Viruses: Complex Molecules or Simple Life Forms? Viruses have been defined as "entities whose genomes are elements of nucleic acid that replicate inside living cells using the cellular synthetic machinery, and cause the synthesis of specialised elements that can transfer the genome to other cells." They are stationaryand are unable to grow. Because of all these factors, it is debatable whether viruses are the most complex of molecules or the simplest life forms. While the definition of living organisms must be adapted, the majority of evidence leads to the classification of viruses as living organisms. Viruses are composed of a nucleic acid core, a protein capsid, and occasionally a membraneous envelope. The nucleic acid core is composed of either DNA or in the case of retroviruses, RNA, but never both. In retroviruses, the RNA gets transcribed to DNA bye the enzyme reverse transcriptase. The protein capsid is a protein layer that wraps around the virus. There are four basic shapes of viruses. The tobacco mosiac, adenovirus, influenza virus, and t-even bacteriophage are each examples of a different virus structure. Each individual protein subunit composing the capsid is a capsomere. The tobacco mosiac virus has a helical capsoid and is rod shaped. The adenovirus is polyhedral and has a protein spike at each vertex. The influenza virus is made of a flexible, helecal capsid. It has an outer membranous enevelope that is covered with glycoprotein spikes. The T-even bacteriophage consists of a polyhedral head and a tail. The tail is used to inject DNA into a bacterium while the head stores the DNA. Basic life is defined as the simplest form capable of displaying the most essential attributes of a living thing. This makes the only real criterion for life the ability to replicate. Only systems containing nucleic acids are capable of this phenomenon. With this reasoning, a better definition is the unit element of a continuous lineage with an individual evolutionary history. Because of viruses inability to survive when not in a host, they must have evolved from other forms of life. The origin of viruses is an easy thing to theorize about so many hypothesese have been made. One such hypothesis is that viruses were once complete living parasites. Over time they have lost all other cellular components. This is backed up by the idea that all cells degenerate over time. Some people think along very similar lines that viruses are representatives of an early "nearly living" stage of life. This goes along with the first hypothesis in that it accounts for a loss of components. All creatures that become parasitic can be seen losing their obsolete functions and
contains three components. First it is constructed with a phosphorylated head group, then a three
Since therе are not any initial statеs of God that wе arе awarе of, and bеcause God doеs not act according to gеneral physic laws, thеre is no valid sciеntific еxplanation for how thе univеrse was creatеd. The diffеrent stеps of how diffеrent forms of spеcies dеveloped on Earth can bе еxplained by еvolutionary biologists, thеy can howеver not еxplain the purposе or valuе of evolution.
Every single living organism has deoxyribonucleic acid, but their cells vary. Some viruses use RNA though. The deoxyribonucleic acid, or DNA, found in organisms contain all the instructions necessary for creating different proteins that have different functions, but the molecule cannot leave the nucleus; this is where ribonucleic acid, or RNA, comes into play (Hall, 7). Deoxyribonucleic acid has multiple different components that come together in a structure that differs to the structure of ribonucleic acid (Hall, 9). Ribonucleic acid is very versatile with its build and functions. In the lives of DNA and RNA, each goes through processes known as replication, translation, meiosis and mitosis (Hall, 16, 18). During one of these processes, mutations can occur; one of these mutations can be the cause of oncogenic viruses (Hall, 53). RNA is an essential molecule that deals with coding, decoding, regulation and expression of genes (Epigenetics Modifications and Viral Infections, 2007-2014). When it comes down to epigenetic alterations in oncogenic viruses, it leads to the discovery of how viruses can infect our cells through inheritance such as some cancers. Deoxyribose and ribose are two nucleic acids that provide clues in the epigenetic alterations in early oncogenic viruses.
