User Tools

    To create and edit articles, please register and log-in

Main Menu

Main menu
Click categories to expand


A-Z listingplugin-autotooltip__plain plugin-autotooltip_bigA-Z listing

This is an alphabetical index of all content pages.


Other categories

Utilities

Contact
Register

Also see

Importance Ratings
News
Legal
Donate/Sponsor
Curator's rationale


Wikenigma supports:


Feeds etc
rss / xml feed
sitemap file
A-Z listing (archived)


Auto-Translate Site
Indexed under : Life Sciences / Life Itself

Wikenigma - an Encyclopedia of Unknowns Wikenigma - an Encyclopedia of the Unknown

Homochirality

Symmetry is a fundamental aspect of nature. For example, certain molecules exist in two forms which are symmetrical mirror images of each other. They are called chiral molecules. Common chemical synthesis generally produces equal amounts of the two forms of chiral molecules. In living systems, however, this symmetry is broken. Naturally occurring proteins are composed of L-amino acids but not D-forms, whereas DNA and RNA contain only D-sugars. How did this homochirality originally form in the context of the origin of life is a giant conundrum and has received much attention.

Source :A testable hypothesis on the possible role of electron spin in the origin of bio-homochirality arXiv, 2020.

The recognition of chiral (i.e. 'handed') molecules goes back to the time of Louis Pasteur. Since then, exhaustive investigations in a wide range of organisms has shown 100% consistence in the homochirality ('same handed-ness') of biological chemicals.

There are many theories on how this might have evolved (chemical, mathematical, quantum-based etc. etc.) but none is currently accepted as a definitive answer.

Note: There are also questions about whether a 'mirror image' of life, with all the complex chemicals reversed, could exist.

Further info at Wikipedia

Importance Rating


    Share this page :

Dear reader : Do you have any suggestions for the site's content?

Ideas for new topics, and suggested additions / corrections for old ones, are always welcome.

If you have skills or interests in a particular field, and have suggestions for Wikenigma, get in touch !


Or, if you'd like to become a regular contributor . . . request a login password. Registered users can edit the entire content of the site, and also create new pages.

( The 'Notes for contributors' section in the main menu has further information and guidelines etc.)

Automatic Translation

You are currently viewing an auto-translated version of Wikenigma

Please be aware that no automatic translation engines are 100% accurate, and so the auto-translated content will very probably feature errors and omissions.

Nevertheless, Wikenigma hopes that the translated content will help to attract a wider global audience.

Show another (random) article

DOKUWIKI IMPLEMENTATION DESIGN BY UNIV.ORG.UK JUNE 2022