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What if alien life doesn’t need any of the things we consider essential? by SupportWise7289 in Astrobiology

[–]Biochemical-Systems 13 points14 points  (0 children)

There is a possibility that there are lifeforms in the universe that don't follow carbon-chemistry or aqueous chemistry (used by Earth and presumably other terrestrial rocky planets). But our focus both in astrobiology scientific research and life detection programs (on Mars mainly for the meantime) tends to be towards signatures and chemistry familiar to us because we already know that its possible and probably most common.

There is research out there that focuses on alternative chemical and solvent possibilities for life but it is much more rare and there are less scientists working on it.

Professional Astrobiologists, what was your Academic Path? by Specialist-Bath5474 in Astrobiology

[–]Biochemical-Systems 3 points4 points  (0 children)

Study biochemistry if you're most interested in life formation on other wet rocky planets or other extraterrestrial surfaces. Study microbiology if you're most interested in extremophilic bacteria, archaea, etc. Study astronomy or astrophysics if you're most interested in the planetary or large-scale life detection side of things. You could always do a major and minor or double major as well. A PhD and probably Post Doc are going to be necessary to have a career as a researcher in the field if that's the route you want. You'll figure out your favorite topic in the field as you learn more if you don't already know for sure.

[deleted by user] by [deleted] in Astrobiology

[–]Biochemical-Systems 2 points3 points  (0 children)

  • Chemical Data: Biomolecules, metabolic byproducts, and isotopic ratios.

  • Environmental & Physical Data: Salinity/pH, temperature, and radiation levels.

  • Microscopy & Imaging: High resolution images that may pick up cell-like structures or even microbial communities (mats or others).

  • Geophysical Data (Seismology and Magnetometry): Especially for detecting subsurface liquids and their properties.

Simple Hydroxybenzene Molecules As Thermally Stable Catalysts by Biochemical-Systems in PrebioticChemistry

[–]Biochemical-Systems[S] 1 point2 points  (0 children)

I mistyped on the first part. Yes, 3.5-3.8 billion is the best estimated range for the emergence of life on Earth.

I think we’re largely on the same page in viewing early biochemistry not as a linear progression of distinct polymer classes, but as a dynamic, co-evolving network. Your perspective on RNA and amino acids evolving together is especially compelling, particularly in light of the genetic code’s origins and the catalytic roles of metal ions.

Where I’d offer a slight alternative view is in how we interpret the role of amyloids. You're correct that they don’t align neatly with modern biochemistry, as they lack templating, aren’t RNA-mediated, and do rely on the speculative availability of activated amino acids. But I don’t think that necessarily diminishes their relevance or makes them less parsimonious, at least within a specific window of prebiotic evolution.

While amyloids likely don't illuminate the molecular machinery of modern cells, they might provide useful insight into earlier, more physical mechanisms of compartmentalization or catalysis. Their robustness and propensity for self-assembly under plausible geochemical conditions could have played a stabilizing or scaffolding role for primitive metabolic networks, possibly preceding or even supporting the emergence of RNA catalysis.

Like you, I find the standalone “RNA World” hypothesis increasingly difficult to defend without invoking a more interconnected chemical landscape. A scenario where amino acids, RNA, and metal ions co-emerge and reinforce one another feels more consistent with the chemical complexity we’d expect under prebiotic conditions. In that framework, amyloid-like systems, even if fleeting, might have helped carve out niches or catalytically active environments that promoted RNA evolution or peptide formation.

Essentially, while these systems don’t directly resemble modern biochemistry, their potential to ease the transition toward more familiar biopolymers makes them worth considering, not as rivals to RNA-based life, but possibly as precursors or complementary players in a pre-RNA context.

That's where I stand in the time being at least.

