Is the Ebola Virus Eukaryotic or Prokaryotic, and is it a life form or non-life?

Answer 1

That's pretty sad Jowpers, you could at least weigh evidence before making broad proclamations. I hope you are a little more thoughtful with your students.

Ebola viruses are not eukaryotic or prokaryotic. Most virologists (including those with extensive knowledge of evolution) agree that viruses are alive. And virologists are the best qualified to say, wouldn't you think?

The primary argument against viruses being alive is that viruses are incapable of living outside of their host. Interestingly, this is true of many bacteria and some fungi as well.

There are 7 characteristics of life: homeostasis, organization, metabolism, growth, adaptation, response to stimuli, and reproduction.

Homeostasis - many bacteria don't maintain a stable internal environment, are they dead?

Organization - Viruses are organized, have you ever seen a crystal structure of a virion?

Metabolism - agreed, no

Growth - yes virus particles grow and mature in the host cell

adaptation (evolution) - very much yes

response to stimuli - Viruses respond to stimuli, just not the stimuli you think of naturally. Viruses modulate their reproduction and life cycles based on the "stimuli" in the host cell

Reproduction - Of course yes. Of course they reproduce and pass on their genes. And nearly all viruses encode their own replication proteins.

So the only characteristics that viruses fail to qualifiy as alive for are homeostasis and metabolism, and it could easily be argued that metabolism is the least important and most arbitrary characteristic of living organisms since viruses do a fine job of gathering energy from their environment (host cell). Some folks can't get over this arbitrary criteria so they refuse to give the idea any thought.

Answer 2

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Answer 3

The Ebola VIrus is a virus, not a cell, and only cells are classified as eukaryotic or prokaryotic. So the answer is 'neither'. Now, is it life? This question can be asked of ANY virus. Most scientists do not consider a virus to be truly alive (it needs cells to reproduce), but this is controversial.

Answer 4

All Viruses are non-living, all though they do show many characteristsics of living things and are considered an exception to Cell Theory. The terms Eukaryotic and Prokaryotic are used to describe organisms and a virus is not an organism, nor is it a cell.

Answer 5

There are theories on how life formed, one being from the comet which came loaded with animo-acids which are the basic building blocks of life. We know the basis for this is correct in that anino-acids do create proteins etc. but proving that's where it started is a bit harder without a time machine. Just the same as there's a theory from the creationist camp to say god created it all in 7 days. Not seen any evidence presented to back that one up either. Again we'd need a time machine to go backwards and see god doing it.

Answer 6

It's not a cell (so it's not prokaryotic or eukaryotic), and it's NOT alive. Viruses fail to fulfill most of the characteristics which define life. For example: they are unable to reproduce on their own, and their metabolism is extremely limited (i.e. they do not harvest their own energy or generate waste products).

Very few biologists consider viruses to be alive. However, medical researchers sometimes refer to them as living (but then again most medical people are not interested in such questions... their interest in and understanding of systematics is equally lacking).


In response to "floundering penguins" below:

Yes, I can see how the way I worded my response may seem a bit harsh. Despite that, I'm a little baffled by your attack. My point was that you classify things based on what's important to you. Medical researchers often classify pathogens based on the symptoms they cause. That's certainly not unreasonable as this system is more useful for them. As you might expect, medical texbooks generally ignore phylogeny when discussing viruses and protists. I don't know of any biology textbooks that consider viruses to be alive and I'd be very interested in seeing the evolutionary virology research you mentioned. Viruses certainly do evolve, but there is much more to life than that. The attributes you have discussed also apply to self-replicating molecules (such as ribozymes and transposons) which are certainly not considered to be alive. As you yourself have pointed out, viruses cannot perform these functions autonomously. Viruses are not considered to be simple life, but rather they are considered to be highly evolved transposons (i.e. they are an offshoot of living systems). By your definition the genome itself is alive (and reproducing within the environment of a cell).

Despite what you have inferred, I'm a molecular biologist and I do have quite a bit of knowledge in this area. My stance in class is that viruses are "almost alive" and I spend quite a bit of time discussing this grey area with my students. However, based on well established critera, they are clearly NOT alive (A line has to be drawn somewhere).

Answer 7

Neither, as respondent 1 said. Of course it is life, as are all viruses, but only under modern definitions.

Answer 8

Prokaryotic if anything at all, virii have no nucleus. It is hotly debated whether virii are alive or not as they cannot replicate themselves but I would argue that they show us the form life would have taken (or something similar) at abiogenesis. Not only are virii alive, they are very important.