> As you may recall from high school biology, almost every living organism consumes sugar to survive. When it gets right down to it, everything you eat is ultimately converted or digested into single molecules of glucose.
This is an oversimplification. Some bacteria have very weird metabolism. (Or, from the other point of view, some bacteria think that we have a very weird metabolism :) ). They oxidize and reduce different kind of compounds to obtain energy. More info: http://en.wikipedia.org/wiki/Microbial_metabolism
The [extremetech] article has very few details and I think that it's misleading. I can't find the original research article.
There are some interesting details in the video. (Is this a video of this experiment?) Apparently these bacteria use O2 (oxigen) and H2S (hydrogen sulfide). The metabolism is probably like: http://en.wikipedia.org/wiki/Microbial_metabolism#Sulfur_oxi...
It should also be noted that any organism that uses oxidative phosphorylation for metabolism (humans included) technically use "pure energy in the form of electron flow" by having carrier molecules like NADH and FADH2 release electrons into the mitochondrial membrane. The electrons then flow through a few proteins, which use the electrons' energy to create a proton gradient in the mitochondrion, which is then used to create ATP (the "currency" of chemical energy in many cells).
I agree that the tone is a bit sensationalist. It is New Scientist, after all. But note that the article itself makes your point:
> That should not come as a complete surprise, says Kenneth Nealson at the University of Southern California, Los Angeles. We know that life, when you boil it right down, is a flow of electrons: "You eat sugars that have excess electrons, and you breathe in oxygen that willingly takes them." Our cells break down the sugars, and the electrons flow through them in a complex set of chemical reactions until they are passed on to electron-hungry oxygen.
> In the process, cells make ATP, a molecule that acts as an energy storage unit for almost all living things. Moving electrons around is a key part of making ATP. "Life's very clever," says Nealson. "It figures out how to suck electrons out of everything we eat and keep them under control." In most living things, the body packages the electrons up into molecules that can safely carry them through the cells until they are dumped on to oxygen.
> "That's the way we make all our energy and it's the same for every organism on this planet," says Nealson. "Electrons must flow in order for energy to be gained. This is why when someone suffocates another person they are dead within minutes. You have stopped the supply of oxygen, so the electrons can no longer flow."
For that matter even humans have a weird metabolism compared to what the quote says - sugar/glucose is not the only source of energy: https://en.wikipedia.org/wiki/Ketosis
My thoughts exactly, although to be fair, the human body can't survive on ketones alone. Some cells cannot metabolise ketones and rely on glucose produced by the liver to function.
it's an interesting article, and I'd love to understand some of the science behind it. However, this article didn't tell me much of it.
> "This is why when someone suffocates another person they are dead within minutes. You have stopped the supply of oxygen, so the electrons can no longer flow." - Kenneth Nealson at the University of Southern California
Chemical oxidation is not, by any sensible analogy, current flow. It is the exchange of electrons, sure, but the tiny amount of charge flowing anywhere, and the huge masking that occurs in aqueous systems, would reliably prevent any normal consequences of current flow (like a B field) from occurring.
Even what happens in neurons isn't really current flow in any real sense, it is the sympathetic diffusion of ions sideways (in and out of the cell all the way along its length, if the medic who explained this to me was talking any sense) which results in charge at one end of the cell "talking to" charge at the other. Obviously if it were actual "flow", i.e. diffusion, of ions your reaction times would be a lot slower.
> Obviously if it were actual "flow", i.e. diffusion, of ions your reaction times would be a lot slower.
The current in cables work similar way - each electron moves forawrd and back by small distance, never moving far away from the place it started in.
But the information about movement (the elecrtomagnetic field) spreads from one electron to another with the speed of light, so the electrons at the end of cable move as soon as the information gets to them from the begining of the cable.
That's why when you press light switch the light starts almost immediately, despite electrons in cables only moving by millimeters per hour.
I had forgotten about the analogy with electron speed in wires - thank you! I remember my music teacher giving me a very funny look when I pointed it out, and then claiming that electrons must move through wires at the speed of light...when of course it is the electric field "wavefront" that does so.
You're right, its not a great analogy to think about it in terms of current flows, but on the flip side, it totally is about the flow of electrons. When you get right down to the bottom of it, nearly everything boils down to that electron transport chain.
Sure, chemistry is ultimately just quantum mechanics. Oxidation was always explained as an electron exchange in chemistry. It's just not electron flow.
Yes, except in biological systems you can chart out long chains of consecutive electron exchanges such that you end up with electrons transferring between two molecules with the intermediate molecules remaining the same in the end.
In my mind, this makes an analogy to electrical systems, for example a simple battery powered circuit more acceptable.
Still agree that connecting it with 'current' is probably not the best approach.
shewys are typically in fairly carbon-rich environments, so the answer is "probably a lot of things", from acetate to glucose, to more complex stuff like waste nucleotides.
AFAICT, shewys don't typically have CO2 fixation capability. It certainly would be possible to engineer the pathway in and I think people are trying.
Note that assembling most simple carbon compounds, e.g. acetate, glycerol, etc. into higher order carbon compounds is not energy-positive (except for some sugars and fats with the concommitant release of CO2).
I could be mistaken, but I'm actually asking for what these bacteria (e.g., Geobacter) use as a carbon source - that is, where do they get the raw materials to build proteins and DNA? Options are that they reduce CO2 (which could be super cool but surprising for something that lives underground; plants do this in photosynthesis) or that they get their carbon from the environment.
It looks like Geobacter can at least use exogenous acetate[1] but it's not clear what was provided to the lab-grown bacteria described in the article.
