Forums

ForumsWorld Events, Politics, Religion, Etc.

Edge Of Life

Posted May 18, '14 at 7:51am

Kennethhartanto

Kennethhartanto

248 posts

Starting a new thread as a way to kill boredom............................

So, do you guys believe virus, prions and RNA's living? i have read multiple article on wikipedia that seems to show different sides to this problem, but no sides have really won

 

Posted May 18, '14 at 8:12am

09philj

09philj

2,680 posts

Viruses and prions aren't alive, but they almost are. Essentially, they are complex proteins; a strand of RNA, a complex protein wrapped in a shell of simpler protein.

 

Posted May 18, '14 at 5:26pm

HahiHa

HahiHa

5,792 posts

Knight

What would your definition of life be?

Prions are proteins that contain no genetic information, the only thing close to a living being it does is replicate; likely by molecular interactions at the right spot, but it seems the procedure is still unknown. To me, this is not life; just an interacting protein sequence.

RNA is a molecule. It can act as both genetic coder and enzyme, so it important to life; but I don't consider it alive.

Viruses are likely more difficult to categorize... they are replicating units containing both proteins and genetic molecules, and are subject to selection pressures; yet they have no metabolism and cannot replicate alone. I think I would consider it not alive in the traditional sense, but certainly as a class of biological units that are on the verge of life.
Who knows, maybe they are the oldest "living fossils", maybe they arose at the same time as the very first living cells without making the last step towards life?

 

Posted May 18, '14 at 6:17pm

Freakenstein

Freakenstein

9,662 posts

Moderator

Viruses would be classified as living if they could reproduce by themselves, as the rest of all organisms can do. Seeing as how they require other organisms to complete this process, they are just shy of classified as being alive. They have everything else, but not that.

Yet ironically, viruses win at life, even though they aren't alive, because some viruses have been found at age 65 million.

 

Posted May 19, '14 at 3:40am

Kennethhartanto

Kennethhartanto

248 posts

What would your definition of life be?


Personally, i would consider anything than can reproduce and replicate itself and have a detailed substructure to be "alive".

Anyway i have found the contradiction in what wikipedia said. what do you think this :

. In particular, it is sometimes found that the Hadean eon is subdivided into the Cryptic era and Basin Groups 1-9 (which collectively make up the Pre-Nectarian), and the Nectarian and Lower Imbrian. The first lifeforms (self replicating RNA molecules, see RNA world hypothesis) may have evolved on earth around 4 bya during this era.


.....meant? because according to the definition of life in 09philj's link, the bolded sentence directly contradicts this
 

Posted May 19, '14 at 5:14am

HahiHa

HahiHa

5,792 posts

Knight

Personally, i would consider anything than can reproduce and replicate itself and have a detailed substructure to be "alive".

1) What about obligate parasites that need a host to reproduce?

- IMO, Viruses rely on the replication machinery of a living cell to reproduce, while parasites have their own reproductive organs; they simply rely on other factors like resources or heat.

2) Define "detailed substructure". Are the structure proteins making up a virus' shell too simple for life?
 

Posted May 19, '14 at 9:27am

Kennethhartanto

Kennethhartanto

248 posts

1) What about obligate parasites that need a host to reproduce?


I would consider obligate parasites (viruses) alive, simply because it has the ability to reproduce, even if if he used other cells to replicate. other reasons as to why i take such stance is because i have been taught that the basic purpose of life for any organism is to reproduce and to propagate itself using whatever means necessary.

2) Define "detailed substructure". Are the structure proteins making up a virus' shell too simple for life?


a detailed substructure is, as it names suggest, a very complex inside structure of something. that "something" must have a way to maintain that complexity ( in normal conditions) and to keep it from breaking apart into simpler components. It may be better to define this as having a negative entropy, as most of anything alive is far more complex than anything not living or were once alive

a virus shell is far, far more complex than anything that is not alive. a shell of numerous proteins and fat which combine to make the bi-layer membrane is very complex and consist of several micro structures like docking proteins that add the apparent complexity of a viruses shell
 

Posted May 19, '14 at 9:44am

HahiHa

HahiHa

5,792 posts

Knight

I would consider obligate parasites (viruses) alive,

Sidenote: I do not consider viruses to be parasites, but rather pathogen agents. An obligate parasite is for example a tapeworm.

And while reproduction is of course important to continuing life, I personally do not consider the mere fact of replicating to be sufficient in and on itself. The difference of being an organism with its own cells and metabolism that needs a host, compared to a structure that needs something else for basically everything and lacks any metabolic process or any kind of machinery, really, is big enough to draw the line. But that's just me.

a virus shell is far, far more complex than anything that is not alive. a shell of numerous proteins and fat which combine to make the bi-layer membrane is very complex and consist of several micro structures like docking proteins that add the apparent complexity of a viruses shell

There are also far more simple viruses out there. What about those?
 

Posted May 19, '14 at 10:47am

09philj

09philj

2,680 posts

far more simple viruses


At their most simple, RNA in a protein coat.
 

Posted May 19, '14 at 11:01am

Kennethhartanto

Kennethhartanto

248 posts

I do not consider viruses to be parasites, but rather pathogen agents. An obligate parasite is for example a tapeworm.


Well we have a disagreement here, because i was taught that virus ARE obligate parasites. He defined "obligate parasites" as anything that requires a host to reproduce.

And while reproduction is of course important to continuing life, I personally do not consider the mere fact of replicating to be sufficient in and on itself


Which is why i added detailed substructure and negative entropy to the mix.

The difference of being an organism with its own cells and metabolism that needs a host, compared to a structure that needs something else for basically everything and lacks any metabolic process or any kind of machinery, really, is big enough to draw the line.


The difference are big, but in my opinion not good enough to disqualify virus as a living object. Because it has a pretty detailed subsystem under the microscope.

There are also far more simple viruses out there. What about those?


All virus have docking proteins and bi-layer semipermeabel membrane, it forms the shell of all viruses
 
Reply to Edge Of Life

You must be logged in to post a reply!