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Author Topic:   Is everything made of the same material?
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 7 of 45 (401371)
05-19-2007 1:09 PM
Reply to: Message 5 by taylor_31
05-19-2007 12:33 PM


If life is made of roughly twenty proteins, then the chain holding them together should be very long, correct?
Er, that's not quite it. There are 20 different amino acids, and proteins are made out of these aminos chained together.
It's like having a box with 20 different kinds of Legos in it, and you can make whatever you want by hooking the Legos together, and you basically have as many of each kind of Lego that you need.
And when you put a certain number of Legos together in a specific order, that's a specific protein with a specific function in the body. DNA is basically a set of instructions a cell uses to put the Legos together to get the proteins that it needs.
So if each "link" in the chain has twenty possibilities, then the total number of possibilities grows very high. (20 x 20 x 20 x 20 etc.)
Yes, that's true. Theoretically there's a very large number of possible polypeptides (which is a way of describing what proteins are, referring to the chemical bonds between each amino acid, called "peptide bonds.") In reality, living things employ only a very small number of all the possible proteins, because the majority of "random" proteins have no chemical function at all.
It's mind-boggling (for me) to think that proteins can have that much effect on life.
They are life, basically. Or rather - life is your body doing chemistry in response to environment, and proteins are how that chemistry is done.
Once the proteins are there, what happens? How do they directly effect the life process?
Once a chain of amino acids is formed, it "folds up" based on electrical charges. That folding creates a specific shape, and it's the shape of the protein that determines its chemical properties. Some proteins become structural elements - building blocks, if you will, out of which your body is constructed - but many others form enzymes, which are catalysts (chemicals that cause other chemicals to react with each other without consuming or changing the catalyst in the process). Enzymes govern the chemical reactions your body is doing to stay alive. For instance, when your body breaks down food into usable materials and energy, enzymes are at work doing that.

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 Message 5 by taylor_31, posted 05-19-2007 12:33 PM taylor_31 has replied

Replies to this message:
 Message 10 by taylor_31, posted 05-20-2007 1:42 AM crashfrog has replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 9 of 45 (401373)
05-19-2007 1:23 PM
Reply to: Message 6 by taylor_31
05-19-2007 1:01 PM


So even the nucleotides of DNA are formed of carbon, nitrogen, and oxygen, and hydrogen, right?
Plus phosphorus, but basically, yeah. Those four elements you named constitute the majority of a living thing, they're the heavy lifters if you will, but most of the other elements have uses in living things. For instance, iron is important to your blood (and why it's red), calcium is important to your bones, sodium and chloride are important for nerves, etc.
A broader question is, is everything in the known universe made of elements from the periodic table?
Without getting into astrophysics - nobody knows what "dark matter" is made of, but aside from that, everything we know about is made of atoms (unless we're talking about what atoms are made of) and every different "kind" of atom is an element on the Periodic table. When we discover a new kind of atom, the lucky SOB who discovered it gets to name it, and we add it to the table.
All atoms are made of the same three kinds of particles - protons, neutrons, and electrons, and then protons and neutrons are made up of even more elementary particles, and we think that's as far down as it goes. It's kind of a mess.

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 Message 6 by taylor_31, posted 05-19-2007 1:01 PM taylor_31 has not replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 13 of 45 (401511)
05-20-2007 12:59 PM
Reply to: Message 10 by taylor_31
05-20-2007 1:42 AM


I just wanted to pop in with an example of what you were talking about.
Okay, so each protein is made of twenty different kinds of amino acids. The exact number making up the protein, however, doesn't have to be exactly twenty.
Yes, exactly. For instance, the protein hemoglobin, which you may recognize as the protein responsible for the oxygen-carrying capacity (and red color) of blood, is comprised of four protein subgroups, each containing about 145 amino acids.
Furthermore, every transitional from the bacteria to the redwood is a result of random mutation in the DNA instructions and natural selection, and each transitional is a fully functional species. Is this correct?
Basically. There was one big change, about a billion years ago, that led to a big difference between the cells of bacteria and the cells of plants and animals. While plant and animal cells have membrane-bound organelles, like the nucleus of the cell where DNA is located:
bacterial cells don't. Their DNA and cellular processes just happen "out in the open" within the cell:
The reason for the development of membrane-bound, "organized" cells (which we call "eukaryotic") from cells that had no internal membrane-bound organelles (which we call "prokaryotic") was something called "endosymbiosis."
What happened was, in the distant past, an organism like a bacteria literally absorbed a smaller, different organism into its cell, but instead of digesting it, they because dependent on each other. We believe this happened twice - first, an organism was absorbed that became known as mitochondria, which act as little "batteries" inside cells, using and storing power; then, one of the descendants of these composite-organisms absorbed a second endosymbiote that was able to generate power from sunlight. These were the ancestors of chloroplasts, and the cells that had absorbed chloroplasts became the ancestors of green plants.
We know this happened because, while plant and animal cells keep their DNA - the DNA that describes your body, the color of your hair and eyes, etc - in the cell nucleus, mitochondria (which both plants and animals have) and chloroplasts (which animals don't have) have their own DNA. Other cell organelles don't. This tells us that mitochondria and chloroplasts were once free-roaming individual organisms in their own right before they found a new home within our cells.
Sorry that was so complicated, and it's really beyond the scope of your question, but I wanted to show you that, while random mutation and natural selection are the primary forces of evolutionary change, sometimes big changes happen that aren't specifically about mutation and selection. If you don't feel like you "got it", don't worry too much about it.

