Exception to Characteristics of Life.
January 19, 2005 at 3:01 am #301
I have a bio quiz question that I cant seem to find the answer to and was wondering if any of you gifted individuals could help me out.
The question is:
What has all of the characteristics of life (ie, grows, reproduces, is made of cells) except does not have the last characteristic, which is “has DNA or RNA”?
January 19, 2005 at 6:32 am #19055
January 19, 2005 at 6:52 am #19056
do viruses really ‘grow’ though….
January 19, 2005 at 3:21 pm #19057
That’s true…knee-jerk reaction. Viruses have been up for debate for a long time.
January 20, 2005 at 3:25 pm #19065
Virus was my first guess too, but they contain RNA. So it must be something else. (This is a tough one!)
January 21, 2005 at 4:34 am #190802810712Participantquote trus:
I think, we should first decide that in what sense should we take the words cell, grow, reproduce. It can be any thing – nonliving also.But , if it,s a question in bioquiz then can it be a non living thing?
January 21, 2005 at 4:48 am #19081
red blood cells?
January 21, 2005 at 11:46 am #19086
I’m not sure but can it be PRION? I do not have so much knowledge about it but i know that it has neither DNA nor RNA. It is made of only protein.
January 22, 2005 at 8:32 am #19102bioguyParticipant
January 22, 2005 at 7:00 pm #19112
prions do not grow, but they do carry a small bit of genetic material.
January 23, 2005 at 4:26 am #19121
Anyone seen the virus in the movie Andromeda Strain?
January 27, 2005 at 8:42 pm #19179quote mithrilhack:
No I haven’t – is it a good movie?
January 28, 2005 at 8:36 pm #19203
It’s this crystal space virus that feeds on energy and matter. It grows and grows and is seemingly unstoppable. Well, I won’t ruin the story 🙂
January 30, 2005 at 1:27 am #19221quote trus:
A virus – Still up in the air
February 1, 2005 at 8:52 am #19283wauporParticipant
I have far less bio knowledge.
I think virus is not living thing.
I do also think red blood cell is no DNA.
It has no nucleus for increasing the ratio of surface area to volume.
But I don’t know whether the DNA present in the cytoplasm or not.
February 1, 2005 at 3:29 pm #19291quote waupor:
It has many of the things that make something living – It needs a host to survive – even though small pox can survive for years in the environment without a host (if I’m wrong please correct me; I would like to know)
February 1, 2005 at 4:04 pm #19294
someone correct me if im wrong but viruses seem like a form between living and nonliving. arent they? they need host to survive, they have sensivity to heat and they are not immortal means that they carry characteristics of life. But they turn to cristal form without a host. (not forever but for some time of course) which seems like a characteristic of nonliving.
So, are they living or nonliving or what else ❓
February 1, 2005 at 6:38 pm #19298
THAT is a good question, and one that science continues to debate. At what point can you start making exceptions to the characteristics of living vs. non-living materials? If you make an exception for viruses will we also have to excuse prions…
February 1, 2005 at 8:33 pm #19302
Note the original question states it’s made of cells. The last time I looked the virus isn’t a self-contained self maintaining entity….there’s really no maintanence.
February 1, 2005 at 11:00 pm #19319
In one of the books I’ve read, it says:” The things which can do respiration are considered to be LIVING. the others are considered to be NON-LIVING.”
Do you think that respiration is exactly the point which living and non-living things can be classified? It sounds a bit strange to me. 🙄
what do you think?
February 2, 2005 at 6:08 am #19328
Hello everyone. Glad to see that this question has sparked some conversation. While I still havent discovered the answer to this riddle, let me help those of you that are wondering whether a virus is alive for dead. The 6th qualification that needs to be met for the object to be considered alive is “to contain DNA or RNA”. Viruses contain RNA.
February 2, 2005 at 8:40 am #19331wauporParticipantquote Poison:
Then how about PC’s CPU ? Do you think that they can thinking themself ? Are they a living things ?
February 2, 2005 at 3:36 pm #19334quote waupor:
I couldnt get the question. Viruses are made or organic material arent they? what is the relationship between PC and virus?
February 2, 2005 at 8:21 pm #19339
Well you could argue that pc’s (robots) are living. They consume electricity and metals. They have intelligence(somewhat). They reproduce by assembling clones of themselves and in other cases making better copies and improving upon existing designs.
February 2, 2005 at 10:38 pm #19343
Are robots made of organic material? Or do they carry DNA or RNA? No. But viruses do. Dont they?
