Are viruses life?

DaveC426913

But this is not a definition. You've found common properties, granted, but that doesn't define life.

kuzao

dear dave,
you are just arguing semantics!

are you unsatisfied with the grammar of my statement? should i rather say
any entity that contains dna and rna at the same time is to be called life?

or how about 'life:things transcribing and translating'

i do not think that your point is valid. that is as long as we talk about a biological definition of live. as soon as you want to argue the philosophical side you might be right. but then on the other hand your previous attempt to define life would look rather clumsy.

from your previous posts i get that you do share my view, so could you tell me what you dislike about my definition?

by the way last time i checked the molec. micro biology books i usually use called viruses infectious particles.

oh and another thing: until now i met nobody who uses virii. which might be also based on the fact that -ii is the ending for F. and M. latin words ending on -ius. which would naturally mean that virii is nonsense. (that so as long as you dont write normally virius)

alex

DaveC426913

No, I'm unsatisfied that this defines (Earth) life.

Hm. Let me compose my argument...

No. Far too vague. Lots of artificial non-living things transcribe and translate.

kuzao

hmm i wonder what non living things you are refering too when you say there are some which transcribe and translate?

DaveC426913

Computer programs for a start.

junglebeast

Understanding the function of DNA makes it obvious that DNA itself is not necessary for life. It's role is simply to store information in a way that can be copied to allow evolution to occur. DNA is certainly not the only molecule that could potentially fill this purpose.

I believe there has been at least one organism identified on Earth that does not use DNA, although I can't remember the name of it. Anyway, life on other planets almost certainly will not use the exact form of DNA as here on Earth. Moreover, there is no fundamental reason why life must be molecular at all. Life could theoretically be formed out of sub-atomic particles, or even out of virtual building blocks in a computer.

DaveC426913

All of which I would agree with, if he hadn't qaulified it by saying Earth life.

BoomBoom

That is most certainly not the only function of DNA. DNA is essential to cellular function.


How can you be so certain? The "central dogma" could very well be universal.....across the universe. Until we actually find extraterrestrial life, the words "almost certainly" has no substance to it whatsoever.

junglebeast

The same way you can be certain than 10 = x + y has multiple solutions. No experiments are necessary once you understand addition...

kuzao

@ dave
while we seem to agree on the answer our way of comming ot that conclusion seem to be different.

no offense meant but could it be that it is a while ago since you studied molecular biology?

as for transcription and translation, i used these as biological terms. they are defined as coppying dna to rna and then making poly peptides out of rna.
this means that there are actually no artificial 'things', entitys or what ever who translate and transcribe.

@ jungle beast

im not aware of any organism who doesnt contain dna. could you find the name? im curious.

first: of course its not the only molecule but its is certainly the only for EARTH based BIOLOGICAL (some call it organic) life. and that was as, dave pointed out, exactly what i said. are we trying to define what we have here based on 'hard' definitions or are we trying to be philosophical? there is nothing wrong with that, but then the defintion would be so much longer and 'softer'.



second: again there is no offense meant when i say: you didnt had any molecular biology classes, or?
boomboom is right when he says that dna's task are many and not limited to only storing information. expression regulation by dna folding, dna binding and many more ways is big topic in mole. bio.

i do not totaly agree with boomboom on his 'central dogma' theory.
yes it MIGHT. but it might also NOT. we cant say and i proclaim we will never find out because that would require to locate and analyse ALL life (and i mean ALL! not only on earth or in this galaxy) hencefore this is a irrelevant point and futile to discuss.


one thing we should have a common understanding of is the term 'definition'. do we want something which desribes the essence, the principle of life or do we want a definition as lawyers tend to make them ^^ loooong, wound in strange shape so that every possible and impossible exeption is included and useless? (this time the offense to lawyers is intended :P )

alex

p.s. sry for the typos. being dyslexic AND tired is fatal ^^

DaveC426913

Which is a circular argument.

Basically your argument boils down to "life is that which performs biological functions".

DaveC426913

Because amino acids can form a nearly infinite variety of proteins. For DNA to arise the same twice - let alone common - is astronomically unlikely.

Personally, I think it will be very similar, but not the same.

kuzao

@dave

oh far from beeing true. my statement could be read as 'life is what is based on these two functions' (still doesnt sound flashy)

one could see it as a circular argument IF these were the only functions present in organism and thus they could be called the only biological functions.

maybe i should have explained more.
transcription and translation are terms closely realted to presence of rna and dna. thus saying transcription and translation is defining life means presence of dna and rna is defining life.

does this make it more clear to you? do you see now that this is not a 'soft' argument but a very ahrd one? and also not a circular one?

kuzao

first i think its futile to find a defintion for something we dont even know about yet. thats just discussing because we like to read our on writings...

however i agree on the point that it is unlikely. to be exactly the same. but how exactly the same does it has to be to be still called dna? what if it incorporates uracil instead of thymine. could i then still be called dna?

i assume dave then would argue that its not the same thus he was right while boomboom would say hey look it basically the same?

lets dont wander into that realm. there is no merit there.

DaveC426913

No and no.

Translation and transcription do not define life. There are non-living things that translate and transcribe that have nothing to do with DNA or RNA. It is too general.

Your argument is the equivalent of:

All cars have motors. Therefore, the definition of a car is that which has a motor.

kuzao

as i said before transcription and translation are terms of molecular biology and in this context i used them.

do you understand what translation and transcription means?

there are no things which can translate and transcribe and are artificial (at least to my knowledge and if you dont purposly trying to ridicule my argument by saying that a vial where you put in some dna, rna, polymerase and other things should then be called life)

your car argument is a faulty one. if you understand the meaning of transcription and translation you will understand that all things which inherit these two abilities are life. while not all things inhereting a motor are cars.

if you define life via rna and dna or translation and transcription you will as a result get all the things who can 'do' the 'things' most people asscociate with life. like proliferation, metabolism and so on. which is in my opinion a reason to chose this defintion because it avoids to define something by some 'effect' but instead defines by source / reason.

alex

DaveC426913

OK, so let's make that context explicit.

"Life is that which performs biological transcription and translation."

That is circular.