A tárgy természete... A biológiai tudományok egysége Molekuláris, organizmikus és populációs megközelítés Érdekes de NEHÉZ Aki nem akar figyelni, az menjen ki! Vizsga: írásban. Utóvizsga: szóban Vizsganyag: az előadások (órai jegyzet és diasorozat, cikkgyűjtenény)
Az élet kettős természete Eörs Szathmáry Eötvös University Collegium Budapest
Miért kettős? Homeosztázis—disszipatív—anyagcsere Egyirányú vezérlés és öröklődés A láng és az öröklődő tulajdonságokkal rendelkező sejt különbözősége
Great thinkers on the nature of life Gottfried Leibniz Freeman Dyson John Maynard Smith Erwin Schrödinger
Leibniz Az „isteni gépek végtelenül oszthatónak tűnnek A gépszerű működés a „molekuláris” dimenzióban is érvényesül
Schrödinger A gén mint aperiodikus kristály Az entrópia alacsony szintjének fenntartása állandó munkavégzést igényel
Maynard Smith Anyagcsere és homeosztázis Genetikai szabályozás Az evolvabilitást az utóbbi adja
Freeman Dyson Az élet kettős eredete Először az anyagcsere és a homeosztázis, nukleinsvak nélkül A gének mint a rendszer parazitái jelenhettek meg
An irreversible system A B
A reversible reaction A B Le Chatelier-Braun principle
A reversible, closed reaction system
Reaction systems A closed, reversible cycle An open, almost reversible system
Closed and open systems Alul: a stacionárius állapot (steady state)
The skeleton of sugar decomposition
Chemical cycles are metabolic engines The cycle as a whole is a catalyst The Noble prize of Szent- Györgyi was awarded for catalysis by fumaric acid Krebs has recognized the whole cycle Enzymes are superimposed on the metabolic cycle
A simple chemical cycle It is formally a unit composed of a closed and an open part Acts as a catalys
Engines operate in cycles, and are hence are dynamically stable
Tibor Gánti Born in 1933 Chemical engineer Patents in industrial biochemistry (artificial metabolism) Syntheses using the controlled operation of enzymatic reaction networks First book on molecular biology in Hungary (1966)
The first edition of the Principles A serious book in a popular science disguise (1971) There was no other way to publish Proposal included the term “chemoton” ‘reductionist’ and ‘vitalist’ at the same time!
The investigation of life criteria: absolute criteria 1.Inherent unity 2.Metabolism 3.Inherent stability 4.Information carrying subsystem 5.Processes regulated and controlled by a programme VERBAL AND PHENOMENOLOGICAL
Quest for a biological minimal system Chemical supersystem Should be conceptually as simple as possible Must not necessarily be realizable in its simplest form Comparison with other elementary units (such as the elementary cell in crystallography) FORMAL AND EXACT
The latest edition: OUP 2003 After several editions in Hungarian Two previous books (the Principles and Contra Crick) plus one essay Essays appreciating the biological and philosophical importance
Enzymes and cycle stoichiometry Very important: the cyclic process sign with the number of turns
Structures built of amphipathic molecules A two-dimensional fluid
A self-reproducing vesicle (1978) Metabolism and reproduction No genetic subsystem
Pathways of supersystem evolution boundary template metabolism M BM B B TB T M TM T M B TM B T INFRABIOLOGICAL SYSTEMS
Organisation of chemical systems into a supersystem (1974) CHEMOTON: a particular supersystem which is also a biological minimal system
Gánti’s chemoton model ALL THREE SUBSYSTEMS ARE AUTOCATALYTIC template copying metabolism membrane growth
The assembly of RNA structures Combinatorial assembly of RNA structures Submitted to selection for function between chemotons 1979
The channelled assembly of ribozymes (1983) The presence of substrates gives guidance to ribozyme assembly Good enzymes and bad enzymes will affect the fitness of the chemotons
Venter: professional but trivial (synthetic biology)
The monograph (Kluwer 2003)
The chemoton symbol
Evolution towards a Borromean arrangement? Chemoton symbolBorromean rings