Total Posts:4|Showing Posts:1-4
Jump to topic:

Origins of Homochirality

ebuc
Posts: 1,850
Add as Friend
Challenge to a Debate
Send a Message
12/26/2017 2:17:37 PM
Posted: 3 weeks ago
..."The scientific driving force for this work arises from an interest in understanding the origin of life, because the homochirality of biological molecules is a signature of life."...

https://www.ncbi.nlm.nih.gov...

..."Short of constructing a Time Machine, we have no way of elucidating precisely the chain of events that led to life on earth today. What we may do instead is highlight the modern experimental and theoretical work that has attempted to probe these questions. After a brief discussion of the first question, this review focuses primarily on the second of the two questions raised earlier: the discussion of plausible mechanisms for the evolution of molecular homochirality as exemplified by the d-sugars and l-amino acids found in living organisms today."...
ebuc
Posts: 1,850
Add as Friend
Challenge to a Debate
Send a Message
12/30/2017 4:54:58 PM
Posted: 3 weeks ago
https://phys.org...

......"For me, the most exciting thing is that this mechanism shows that homochirality is really a biosignature of life, a 100% signature, and should be expected anywhere life emerges," said Goldenfeld. "So for example, we just learned that there is a global ocean of liquid water under the ice of Enceladus ... I think that looking for homochirality in the organic molecules that have been detected there would be a fantastic way to look for life there."

"There are other models, and they may be correct for the origin of homochirality on earth, if you can prove that those prerequisites existed during the emergence of life," said Jafarpour. "But whether those foundations exist or not, for life that emerged anywhere in the universe, you'd expect that it would have self-replication, and our model says that's enough to get homochirality."

The model relies on mathematical and computational techniques that were not available in Frank's time. It takes into account the chance events involving individual molecules"which chiral self-replicator happens to find its next substrate first. The detailed statistics built into the model reveal that if self-replication is occurring efficiently enough, this incidental advantage can grow into dominance of one chirality over the other. The forerunner of this mathematical mechanism came from Biancalani's previous work on how chance events influence the foraging patterns of ant colonies.

Goldenfeld attributes part of their success to the interdisciplinary environment of the IGB and of the Institute for Universal Biology (IUB), a member of the NASA Astrobiology Institute. "If we hadn't been in this environment, we wouldn't have been so prepared to think about this problem; we might have just stuck with ants, and never made the jump to realizing that we can apply this to this origin of life problem," he said.

The work leads to a key conclusion: since homochirality depends only on the basic principles of life, it is expected to appear wherever life emerges, regardless of the surrounding conditions.

Read more at: https://phys.org...
ebuc
Posts: 1,850
Add as Friend
Challenge to a Debate
Send a Message
12/30/2017 5:02:23 PM
Posted: 3 weeks ago
https://robertlovespi.net...
..."The similar polyhedron below, however, features an overall "twist," causing it to qualify as a chiral polyhedron. In its mirror-image (not shown, unless you use a mirror to make it visible), the "twisting" goes in the opposite direction. The direction of rotation would be reversed as well, of course, in a reflected image.:...

The cubo-octahedron via Fullers Jitterbug twists/torques left and right ergo handed-ness,

This leads to left and right skew icosahedral subdivisions ergo 31 left and 31 right-skew great circles derivatives.

http://www.rwgrayprojects.com...
Dirty.Harry
Posts: 2,419
Add as Friend
Challenge to a Debate
Send a Message
1/20/2018 4:01:01 PM
Posted: 1 day ago
At 12/30/2017 5:02:23 PM, ebuc wrote:
https://robertlovespi.net...
..."The similar polyhedron below, however, features an overall "twist," causing it to qualify as a chiral polyhedron. In its mirror-image (not shown, unless you use a mirror to make it visible), the "twisting" goes in the opposite direction. The direction of rotation would be reversed as well, of course, in a reflected image.:...

The cubo-octahedron via Fullers Jitterbug twists/torques left and right ergo handed-ness,

This leads to left and right skew icosahedral subdivisions ergo 31 left and 31 right-skew great circles derivatives.

http://www.rwgrayprojects.com...

More horse sh!t? don't you ever get tired of everyone (yes it's everyone) either ignoring you or ridiculing you?