Cells come from other cells reasoning

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BigDreamPhleb
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Cells come from other cells reasoning

Post by BigDreamPhleb » Thu Jan 22, 2009 12:55 am

Hello,

First I want to say you guys have a great site here.

I was in my Bio 210 class today and going over the cell theory. I understand the theory as:
1.) All organisms are composed of cells.
2.) All cells come from pre-existing cells.
3.) Chemical reactions responsible for life take place within cells.

My question is (and it may be pretty far off the path), if you say all cells come from pre-existing cells, isn't that a "chicken-egg" type of statement? If you follow the path of life back far enough wouldn't you find a cell that didn't come from another cell? If cells are the most basic forms of life then the moment a group of elements and compounds become a cell that event would be the absolute beginning of life wouldn't it?

I'm pretty sure that type of question is outside the scope of a General Biology class, but it's been nagging me all day and I wanted to get some of your thoughts on it.

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MrMistery
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Post by MrMistery » Thu Jan 22, 2009 2:27 am

the idea is that all modern cells come from pre-existing cells (organisms can't magically appear). Of course, in evolutionary time, cells did appear at one time. Of course, making the difference between "cell" and "lipid vesicle with stuff inside" in evolutionary time is next to impossible, but you get the point. Your course wants you to realize that all the cells on the planet now came from other cells.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

BigDreamPhleb
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Re: Cells come from other cells reasoning

Post by BigDreamPhleb » Thu Jan 22, 2009 4:12 am

Thanks MrMistery,

While looking around at links on this site I found an explanation of an experiment. In the 1950s Stanley Miller, and Harold Urey where able to simulate a primitive ocean and atmosphere (or as close as lab equipment would let them). In the experiment they were able to produce several amino acids.

A little research on Wiki found that "In recent years, studies have been made of the amino acid composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated species, assumed to share only the last universal ancestor (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment."

With continued success into origin of life studies, what do you think the chances are that we will be able to synthesize a living cell in the laboratory?

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MrMistery
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Post by MrMistery » Thu Jan 22, 2009 4:55 am

a living cell? That is still a really long time away. I would say we may be able to make a virus fairly soon, but making a cell would require an exhaustive knowledge of its mechanisms, which we are nowhere close to.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

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Re: Cells come from other cells reasoning

Post by JorgeLobo » Tue Jan 27, 2009 3:04 am

Miler's experiments have not been reasonably linked to life's beginnings.
Clearly, as you say, cells must have at some point derived from non-cels and life from non-life. So spontaneous generation happened at some time - just not any more/

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