The comment that was deleted copied the text from the beginning of the Wikipedia page on Geobacter; I'm pasting it below:
Geobacter... [is capable of oxidizing]... iron, radioactive metals and
petroleum compounds into environmentally benign
carbon dioxide while using iron oxide or other available
metals as electron acceptor.
This seems like something that could one day pose a big problem for civilization. We have all these electrical outlets just sitting around, waiting for someone to request huge amounts of energy on demand. If a lifeform ever evolves to use these effectively, they could spread like wildfire.
Plant leaves are also quite large. If we could hypothetically leave the earth unsupervised for millions of years with the electrical outlets still working, we'd probably return to find lots of macroscopic electric life.
Considering the general lack of a near by water source probably not. Now high tension powerlines could be an option as there out doors and pump out a lot of energy which can be collected on both the small and large scales.
Don't forget it's been a billion years and plant's still don't use green light. For plankton it was reasonable as green does not penetrate as far but on land it's a huge waste.
I used to work in the lab adjacent to ken nealson... Another lab in the department was using this principle for waste water treatment. Stick electrodes in the water, draw current off of an enforced potential, and see what survives under this selective pressure. Turns out its a stable population that is fairly resistant to biotic and abiotic inputs... Just let the biology figure it out. The output water is really clean, too.
> A slightly higher voltage offers an excess of electrons; a slightly lower voltage means the electrode will readily accept electrons from anything willing to pass them off.
...is it just my before-coffee hangovered mind, or they got this completely backwards?! ...would be really sad since NS is one of the few layman friendly decent-quality source of science news :(
Alright, but what kind of life form would create the circuits and the voltage sources to sustain an electric/electronic life-form ecosystem? The equivalent of plants, algae or cyanobacteria.
Anyone have any theories on how this could have evolved? I have to wonder what sorts of minuscule electric currents they're feasting on down their underground.
There's electrochemical gradients just about anywhere... If you have for example stratified rock, there's energy in the differing potentials between the layers.
"In these, they roamed among the stars. They no longer built spaceships, they were spaceships.
But the age of Machine-entities swiftly passed. In their ceaseless experimenting, they had learned to store knowledge in the structure of space itself, and to preserve their thoughts for eternity in frozen lattices of light. They could become creatures of radiation, free at last from the tyranny of matter.
Into pure energy, therefore, they presently tranformed themselves; and on a thousand worlds, the empty shells they had discarded twitched for a while in a mindless dance of death, then crumbled into rust.
Now they were lords of the galaxy, and beyond the reach of time. They could rove at will among the stars, and sink like a subtle mist through the very interstices of space. But despite their godlike powers, they had not wholly forgotten their origin, in the warm slime of a vanished sea."
I'd like to point out that every green plant you see outside your window is getting its energy from pureelectro-magneticradiation! Which I honestly think is a cooler accomplishment. And I would argue that light is just as pure a form of energy as an electric gradient if not more so.
Yes, the fact that a there are bacteria out there doing this is really cool. However, the ridiculous hype science and tech reporter feel the need to put in their articles is just annoying.
To me, this seems interesting because of its potential impact on us rather than an impressive feat of evolution.
We'll call this science fiction, but - imagine doing your wiring on the fly with self-organizing bacteria, or having to worry about bacteria evolved to leach off your circuit board.
Since we think of metal and electricity as very lifeless, the author is right to point out that this seems alien, even if it's an obvious and less-evolved form of life.
What if this "less-evolved" system is actually a step forward in our evolution as species? Because we use a lot of electricity for the machines required to create, maintain (and promote) our food, what if we could just skip that and directly plug the energy into ourselves?
It can be measured; here's a page listing the energy efficiency of various foods: http://www.theoildrum.com/node/6252. It appears it would depend on what we were giving up; if we replace meat with direct energy, we could save around 95%, for instance, but if we replaced grain with electricity we'd save much less, as grain is already fairly efficient.
Average Corn yield is ~160 bushels per acer. 60lb per bushel. An acre is 4,046 square meters. A square meter gets 1kw in full sunlight. Call it 8 hours a day of sunlight. Corn takes 63 to 92 days so you can get 2 yeilds per year in some area. Call it 72 for sweet temptation. 72 * 8 * 4,048 / 160 / 60 = ~242 kwh worth of sunlight per pound of corn.
Note: Solar cells are ~22% efficient but they also work all year.
While this is quite fascinating, I resent the repeated statement that electricity is the purest form of energy. It just seems that way because it's convenient for a technological civilization like ours to sling around. IMO the purest form of energy is kinetic.
These particles mediate the fundamental particle interactions and therefore are the simplest forms of energy possible.
As for whether kinetic energy is the simplest... it's really more of a multiplier on top of existing force carriers rather than an energy on its own. For example: higher energy photons have higher momentum but it's the photon that's the carrier, it just exists at different levels.
"This is why when someone suffocates another person they are dead within minutes. You have stopped the supply of oxygen, so the electrons can no longer flow"
Oh i see, that is what happens. That makes sense now. Didn't know New Scientist has CSI edition too.
This is an oversimplification. Some bacteria have very weird metabolism. (Or, from the other point of view, some bacteria think that we have a very weird metabolism :) ). They oxidize and reduce different kind of compounds to obtain energy. More info: http://en.wikipedia.org/wiki/Microbial_metabolism
The [extremetech] article has very few details and I think that it's misleading. I can't find the original research article.
There are some interesting details in the video. (Is this a video of this experiment?) Apparently these bacteria use O2 (oxigen) and H2S (hydrogen sulfide). The metabolism is probably like: http://en.wikipedia.org/wiki/Microbial_metabolism#Sulfur_oxi...