What are microorganisms? They are organisms that you have to view with a microscope. The three that I will be discussing are bacteria, viruses, and prions. Of the three, a bacterium is the only one that can be helpful to us in many situations, and they are also the most diverse organism on the earth. The structure, reproduction, and the diseases bacteria, viruses, and prion cause are all different. Let’s begin to compare these microorganisms.
Raymo uses for this is DNA and its ability to reproduce itself. This tiny double-helix
Species that now populate the Earth come from other species that existed in the past, through a process of descent with modification. Biological evolution is the historical process of transformation from one species in other descendant species, including the extinction of most of the species that have ever existed. One of the most romantic ideas in the evolution of life is that any two living organisms, different as they are, they share a common ancestor sometime in the past. We and any current chimpanzee share an ancestor of 5 million years. We also have a common ancestor with any bacteria that exist today, although time this predecessor to soar in this case more than 3000 million years. However, the idea of evolution by itself is an open concept, is a mechanical description of change does not say anything about the engine or the creative force behind the transformation. Thus, in principle, evolution can be driven by immanent laws of matter, or a divine creator or by blind forces,
There are two possibilities in relation to the origin of life: Either a supernatural being (God) created life or all life evolved on its own. Many people, who are known as
We are there food. Those germs of the past that best converted our bodies into their own propagation are the germs of the present. Those germs of the present that best convert our bodies into their own propagation will be the germs of the future. Why should we care about the prospects of one particular germ over another? Aren't they all just plain bad? The answer is no. We can never get rid of them all. Their future is our future. If their future goes one way, we will be relatively healthy; if it goes another, we will be sick or even dead. Neglect of the germ's-eye view of the world is not restricted to the average person; it extends to medicine as a whole for most of its history (Ewald 9). Scientists have proven that some viruses are to blame for certain diseases not the genes that have been inherited.
There are many virus’ and diseases known to mankind that have existed for many centuries. Some have cures whereas others sadly do not. Some may show symptoms and again others may not.
Even though AIDS is heavily researched, its origin still remains a partial mystery. It is know that HIV is a zoonosis, a human disease acquired from animals. The virus evolved from a Simian Immunodeficiency Virus (SIV): a type of slow virus found naturally in monkeys and apes which, while not harming the host, produces diseases in other primates (Caldwell 97).
How life came to be is a mystery that baffled the minds of even the smartest researchers. Although the researchers found no definite answers throughout the centuries, they had created many theories that could explain the origin of modern organisms. Evolution is a prominent theory among others, as supported by ancient ancestry, fossil evidence, and genetics. Evolution is the correct theory because the evidence, which is ancestry, fossil evidence, and genetics, proves evolution to have a solid argument.
them and how the virus itself adapts to meet the ever changing conditions of a
Masterson, K 2009, Where did swine flu come from? NPR, accessed 16 September 2015, .
First and foremost, a virus is defined as a particle composed of protein, nucleic acid, and sometimes, lipids, which can reproduce itself only by infecting live cells. The reason why viruses are questioned if they are living or nonliving is if they exhibit all the characteristics of life. One of the questionable characteristics regarding a virus is reproduction. Living organisms have the capability to reproduce on their own, sexually or assexually. However, viruses reproduce by infecting living cells, therefore being dependant on something. Another reason of why viruses are questioned as living or nonliving is their genetic code. Even though they have DNA and RNA inside a protein coat, they don't have a nucleus or ribosomes to copy their genes,
Viruses are important to discuss because they are analyzed in almost all microbiology classes. Viruses can be characterized as, “any of a group of submicroscopic entities consisting of a single nucleic acid chain surrounded by a protein coat and capable of replication only within the cells of living organisms” (Biology). Bacteriophage are more specific in a sense that they are “a virus that infects and replicates within a bacterium” not just any living organisms cells (Biology). These viruses can replicate in 2 different cycles: lytic cycle or the lysogenic cycle. If a virus takes enters the lytic cycle it will cause infection and destruction of the host cell. This is done when the virus first penetrates the cell membrane of the host cell.