Is There A Living Thing With NO CELLS?

[SgtSlaughter]

My Bio Teacher (Mr. Gregor) will give me an "A" if I can prove that there is a living thing with no cells.
They have to share the characteristics of a living thing. Can anyone help me? No a Virus is not an answer I’ve tried.
Homeostasis
Organization
Metabolism
Growth
Adaptation to surroundings
Response to stimuli
Reproduction
and Evolution
Try your Best I’ll try to report every day.

[Jones]

Not possible. Unless you would go far enough to say a soul is a living thing, or an aura, or something like that.

[mith]

http://en.wikipedia.org/wiki/Non-cellular_life

Other than that, you might want to consider robotic forms of life such as nanobots which don’t really exist yet. I think probably your teach was trying to prove a point.

[Draco]

Thats not possible.

[MrMistery]

I’ve heard of Mimivirus before. It’s a virus that has a very basic and incomplete metabolism. But nevertheless it has it. that is why some postulated that maybe, just maybe cells are but what a primitive virus-like organism evolved into
However, currently one of the conditions for something to be called alive is to be made of cells. You will need to earn your A through another method

[Jones]

Yeah but even if it were a nanobot or something like that it’s not really living at all. It’s just running.

[SgtSlaughter]

Yeah I thought it was easy but it’s impossible.
thanks.

[SgtSlaughter]

My info is wrong they need…
-A Universal Genetic Code
-To be able to Reproduce
-To be able to Evolve
-To be able to Growth and Development
-The use of materials Energy
-Respond to their Environment
-Cellular organization
-And to maintain an Internal Stability
thats what my book says anyway.

[Darby]

If that is the actual list, your teacher has set you to fail – "Universal Genetic Code" only exists if you assume that all life on other planets also is DNA-based (kind of like how the U.S. always wins the baseball World Series), which is silly at the start, and cellular organization without cells – what’s that even mean?

[SgtSlaughter]

Yes but there is no proof of life on other planets yet. The cellular organization would be the characteristic that would be cast aside.

[MrMistery]

@darby
Well since there is no known life on other planets the definition stands. We have no idea how life would be on other planets, so right now we can only make a definition of the organisms we do know.
However, "Universal Genetic Code" is not such a good remark. There are organisms with slightly different genetic codes, like some species of Tetrahimena, Paramecium and Mycoplasma. I don’t think your teacher is arguing that a Paramecium is not alive…

[SgtSlaughter]

Yea probably not.

[SgtSlaughter]

@MrMistery thanks for that Mimivirus idea that just might work. I will tell you after I hear his response.

[SgtSlaughter]

well the mimivirus was a fail for a few defects in it ways of life

[EmmVeePee]

Cell Theory states all living organisms are made from cells, if I remember correctly.

[genovese]

To give you a chance of acquiring an A, your teacher could have asked you to name a functioning cell that was not alive.

[MrMistery]

what would be a correct answer to that? Plant cells that die, like those in cork? Botanists still call them cells, but if you ask me, they are simply leftover walls. Or maybe a RBC or a sieve tube element? If you ask me they are still alive… I don’t think your question has an answer either

[genovese]

Yes, I had a RBC in mind which is without genetic material. Why do you say that a RBC is alive?

[MrMistery]

cause it has metabolism and protein synthesis. Very low ones, but still. And it has an electrically charged membrane. It is alive because it has to be destroyed in 3 months, as it cannot live for long without a nucleus, even at that metabolism.

[genovese]

I thought genetic material was a prerequisite for life.

Is there RNA floating around in the RBCs or is the low metabolism being carried out using old enzymes which are taking a bit of time(3months) to be used up?

When a person dies, the hair and nails continue to grow for some time due to some slow metabolism going on but the body taken as a whole is still considered to be dead is it not?

[MrMistery]

Genetic material is a prerequisite of life, but a cell can nevertheless be alive without genetic material. Take the case of a sieve tube element if you don’t like RBC: the adjacent cell gives it all the proteins needed to survive for a long time and carry out all the functions it needs, although it looses some organelles. If that isn’t ultraspecialised life, i don’t know what is.

The way I found it in all books is that the RBC does have a low rate of protein synthesis and a low rate of energetic metabolism. Plus, as I said, I regard as indubitable proof of its vitality the fact that its membrane is polarized, something completely absent in dead cells.

BTW, is that nail stuff true? I always thought it was some sort of urban mith.

[canalon]

http://www.bmj.com/cgi/content/short/335/7633/1288

[genovese]

After so many years of believing in rubbish I am pleased to have been corrected on the hair and nail stuff.

On the issue of RBCs, I am still not clear where the RBC gets its enzymes from to carry out metabolism. Your sieve tube element (I will have to look this one up) sounds like a person being kept alive on a ventilator and being fed artificially. Turn the ventilator off and you see that they were dead all the time. Can that really be called life?

[MrMistery]

about the nails, i think we came to a similar conclusion a while back.

About the RBC and sieve tube element, I guess I said all I have to say. If you don’t consider them alive, then we’ll agree to disagree.
BTW, could platelets do as a dead functioning cell? Cause they are not cells, but they are dead and functioning..

[genovese]

I would be more than happy to call a circulating RBC ‘a dying cell on its last breath lasting 120 days’.

[MrMistery]

well that’s kinda what I was saying…

[hanhan2008]

Virus IS a good answer. Maybe prion is another answer.

[MrMistery]

sorry, neither of them is alive. See your introductory biology book if you don’t believe me

[MichaelXY]

quote genovese:

I would be more than happy to call a circulating RBC ‘a dying cell on its last breath lasting 120 days’.

I ran this question by my Bio instructor. He kinda agreed with your definition, but he sorta waivered on it. I could tell the question made him go Hmm.

[genovese]

The problem with Biology is that there isn’t an adequate definition of "Life".
There are always exceptions to be found.

A definition of life for me would simply state the ability of a collection of molecules to replicate and to act as a catalyst. Ie RNA alone would qualify as life. So in my definition
viruses would also have to be included just as any other ‘parasite’ which we see currently see as being alive, but which cannot survive without a host .

[MichaelXY]

Yeah, I guess there will always be a difference of opinion. People arre always telling me to get a life. I guess synthesis of protein is not good enough for them 🙂

[Darwin420]

Hahaha classic biology teacher method. My grade 12 bio teacher did a similar thing, he said anyone to make a lazer beam that can burn a piece of paper out of a lazer pointer would get an A. He is clearly proving a point, he is saying that, because living things without cells does not exist.

Sorry budday.

[sonawanes61]

are yaar life originated frm cell so how can their be organism alive without cell

[genovese]

Which came first, the cell wall or the molecules which provide the chemistry for life?
The chicken or the egg?

[Author]

Posts