Anyone with a cold or the flu virus feels as if they are under attack by some organism. But in the scientific community it's still an open-ended question. This is why viruses do not belong to a kingdom of living things Just because a virus seems alive doesn't mean it is alive. After all, it's not even a single-celled organism
A virus is little more than a strand of DNA or RNA covered by a protein coating Viruses are a thousand times smaller than Abactena and come in a wide range of shapes. Some look like weird, tall spiders whereas others look like prickly porcupine-like soccer balls
One thing is for sure, viruses are very much a part of life on Earth and the human experience Viruses infect animals, plants, and even bactena. Humans are in a constant battle with viruses. HIV (the virus that causes AIDS), the Ebola virus, and the West Nile virus continue to make headlines and take millions of lives
Other maladies, such as colds, the flu, chicken pox, measles, and hepatitis, are more common, but sometimes just as deadly Symptoms vary depending on which kind of cell is under attack. Cold viruses attack the nose and throat, the rabies virus attacks the brain and nervous system, and the human immunodeficiency virus (HIV) attacks white blood cells in the bloodstream Viruses can even cause some kinds of cancers and leukemia
Live and Let Die
To determine whether a virus is alive or not, we could compare the virus's charactenstics to what many biologists consider the requirements of life. All living things have several common characteristics. Some nonliving things may have one or more of the characteristics but not all of them. For a virus then to be classified as alive it must :
Reproduce
Have Cells
Obtain and use energy
Grow, develop, and die
Respond to the environment and Maintain homeostasis
Evolve
Contain genetic material
Because viruses are not cells, they can't divide by binary fission like bacteria. Yet they do reproduce themselves in an extraordinary way Their structure enables viruses to attack a plant or animal cell called a HOST CELL The protein shell protecting the virus's DNA is covered with spike-like protrusions. These spikes allow the virus to latch onto the cells they infect. Once hooked on, the virus injects its genetic material into the host cell
The virus's DNA takes control of the cell once it's within the cytoplasm and begins to make the cell produce virus DNA and other parts of viruses. The host cell is forced to expend all of its energy and resources to help the virus replicate and make hundreds more viruses. The poor, weak cell usually bursts like an overinflated balloon from all the viruses and is destroyed in the process. Then, the replicated virus attaches itself to a new, unaffected host cell, and the viral infection continues
Living things do more than just reproduce. They also must obtain food to fuel the cell's metabolic activity. Some organisms, such as animals, eat other living things for energy. Other organisms, such as plants, harness the Sun's energy to make their own food. Because viruses aren't cells and have no activity within it, it has no need for food. However, the virus-controlled host cell needs material and energy to reproduce the viruses Maybe viruses can fit the requirement that life forms need to obtain and use energy
All other living things also grow or get bigger. A virus does nothing inside its protein coat, therefore it does not grow. But some scientists argue that a virus's growth occurs inside the host cell where parts of viruses are built dunng reproduction
Plants and animals react to the environment. All living things have ways of sensing the world around them and can respond to changes in their environment. Do viruses react? Viruses cannot move themselves, but there are some differences in opinion that viruses do react to changes in the environment
Remember, the virus's DNA or RNA can evolve over time, thereby increasing its chances for survival and adapting to the environment Like bacteria, they adapt through genetic mutations caused by rapid reproduction That is why it is so hard to cure viral diseases. Viruses keep changing their DNA and protein coat to further their "life form" and keep ahead of the game
What's Your Final Answer?
As humans, we like to classify things because it helps us understand the physical world Viruses must have a host cell to live and reproduce Outside of the host cell viruses are pieces of genetic molecules that can do nothing by themselves. Viruses are right on the border between living and nonliving Some biologists currently see the virus as a nonliving infectious particle Other bologists disagree and suggest they are alive because of what happens inside the host cell
Getting a definite answer if wuses are alive or not may never happen. But hey that's life.
Using this article:
1. Explain why some scientists believe that viruses are alive. Cite at least
3 examples from this article.
2. Explain why some scientists believe that viruses are not alive. Cite at least 3 examples from this article.
3. Do you believe viruses are alive or not? Explain your opinion in complete sentences.
1. Some scientists believe that viruses are alive because they exhibit certain characteristics that are typically associated with living organisms. For example, viruses reproduce by infecting host cells and using their resources to replicate. This is shown in the article when it states, "The poor, weak cell usually bursts like an overinflated balloon from all the viruses and is destroyed in the process." Additionally, viruses can evolve over time through genetic mutations, enhancing their chances for survival. The article states, "Like bacteria, they adapt through genetic mutations caused by rapid reproduction." Lastly, viruses can respond to changes in their environment, which is evident through their ability to adapt and keep ahead of the game.
2. On the other hand, some scientists believe that viruses are not alive because they lack essential characteristics of living organisms. Firstly, viruses do not have cells of their own, which is a fundamental requirement for life. The article states, "After all, it's not even a single-celled organism." Secondly, viruses do not obtain or use energy like other living things. While the virus-controlled host cell does require energy for reproduction, the virus itself does not have any metabolic activity or need for food. Lastly, viruses do not grow or develop on their own. They do not undergo any changes or increase in size within their protein coat.
3. In my opinion, I do not believe that viruses are alive. While they exhibit some characteristics of living organisms, such as reproduction and adaptation, they lack other essential traits like cells, energy metabolism, and growth. Viruses are highly dependent on host cells for their survival and reproduction, and outside of a host, they are essentially dormant genetic material. Therefore, they cannot be considered as fully alive entities.