February 3, 2005 at 12:15 am #19344
Viruses carry RNA, true.
But viruses are not made of cells, a stipulation clearly stated in the modern accepted definition of life.
If you want to call viruses life, then you must first confront the entire biological community to petition for the definition of life to be changed. Or at least redefined.
February 3, 2005 at 4:16 pm #19351quote biostudent84:
I’m not trying to call viruses life. I just want someone to persuade me.
February 3, 2005 at 5:05 pm #19352canalonParticipant
Virus can carry both RNA or DNA, but it cannot self replicate, it needs a cell replication mechanism to copy and multiply its genetic materia and to synthesize its enveloppe. They are basically genetic material wrapped in a membrane, without any machinery.
Prions do not carry genetic materials, they are proteins that change the folding of normal proteins (produced and coded by a cell) into the pathogenic form in self catalytic process.
Are they alive ❓ The limit is hard to draw.
If it was not for the “made of cells” conditions, crystals could have been a good answer, they grows using only free material in the environment, without the need of a complex external machinery (i.e. a cell). And they are indeed making new copies of themselves. They were even supposed to have been one of the possible origin of life, though it is note the most highly favoured. And they are definetly non liveng entities.
February 3, 2005 at 10:54 pm #19363
you know, trus, you might want to ask your biology teacher that one. It would be interesting to see what he/she thinks. Also, did you get that quiz back yet?
That’s a good question, and as far as I can tell, a Virus is as close as it comes. the next thing I’d guess is prokaryotic cells, but those have DNA. I’m curious to find out, so if you get any idea as to what it might be, please tell us.
February 4, 2005 at 12:02 am #19366
Thank you all for your explanations. Now they really seem to me like non-living.
But I have one more question. (I think I asked it before). Can ‘respiration’ be the point where living and non-living differ? (I mean the exact point)
February 4, 2005 at 4:44 am #19369
While it is not included in the actual definition of life, I would have yo say yes, you might be right on that one. It would be hard to judge unless we can find a packet of chemicals that undergoes respiration but fails to meet the parameters of life…or one that does meet said parameters, but fail to respire.
February 5, 2005 at 5:01 am #19381
that’s a little but of an paradox, isn’t it? after all, don’t living living things need to be able to go under respiration for energy? so how can something live and not undergo respiration? It’s like what they say, “When you breathe, you respire. When you don’t breathe, you expire.”
February 6, 2005 at 2:29 am #19386MaxwellParticipant
Viruses are not considered to be alive for two reasons:
1) They do not produce their own energy
2) They cannot reproduce on their own. They need the help of a host cell’s machinery to produce more viruses.
Viruses also cannot be the answer to the riddle because, as stated by biostudent, they are not made of cells. Additionally, all viruses have some sort of genetic material in the form of either RNA or DNA depending on the virus. The RNA or DNA can be either single or double stranded.
February 7, 2005 at 11:32 am #19401
I don’t see any way for this to have an answer and not be a trick question. All cells that grow and reproduce have RNA at least. I’m not sure if there’s any true life without DNA, but if so it will have RNA.
The answer could be something like a beehive, but the bees have DNA and RNA and are essential for the reproduction and growth…it sounds like a trick question of some kind.
February 10, 2005 at 2:36 pm #19496
Right… can any living thing replicate without RNA or DNA?
February 10, 2005 at 2:53 pm #19498quote thank.darwin:
Actually, yes. DNA sequencers do it all the time.
February 10, 2005 at 9:12 pm #19512
What are DNA sequencers? (I’m only in my first year of biology -we haven’t gone over anything like that)
February 13, 2005 at 10:03 pm #19581
DNA sequencers are machines that read DNA and then report to scientists what the sequence of bases is in the DNA.
They do not replicate themselves; nor are they alive. What they do is replicate strands of DNA that are in the machine in order to read it.
Take a look at this website:
February 15, 2005 at 9:29 pm #19640
Thank-you RobJim, that helped a lot!
February 19, 2005 at 5:15 pm #19700
DNA sequencers sound like they’re a special type of protein. if so, then wouldn’t they have at least some DNa or RNA, because I thought proteins were made from ammino acids?
February 19, 2005 at 7:35 pm #19705
Read the info at the link and the posting itself. Both will tell you the sequencer is machine.
February 19, 2005 at 10:10 pm #19708
oops. my bad. I was thinking about helicases.
