In the Beginning was Information
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individual catalytic enzyme reactions which follow one ano<strong>the</strong>r in exactly<strong>the</strong> required sequence, and employ just as many intermediate compounds.Adenosin triphosphate (ATP) has some special chemical properties whichenable it to perform important functions. It belongs to <strong>the</strong> group ofnucleotides, comprising adenine, C 5 -sugar, D-ribose, and phosphategroups. When nutrients are oxidised to generate energy, <strong>the</strong> more energyrichATP is formed from adenosin diphosphate (ADP). The energy storedin ATP can <strong>the</strong>n subsequently be utilised by conversion into chemical work(e. g. biosyn<strong>the</strong>sis), mechanical actions (e. g. muscular effort), or osmotictransportation. When this happens, <strong>the</strong> ATP loses one phosphate group, andreverts to ADP. <strong>In</strong> this energy transfer system ATP is thus <strong>the</strong> charged substance,and <strong>the</strong> ADP is neutral. The numerous very complex intermediatechemical steps in this ATP/ADP energy cycle are catalysed by a specificset of enzymes. <strong>In</strong> addition to this general flow of biological energy, <strong>the</strong>reare some very clever special mechanisms for energy conversion.Certain fishes like <strong>the</strong> electric eel can generate electrical pulses of severalhundred volts directly from chemical energy. Similarly, light flashes emittedby some animals and organisms represent converted chemical energy.The bombardier beetle converts <strong>the</strong> chemical energy contained in hydrogenperoxide into explosive pressure and volume changes.Machines constructed for <strong>the</strong> purpose of energy utilisation essentiallyinvolve <strong>the</strong> generation of easily transportable electrical energy in a roundaboutway by first producing heat. Heat Q can only perform useful workW when <strong>the</strong>re is a temperature difference T 2 - T 1 . The <strong>the</strong>oretical maximumamount of work that can be performed by a heat engine, is given by<strong>the</strong> Carnot formula:234W = Q x (T 2 - T 1 )/T 2T 2 can be <strong>the</strong> initial temperature of <strong>the</strong> steam entering a turbine, for example,and T 1 can be <strong>the</strong> exhaust temperature. It follows that large temperaturedifferences are required to produce a reasonable amount of usefulwork. <strong>In</strong> living cells <strong>the</strong> processes for generating energy must be fundamentallydifferent, since all reactions have to take place at <strong>the</strong> temperatureof <strong>the</strong> cell; in o<strong>the</strong>r words, <strong>the</strong> processes must be iso<strong>the</strong>rmic. The refinedenergy concepts realised in cells utilize substances which are unstable toheating, but still achieve exceptionally high degrees of efficiency.The cells: A living cell can be compared with a factory comprising severaldepartments, each of which has a certain number of machines.The work of all <strong>the</strong> cell’s departments and machines iinvolves optimallygeared interrelationships exhibiting planning down to <strong>the</strong> last detail. The end