subject
Biology, 14.11.2019 20:31 demij

This question is debated among scientists throughout the world. viewpoint #1 - man’s initial interest in viruses began with their association with disease. the word “virus” has its origins in the latin term for “poison.” in the late 19th century, scientific researchers discovered agents that behaved like bacteria causing diseases such as rabies and hoof-and-mouth, but were much smaller. like bacteria, viruses contain one of two nucleic acids: dna or rna it was apparent that these particles could be spread from one person to another, with serious consequences: illness and death. at this time it became the general view that viruses were biologically "alive," the simplest of all life on earth. an important characteristic of life is the response to stimuli. scientists noted that viruses may exist in two distinct states. when not in contact with a host cell, the virus remains entirely dormant. today, this is called the lysogenic cycle. during this time there are no biological activities occurring and the virus is nothing more than a static particle. viruses can remain in this non-living state for extended periods of time, waiting to come into contact with the appropriate host. when the virus comes into contact with the appropriate host, it becomes active, reacts to its environment and/or host and directs all its efforts toward self-replication. this cycle is referred to as the lytic cycle. the viral goal now is to produce more viruses that then attack more host cells. viewpoint #2 - in 1935 scientists discovered and crystalized the virus responsible for the tobacco mosaic virus. they further demonstrated that the particles lacked any mechanisms necessary for metabolic function. researchers were also able to determine, at this time, that viruses consisted of a nucleic acid, either dna or rna, surrounded by a protein shell. once again, the scientific view changed: viruses may be complex biochemical mechanisms but they are not alive. viruses apparently parasitize the biomolecular aspects of life. they depend on the host cell for the raw materials and energy necessary for nucleic acid and protein synthesis, as well as all other biochemical activities that allow the virus to multiply and spread. most simple life forms use cell division to reproduce, while viruses spontaneously assemble within cells. one might then conclude that even though these processes come under viral direction, viruses are simply nonliving parasites of other life forms. the simple question of whether or not viruses are alive, has defied a simple answer because it raises the fundamental issue: what defines life?

herpes simplex virus 1 (hsv-1), infects humans and produces most cold sores. the virus is contagious. herpes simplex can be spread through contact with saliva, such as sharing drinks. hsv-1 persists in the body by becoming latent and hiding from the immune system in the cell bodies of neurons. after the initial or primary infection, some infected people experience sporadic episodes of viral reactivation or outbreaks. how would scientists with viewpoint #1 respond to the description the herpes virus?
a) a virus is alive because it causes disease.
b) a virus is not living; it responds to chemical changes in the environment. c) a virus is alive; it can respond and/or adapt to changes in the environment. d) a virus is not living; it has no genetic material and does not undergo division.

ansver
Answers: 3

Another question on Biology

question
Biology, 21.06.2019 15:00
6. in the dna double helix, how are the two strands of dna held together? a. chemical bonds between base pairs hold the two strands of dna together. b. hydrogen bonds between the base pairs hold the two strands of dna together. c. hydrogen bonds between sugar groups and phosphate groups hold the two strands of dna together. d. chemical bonds between sugar groups and phosphate groups hold the two strands of dna together.
Answers: 1
question
Biology, 21.06.2019 16:00
15 points come and ! in which environment is someone least likely to find fungi growing? a around the sides of a hot tub b on a log in a tropical forest c beneath a mat in a shower d under a rock in the desert
Answers: 2
question
Biology, 22.06.2019 01:30
As a result of wildfires, in grasslands. a) tree growth increases b) grass growth increases c) soil quality decreases d) invertebrate variety decreases
Answers: 2
question
Biology, 22.06.2019 06:40
Under the soviet system, the government a. controlled all forms of communication. b. allowed newspapers to print whatever they wanted. c. controlled editorials but not the reporting of news. d. encouraged access to a wide variety of news sources. select the best answer from the choices provided a b c d
Answers: 1
You know the right answer?
This question is debated among scientists throughout the world. viewpoint #1 - man’s initial interes...
Questions
question
Social Studies, 13.12.2021 14:10
question
Social Studies, 13.12.2021 14:10
question
History, 13.12.2021 14:10
question
English, 13.12.2021 14:10
question
Physics, 13.12.2021 14:10
question
Business, 13.12.2021 14:20
Questions on the website: 13722362