Micro Essay Micro Essay Question One Answer A virus is an agent that is infectious and only has the ability to replicate in the living cells of other organisms. Viroids are plant pathogens that are usually not considered to be life form. Prions are composed of protein that is an infectious agent in a mis-folded form. In 1884, Louis Pasteur could not find out what was causing rabies and suspected the pathogen was too small. In 1898, it was discovered by Martinus Beijerinck that the agent that caused rabies multiplied into cells by dividing itself and the word virus was introduced. In early 20th century, a discovery was made of a group of viruses that infected bacteria. A breakthrough was made in 1931 whereby influenza was grown by Ernest William Goodpasture. In this year also it was made possible for one to view the virus using the electron microscopy an invention by Ernst Ruska and Max Knoll. The discovery of Prions began in 1960. In this year Tivkah Alper and John Stanley Griffith established their own hypothesis that some spongiform encephalopathies is transmissible and is caused only by agents that are infectious and that are protein in nature. Later on in 1970, Francis Crick recognized this hypothesis. In 1982, an announcement was made by Stanley B Prusiner the team had made a purification on a hypothetical infectious prion. This prion mainly entailed a specific protein. Pruisener later won a Nobel Prize in Medicine. Thus these are some of the breakthroughs that led to our understanding of viruses, viroids, and prions (Wagner, & Wagner, 2008). Question Two Answer Viruses have various shapes and sizes but are generally smaller than bacteria. Most viruses have a diameter of approximately between 20 and 300 nanometers. A virus consists of a protein protective coat that is called a capsid. A virus attaches itself to the host the penetrates the body of the host, after penetration uncoating takes place and therefore the viral genomic nucleic acid is released. Replication of the virus takes place and thus a person becomes sick. Prions are agents that are infectious and are composed only of protein called PrP27-30. This protein is made of 145 amino acids. Prion is transmitted from one person to another. It can also be transmitted if one eats meat that is contaminated. Replication then takes place in the body. Viroids are noncoding RNAs that are known to currently infect plants only. They happen to be smallest self-replicating units in the genetic system known to man. Viroids attack organisms by inhibition of the expression of specific genes. After several weeks or years depending on the type of plant, the growth becomes stunted (Dimmock, Easton, & Leppard, 2009, p.57). Question Three Answer Viruses are generally complex and are varied in composition. They are very small in size. All viruses have nucleic acid and protein. Viruses are either made of DNA or RNA. The nucleic acid found in the virus can either be made of one strand or it can be made of double strands. Replication of viruses occurs only in the host cells. Viruses use spikes to attach themselves to receptor sites that are found on host cells. Penetration for plant viruses is harder compared to animal viruses because plant cells have cell walls but animal cells don’t have cell walls. During the cycle of viruses, the first step of the virus life cycle is acquisition and infection. After the virus has penetrated the host, infection begins. Viremia is the phase that follows infection. This is a situation whereby the virus can be easily detected in the blood as the virus can be found in high concentrations. Early stages of replication start taking place in the viremia phase. Immune response is the phase that follows viremia. The high concentration of the virus alerts the immune system of the presence of a virus in this stage. Sterilizing immunity is the next phase. The immune system of the body fully reacts to destroy the virus in the body. In various cases of weak immunity the body is not capable of fighting off the virus. The last phase of the cycle is dissemination of new hosts. The virus exits the host in the hopes of finding a new host (Wagner, & Wagner, 2008). Question Four Answer Bacillus subtilis is a calatase positive bacterium that is found mostly in soil. It is rod shaped and usually has the special ability to survive tough conditions and tolerate extreme environmental conditions because it has a hard protective endosphere. Normally, when Bacillus subtilis is grown in fermented substances the growth of the cells increases and the enzymes are released at a much faster rate. In our case the enzyme are released at a rate that is too high because the solution is too highly concentrated and this caused the enzymes to be released at a very high rate. This will cause the cells to die thus causing the lysing of the fermenters. The increased release of the enzymes cannot keep up with the extra demand to keep the enzymes active thus causing them to eventually die, as they are no longer useful to the bacteria. Question Five Answer Protozoa are one celled animals also known as single celled animals. Protozoa have nuclei which is a characteristic that is common among animals and helps with mobility. They belong to Kingdom Protista. Most protozoa reproduce by asexual means of reproduction. Protozoa habitat is in moist places. However, some are parasites and live in animals and plants. Archezoa was a kingdom that was proposed for eukaryotes that were there before the existence of mitochondria. It is composed of Kingdom Parabasala and Kingdom Diplomadida. These two groups were believed to lack mitochondria. Microspora is a genus of algae that is found in taxonomy. It is specific of the Microsporaceae. Amoebozoa are a huge group of the amoeboid protozoa. They include the protozoa that move by making use of the cytoplasmic flow that is internal. They have pseudopodia that are blunt and appear to be finger-like. They are found mostly in soil and also in aquatic regions. Apicomplexa are a group of parasitic protists. Ciliophora are eukaryote and also belong to alveolata. Euglenozoa are large group protozoon that is flagellate (Hollar, 2012, p.68-76). Question Six Answer Lichen is an organism that mainly consists of a fungus and a photosynthetic partner. They grow together on the lichen in what is referred to as a symbiotic relationship. Some lichens appear to look like leaves and are referred to as foliosed lichens while others cover the whole trunk and branches of trees and are referred to as crustose lichens. Some lichen appears shrubby in nature and are referred to as fruticose lichen. Lichens are formed through a mutualism between some groups of algae and fungi to form what is called a lichen thallus. The green algae are what provide what we might call a home for the photosynthetic cells of the lichen. The green algae also help with absorption of water and nutrients that the lichen uses for its survival. Question Seven Answer Bergey’s Manual of systematic Bacteriology is a resource that was developed and that is mainly used to identify the species of bacteria. The system uses the aspect of characterization to be able to identify the different species of bacteria as they have different characteristics. It was first published by David Hendricks Bergey in the year 1923. The manual is basically just used to classify bacteria on the basis on their attributes; these are mainly structural and functional. Bacteria was mainly identified based on various phenotype including; the shapes and sizes, the motility of the bacteria, the spore production of the bacteria, the cell arrangement of the bacteria, the result of the gram strain of the bacteria, the optimum temperature at which the bacteria could grow in, the biochemical assays of the bacteria, the relationship to oxygen of the bacteria, among others. These were the main characteristics used in Bergey’s manuals to classify and identify bacteria (Priest, 1995). References Wagner, E. K., & Wagner, E. K. (2008). Basic virology. Malden, MA: Blackwell Pub. Page 298- 320. Dimmock, N., Easton, A., & Leppard, K. (2009). Introduction to Modern Virology. Chichester: John Wiley & Sons. Page 57-62 Hollar, S. (2012). A closer look at bacteria, algae, and protozoa. New York, NY: Britannica Educational Pub. Page 68-90. Priest, F., & Austin, B. (1995). Modern bacterial taxonomy. London : Chapman & Hall. Page 145. Read More