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Homochirality is a uniformity of chirality, or handedness.Objects are chiral when they cannot be superposed on their mirror images. For example, the left and right hands of a human are approximately mirror images of each other but are not their own mirror images, so they are chiral.
The reason of the prevalence of homochirality in living organisms is currently unknown and is often connected to the origin of life itself. Whether homochirality emerged before or after life is currently unknown, but many researchers believe that homochirality could have been a result of amplification of extremely small chiral asymmetries.
Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?
In biology, homochirality is a common property of amino acids and carbohydrates. The chiral protein-making amino acids, which are translated through the ribosome from genetic coding, occur in the L form. However, D-amino acids are also found in nature. The monosaccharides (carbohydrate-units) are commonly found in D-configuration.
Homochirality is an obvious characteristic of life on Earth, yet extraterrestrial samples contain largely racemic compounds. [7] It is not known whether homochirality existed before life, whether the building blocks of life must have this particular chirality, or whether life must be homochiral at all. [8] [9] What do all the unknown proteins do?
Walker has studied the possible mechanisms of the origin of homochirality, which is a key problem in the origin of life. [ 10 ] [ 11 ] [ 12 ] In her research she has used several models such as the Sandars polymerization model, the Langevin equation , and the activation-polymerization-epimerization-depolymerization (APED) model to imitate ...
The origin of this homochirality in biology is the subject of much debate. [13] Most scientists believe that Earth life's "choice" of chirality was purely random, and that if carbon-based life forms exist elsewhere in the universe, their chemistry could theoretically have opposite chirality.
The following is a list of notable unsolved problems grouped into broad areas of physics. [1]Some of the major unsolved problems in physics are theoretical, meaning that existing theories seem incapable of explaining a certain observed phenomenon or experimental result.