This message is a reply to:
 Message 10 by taylor_31, posted 05-20-2007 1:42 AM taylor_31 has replied

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 Message 16 by taylor_31, posted 05-20-2007 3:06 PM crashfrog has replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 19 of 45 (401610)
05-20-2007 10:30 PM
Reply to: Message 16 by taylor_31
05-20-2007 3:06 PM


If the bacteria-like organism "absorbed" the smaller organism, how did the smaller organism appear in the descendants?
Organisms that small reproduce by cell division; the smaller endosymbiotes simply divided along with their hosts.
My superficial guess is that the mitochondria and chloroplasts have their own reproductive process, and when the bacteria reproduce, the mitochondria and chloroplasts do the same somehow. Is this right?
Nowadays, the reproduction of mitochondria and chloroplasts is regulated by the host cell itself, but that's basically it. Cells eventually evolved the ability to stimulate mitochondrial reproduction in response to greater energy needs, but I imagine in the beginning, mitochondria reproduced at probably they greatest rate they could without overwhelming the host cell.

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 Message 16 by taylor_31, posted 05-20-2007 3:06 PM taylor_31 has not replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 29 of 45 (409823)
07-11-2007 2:15 PM
Reply to: Message 23 by IamJoseph
07-11-2007 6:03 AM


the dust of earth's matter does not result in life by itself, even given eons of light years.
This statement is nonsensical. Light years are a measurement unit of distance, not time.
IOW, if life could emerge here in prevailing over one million adverse conditions - it aught to prevail over 2 million adverse conditions elsewhere.
This is your same old argument, as nonsensical as ever. Life requires Earthlike conditions to evolve and survive. That life has no evolved under conditions that are not Earth-like hardly contradicts this premise; indeed, it supports it.

This message is a reply to:
 Message 23 by IamJoseph, posted 07-11-2007 6:03 AM IamJoseph has replied

Replies to this message:
 Message 30 by IamJoseph, posted 07-11-2007 9:29 PM crashfrog has replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 32 of 45 (409876)
07-11-2007 9:58 PM
Reply to: Message 30 by IamJoseph
07-11-2007 9:29 PM


These are inter-changeable, relative to its context.
No, they're not in any way interchangeable. It's as much nonsense to say "eons of light-years" as it is to say "a month of miles."
The life seen in a swamp, for example, did not initiate solely because of earth-like conditions, is my point. Further, to survive, conditions have to be intergrated and designed in a way the subject is receptive. A mother can support an off-spring, but the emerging life is condusive - signifying a hovering program which incorporates both. Life is involuntary.
That makes absolutely no sense at all. Can you restate?

This message is a reply to:
 Message 30 by IamJoseph, posted 07-11-2007 9:29 PM IamJoseph has replied

Replies to this message:
 Message 33 by IamJoseph, posted 07-11-2007 10:28 PM crashfrog has replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 34 of 45 (409883)
07-11-2007 11:16 PM
Reply to: Message 33 by IamJoseph
07-11-2007 10:28 PM


The cluster of Virgo is not merely so many miles away, but expressed in the time it takes that light to reach earth. That is why it is termed light YEARS.
Yes. That's why light-years is a measurement of distance, equal to 5.87910^12 miles, and not a unit of time. It's a unit of distance because it's used to measure distance.
Life is not intiated only by earthly matters.
Says you. Why is it that you can't seem to marshal any evidence for that?

This message is a reply to:
 Message 33 by IamJoseph, posted 07-11-2007 10:28 PM IamJoseph has replied

Replies to this message:
 Message 35 by IamJoseph, posted 07-12-2007 2:25 AM crashfrog has replied

  
crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 40 of 45 (409935)
07-12-2007 10:45 AM
Reply to: Message 35 by IamJoseph
07-12-2007 2:25 AM


A light year distance = 1 year light travel.
Right. It's a distance.
What about this is hard to understand? The unit of time you're looking for is called the "year."

This message is a reply to:
 Message 35 by IamJoseph, posted 07-12-2007 2:25 AM IamJoseph has not replied

  
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