21–30 of 120 posts
This is great, if you have significant amounts of free oxygen to work with, which early earth evidently did not. Would be interesting to see if anaerobic metabolism could also occur without cellular confinement.
Earlier quoted context omitted.
Not as much as you might think. We've found amino acids almost everywhere we look, including astroids [1]. It seems that the building blocks of life pretty naturally and readily form. Which is a pretty strong indicator that life is likely fairly common outside earth. [1] https://www.nasa.gov/news-release/nasas-asteroid-bennu-sampl...
The amino acids that can be found everywhere include ten of the simpler amino-acids that are used in proteins (glycine, the 2 acids, the 3 branched, alanine, proline and the 2 alcohols). The other 11 amino-acids from proteins have never been found where life does not exist. They are more complex and they seem to have been developed by living beings long after the appearance of life and the appearance of the genetic c…
Reminds me of the Gamma Forest at Brookhaven National Labs. From 1961 thru 1978 they irradiated a section of the pine barrens forest with a cesium-137 source just to see what would happen. It sterilized the soil and hardly anything grows there, almost 50 years later. https://maps.app.goo.gl/pJYr6qiZnMdVwLJS6 https://www.atlasobscura.com/places/brookhaven-gamma-forest https://www.youtube.com/watch?v=GsuiLxcDuHY&t=925s
That's a bit odd - why wouldn't wind blown non-sterile organic matter from the surrounding forest re-colonize the area?
It feels next would be trying isolate the component that make CO2. Try to use smaller sample. Put them under microscope, etc.
Maybe it's the very molecules that the live cells were using, just doing their thing without the cells. Cells concentrate things by confining them in a small volume, but otoh, if you have damp particles, the thin water layer on the particles would be a kind of confining space, with the added advantage of surface area to exchange gases with.
This is great, if you have significant amounts of free oxygen to work with, which early earth evidently did not. Would be interesting to see if anaerobic metabolism could also occur without cellular confinement.
Earlier quoted context omitted.
The amino acids that can be found everywhere include ten of the simpler amino-acids that are used in proteins (glycine, the 2 acids, the 3 branched, alanine, proline and the 2 alcohols). The other 11 amino-acids from proteins have never been found where life does not exist. They are more complex and they seem to have been developed by living beings long after the appearance of life and the appearance of the genetic c…
I don't see the left handed aspect as necessary for life. To me this just suggests our common ancestor for life on earth made use of this chirality. Another group of organisms somewhere else could have evolved from an ancestor that makes use of right handed chirality. Or one that is hand-blind.
It seems that the choice between left-handed and right-handed amino-acids was random.
However, it is unlikely that other kinds of life forms could use both kinds indiscriminately, because mixing them creates difficulties in the assembling of polymers. So it is likely that amino-acids produced by some extra-terrestrial life form would also be predominantly of only one orientation, but it could happen to be the right-handed variant.
Moreover, extra-terrestrial life forms could use very different complex amino-acids, because there are much more of those than the 11 that have been added to the simple amino-acids in the terrestrial proteins.
Reminds me of the Gamma Forest at Brookhaven National Labs. From 1961 thru 1978 they irradiated a section of the pine barrens forest with a cesium-137 source just to see what would happen. It sterilized the soil and hardly anything grows there, almost 50 years later. https://maps.app.goo.gl/pJYr6qiZnMdVwLJS6 https://www.atlasobscura.com/places/brookhaven-gamma-forest https://www.youtube.com/watch?v=GsuiLxcDuHY&t=925s
that seems pretty major exaggeration
https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.0800...
Theory on the emergence of photosynthesis whereby chlorophyll-like structures first evolved from harvesting heat rather than light: https://www.inaturalist.org/journal/mjpapay/45240-the-first-...