{"id":317,"date":"2023-11-20T17:57:04","date_gmt":"2023-11-20T17:57:04","guid":{"rendered":"https:\/\/cellandcelldivision.com\/?p=317"},"modified":"2023-11-20T17:57:04","modified_gmt":"2023-11-20T17:57:04","slug":"page-17","status":"publish","type":"post","link":"https:\/\/cellandcelldivision.com\/?p=317","title":{"rendered":"Page 17"},"content":{"rendered":"\n

disposal much more numerous data from the well-developed by that time
physics, astronomy, geology, cosmology and other sciences having
relevance to the problem. He has taken into account the achievements of
biochemistry, cytology, molecular biology and genetics as well as the
results from the ever more precise light and electron microscopy, revealing
the structure of a variety of crystals, polypeptides and nucleic acids. All this
has helped him a lot to hold into the positions of the evolutionary
development of living organisms and to formulate clearly the putative
history of life beginning into three major stages: from the atom to the
molecule; from the molecule to the polymer; from the polymer to the
organism.<\/strong>
The model of J. Watson and F. Crick (1953) establishing the DNA
double helix structure and the role of nucleic acids in the reproduction of
living organisms have given Bernal the grounds to accept that life on Earth
is a function of the interaction of nucleic acids and proteins. This model will
be discussed in the following Chapter 2, Section 2.7. (Nucleicacids).
In contrast to Oparin, as a physicist and crystallographer Bernal
assumed that it is not the coacervates, but the adsorption of clay and soil
particles which was the cause for the condensation of organic substances
that has later on led to emergence of life. This hypothesis, however, did not
meet recognition as he himself admitted.
A hope that the main principle accounting for the differences between
living and non-living matter was raised by the discovery of molecular
asymmetry known as molecular chirality. The term \u201cchirality\u201d was
introduced by W. Thomson (Lord Kelvin) in 1884, which comes from the
Greek word for \u201chand\u201d. According to Gutina and Kuzmin (1990) the most
correct term is molecular stereoisomery.<\/strong>
Stereoisomers are compounds which being of an identical chemical
composition and the same molecular weight display differing properties. As a
result of the spatial distribution of atoms their molecules are in two forms \u2014 D
and L, which turn the plane of polarized light to the right and left respectively;
the one being a mirror image of the other, just like two hands of the human
(Fig. 1\u20131).
Let us give some examples. Of the two forms of phenylalanine the Lisomer
causes grave diseases while its D-isomer is harmless; L-adrenalin
possesses a stronger hormonal action than its D-isomer.
It is thought that molecular asymmetry is attributable only to natural
organic compounds. All amino acids making up the proteins are L-forms
which upon hydrolysis in soft conditions preserve their optical activity. If
amino acids however are synthesized in laboratory conditions then optically
inactive forms are obtained. These are the so called racemic mixtures<\/strong>
consisting of equimolar quantities of D- and L-stereoisomers and are
denoted by the symbols DL.<\/p>\n","protected":false},"excerpt":{"rendered":"

disposal much more numerous data from the well-developed by that timephysics, astronomy, geology, cosmology and other sciences havingrelevance to the problem. He has taken into account the achievements ofbiochemistry, cytology, molecular biology and genetics as well as theresults from the ever more precise light and electron microscopy, revealingthe structure of a variety of crystals, polypeptides […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[6],"tags":[],"class_list":["post-317","post","type-post","status-publish","format-standard","hentry","category-book"],"_links":{"self":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts\/317","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=317"}],"version-history":[{"count":1,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts\/317\/revisions"}],"predecessor-version":[{"id":318,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts\/317\/revisions\/318"}],"wp:attachment":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=317"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=317"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}