The paper “ Biological Diversity - Viruses” is an outstanding variant of a literature review on biology. Tortora et al (2013) describe microorganisms as living organisms that are so small the human being cannot see them with the naked eye. A special device called a microscope, which magnifies the size of an image to beyond a hundred times its size, is required to view them. Microorganisms, also known as microbes, are responsible for many diseases that plague the human body. However, as Tortora et al (2013) explain, they offer very many benefits to human beings, even huge commercial value.
They include bacteria, fungi, protozoa, microscopic algae, and viruses. Tortora et al (2013, 27) define bacteria as a simple organism made up of a single cell that is not enclosed in any special nuclear membrane. The cell wall comprises of carbohydrates and proteins referred to as ‘ peptidoglycan’ . Bacteria also go by the name ‘ prokaryotes’ i.e. a ‘ pronucleus’ microorganism that can easily attach and fuse with another microorganism because of its light outer membrane. Bacteria have the capability of manufacturing their own food through photosynthesis and can consume inorganic material.
Again, Tortora et al (2013, 30) inform different bacteria that assume unique spherical, rod-like, spiral, star or square shape. Different species of bacteria from chains, pairs, spirals, clusters, and so on. A bacteria reproduce through binary fission that involves own subdivision into two equal cells. It acquires motion through moving appendages referred to as ‘ flagella’ . On the other hand, viruses are infectious organisms that are smaller than bacteria. Farabee (2007) describes viruses as sub-microorganisms made up of a nucleic acid core enclosed in a protein coat.
Unlike bacteria, viruses cannot perform metabolism, instead, they are parasitic to the cells that they infect. Tortora et al (2013, 396) explain that outside the host cell, the virus remains inert. Arguably then, the virus is not living microorganisms. However, viruses are intracellular parasites because one inside the host cell, viruses can reproduce, multiply, and even mutate. According to Tortora et al (2013, 396), a clinical view of viruses reveals them as ‘ alive’ because once inside the host cell, they multiply using the synthesizing machinery of the cell, and cause infection and disease.
Interestingly, viruses can synthesize the transfer of the viral nucleic acid to other cells, thus making them hosts of the viruses and causing them to become diseased. Some of the most salient differences between viruses and bacteria include; Bacteria can contain both deoxyribonucleic acid (DNA) and retro nucleic acid (RNA) while viruses contain only one. Bacteria reproduce through binary fission while viruses multiply inside the host cell. Bacteria are pronucleus as they have the plasma membrane while viruses have a protein coat. Bacteria can hardly pass through bacteriological filters while viruses can easily pass through because they are much smaller. Tortora et al (2013, 396) further explain that the identity of a virus lies in its simple structural organization and the mechanisms they employ in order to multiply.
A virus can have only one type of nucleic acid, either RNA or DNA but not both. According to Farabee (2007), two parts make up a virus. The outer part of a virus is a protein coat known as a ‘ capsid’ . However, on some occasions, carbohydrates, lipids, and more proteins may enclose this protein coat.
The inner part is the nucleic acid enclosed by the ‘ capsid’ . Besides the proteins, a viral particle also contains enzymes such as ‘ polymerases’ , whose function is to produce more viral RNA or DNA.