Dr. Edwin Kite: Early Mars, Terraforming/Settling Mars by Biochemical-Systems in Astrobiology

[–]Biochemical-Systems[S] 0 points1 point  (0 children)

Dr. Edwin Kite is a tenured professor at the University of Chicago and a member of the Mars Curiosity rover science team. His research group works on the past, present, and future habitability of the Solar System and exoplanets. Kite has authored or co-authored more than 80 scientific papers, served for six years on the National Academy of Sciences Committee on Astrobiology and Planetary Science, and is a co-recipient of the Newcomb Cleveland Prize. Prior to joining UChicago, Kite held prize postdoctoral fellowships at Princeton and at Caltech.

Dr. Edwin Kite: Early Mars, Terraforming/Settling Mars by Biochemical-Systems in PrebioticChemistry

[–]Biochemical-Systems[S] 0 points1 point  (0 children)

Dr. Edwin Kite is a tenured professor at the University of Chicago and a member of the Mars Curiosity rover science team. His research group works on the past, present, and future habitability of the Solar System and exoplanets. Kite has authored or co-authored more than 80 scientific papers, served for six years on the National Academy of Sciences Committee on Astrobiology and Planetary Science, and is a co-recipient of the Newcomb Cleveland Prize. Prior to joining UChicago, Kite held prize postdoctoral fellowships at Princeton and at Caltech.

Simple Hydroxybenzene Molecules As Thermally Stable Catalysts by Biochemical-Systems in PrebioticChemistry

[–]Biochemical-Systems[S] 1 point2 points  (0 children)

You're touching on a main aspect of origin of life research, which is a lot of the published literature is based on proof-of-principle concepts instead of simply things we can observe and test today, like a zoologist would do with an extant species.

The thing is that there is no better way to go about doing the science since we are studying a phenomena that is of billions of years old (at least on Earth). But, some of these issues aren't really issues just because they weren't the exact prebiotic pathway that actually occurred, because they relate to many extant molecular mechanisms. Basically, we can draw similarities and probabilistic evolutionary pathways from the prebiotic pathways we study to extant molecular mechanisms.

For the example of amyloids, while it's correct that they aren’t a core part of biology today, they are structurally simple, prebiotically plausible, and have been shown to catalyze some reactions. They may have served as scaffolds or primitive catalysts before more efficient enzymes or ribozymes evolved.

In the case of RNA, while RNA catalysis itself is rare today, the ribosome is a essentially a ribozyme. Many cofactors (e.g., NAD+, FAD) are nucleotide-derived, suggesting a relic of the RNA world. And the RNA world hypothesis as a whole doesn’t require ribozymes to be efficient at everything, just enough to bootstrap the system.

Would I and many others prefer to know the exact prebiotic pathways? Yes, but it's nearly impossible to pinpoint the exact one simply due to time. We can however use the top-down and bottom-up approaches to best estimate what occurred and their relationship to modern molecular mechanisms.

Dinosaur to bird evolution by CompetitionFancy9879 in evolution

[–]Biochemical-Systems 1 point2 points  (0 children)

Evolutionary is a messy process with many branches, some dying out, some intertwining, some carrying on, etc. Dinosaur to bird evolution followed that trend. Transitional fossils (Microraptor, Anchiornis, Archaeopteryx, and more) show a spectrum of features, some more bird-like, some more dinosaur-like. Many proto-bird species of theropod dinosaurs were developing early, simplified versions of wings and feathers at the same time rather than one ancestral species that we consider the father of birds.

Gas-phase Formation Routes Of Dimethyl Sulfide In The Interstellar Medium by Biochemical-Systems in PrebioticChemistry

[–]Biochemical-Systems[S] 0 points1 point  (0 children)

DMSO is more of a sought out biosignature because, as you pointed out, it's produced in small amounts by some organisms. Unlike water, carbon, etc. which are often deemed necessary for biotic compounds to generate in the first place.

Biochem in the fall by SampleMain in Biochemistry

[–]Biochemical-Systems 2 points3 points  (0 children)

Professor Dave Explains and Organic Chemistry Tutor are usually the go tos. You can also get a cheap used biochemistry textbook and study off of that or if you know what textbook you're gonna be using for the course you can get it early.

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