March 3, 2005 at 11:09 pm #20011MrMisteryParticipant
The viruses have been up for debate for a long time: nobody was able to determin if they are alive or not, so in the present they are called infectious entities. It is also true that viruses can contain DNA or RNA but they do not have their own methabolism nor are they capable of reproduction. But think of it: are viruses more alive than the printer or the computer monitor? Of course they are. Also, they are less alive than a bird or a toad. So, my personal opinion is that if you look at life as angradual state then both viruses and prions(which, from what i know do not contain DNA or RNA) can be alive, but at different levels. This is how i see this problem. I don’t know if anyone understands anything from what I just wrote, I hope yes.
By the way, someone mentioned red blood cells. You first have to consider that red blood cells have a nucleus at all animals except mamals. But, i consider them as being part of life and not life itself. If a cell is alive than can you consider the mithocondrion inside it alive(maybe it’s not the best example since it is a known fact that mithocondrion are primitive bacteria which have come into symbiothis with the cell a long long time ago- anyway, you see my point)
March 5, 2005 at 11:36 am #20055LeeParticipant
virus i think
March 5, 2005 at 1:48 pm #20056
I believe that viruses are not considered alive, as they don’t fit the definition of life.
March 5, 2005 at 1:49 pm #20058
yes RobJim thats right. We discussed this so far.
March 6, 2005 at 7:39 am #20094Dr.DoomParticipant
Viruses do have genetic material (ssRNA, ssDNA …etc). Prions are proteins; they do multiple through protein-protein. All other animate objects have genetic material (yes even fungus); therefore, the cloest thing may be a prion, but i don’t know if you can consider that as an animate object.
March 6, 2005 at 4:53 pm #20103
Right Dr.Doom… 😀
March 6, 2005 at 5:52 pm #20105quote Dr.Doom:
I guess we can’t. 🙂
March 7, 2005 at 8:27 pm #20167
Of course virus is alive.
They reproduce because they are automated to do so, but so are animals (such as humans) and animals are considered alive.
They have no choice but to invade cells and so on but our will is just as limited as theirs (just that our will can handle more complex situations).
And for the riddle: Bee hives are made of cells and they grow. And they kind of reproduce (new hives are built).
March 7, 2005 at 8:35 pm #20170quote Wilmer:
There’s more to the definition of life than reproduction =)
Viruses are not made of cells, they do not arise from cells of the same species as themselves, and they do not enact the process of respiration.
Whether or not a virus is a living being is still under debate by the biology community. No official verdict has been accepted yet =)
March 7, 2005 at 9:02 pm #20175
I think that “has to be made of cells” is a silly concept for life. 😛
The first living organism probably wasn’t a cell (even thought all cells are it’s children).
It is not likely that membranes and all the proteins nessecary just popped up from nowhere. The first strain of DNA or RNA or whatever can’t have been complex.
The first thing to live was the first thing that started to copy itself. Those who started feeding before copying and protecting their DNA (or RNA or whatever) with membranes were less likely to be broken by radiaton.
This is just what I think. Don’t listen to me if you are writing something for school.
March 7, 2005 at 10:40 pm #20189biologyistehcoolParticipantquote Wilmer:
me too lol 😀
March 7, 2005 at 11:24 pm #20193JamesParticipant
Our classifictions of life are dominated from the majority of ‘living’ organisms we have so far observed. If we classed life as being made of cells, or those that do our ‘life processes’ etc, then if we met aliens, perhaps not carbon based, which were not made of cells or did our ‘life processes’, then we wouldn’t class them as alive, even if they were free moving and even intelligent organisms. Our classifictions should not be rigid, I’m sure that if we came across intelligent organisms on a far planet, despite not doing all of our life processes, we would say they were alive. So why don’t we classes viruses as alive?
March 8, 2005 at 4:10 pm #20215
We discussed wheather viruses are alive or not. I think you can hava a look at them.
March 8, 2005 at 8:27 pm #20222MrMisteryParticipant
The aliens we would meet will deffinetly have their own methabolism. Viruses do not. That is a major point in why they are not considered alive(by the way, I also consider viruses alive, just less alive than other things)
March 9, 2005 at 12:33 pm #20258
Atleast ONE of the aliens on another planet would have to eat and grow. All the other aliens could live like viruses.
March 9, 2005 at 1:06 pm #20262quote Wilmer:
Read the research journals, textbooks and articles published by biologists. Whether or not you think it is “silly” is not a major concern to the Virologists and Taxonomists that are being paid big bucks to determine whether or not viruses are alive. When those researchers senior to us are completely certain whether or not they live, they will let us know.
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