Engineering Papers⌕ Search

Engineering topics

Ponnamperuma, C.

Publications and source records attributed to Ponnamperuma, C..

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Experimental investigation on the origin of the genetic code.

A simple model of interacting complex systems of species is tested to assess the binding behavior of monomeric nucleic acid and protein components during evolution. Nine representative amino acids are immobilized by the formation of an amide linkage on a prepared chromatographic support. Selective binding of ribonucleoside 5-phosphates in these amino acids is achieved under standardized conditions, and a site-binding model is derived to characterize the binding. It is shown that the binding behavior of the reactants during nucleic acid-protein interactions depends on the nature of the base and the amino acid. The results of the study are assessed as useful for the interpretation of more complex nucleic acid-protein systems and of their role in the evolution of the cell.

Saxinger, C.↗
NASA NTRS1971

Chemical evolution and the origin of life; Proceedings of the Third International Conference, Pont-a-Mousson, France, April 19-25, 1970. Volume 1 - Molecular evolution.

The present state of investigations on the origin of life is surveyed together with the current state of molecular paleontology. General and theoretical subjects discussed include an energetic approach to prebiological chemistry, the recognition of description and function in chemical reaction networks, and the origin and development of optical activity of bio-organic compounds on the primordial earth. Other fields considered are the syntheses of small molecules, oligomers and polymers; photochemical processes; the origin of biological structures; primitive biochemistry and biology; and exobiology. Individual items are abstracted in this issue.

Buvet, R.↗
NASA NTRS1971

Experiments in Jovian atmosphere.

A 1000 ml reaction vessel, fitted with a stopcock, two joints for the electrodes, and a connecting joint, was used in the investigation. The flask, which has a cold finger at the bottom, was filled with an equimolar mixture of anhydrous methane and ammonia. The electrodes were adjusted to provide a gap of about 0.8 cm between them so that the current flowing through the electrodes was about 0.5 mA and a continuous spark could be observed. The operation was continued for 20 hr. The analysis of the reaction products showed the formation of amino nitriles under the conditions of the investigation.

Chadha, M. S.↗
NASA NTRS1971

The role of phosphates in chemical evolution.

The hypohydrous thermal reaction between inorganic phosphates and nucleoside was investigated. The products of the reactions have been identified, and an attempt has been made to determine the mechanism. It was found that orthophosphates can be readily converted into condensed phosphates which are effective phosphorylating agents. Thermal polymerization of inorganic orthophosphates at moderate temperature as a general source of polyphosphates might have provided efficient phosphorylation and condensing agents for primordial syntheses.

Ponnamperuma, C.↗
NASA NTRS1971

Polymer formation in a simulated Jovian atmosphere.

Experimental investigation in which an attempt was made to fractionate the polymeric substances in a simulated Jovian atmosphere according to molecular weight, and to characterize them. It is pointed out that the substance obtained by discharge in methane and ammonia has often been assumed to be the substance responsible for the red color of Jupiter. The deposit formed on the reaction vessel really looks reddish. When the substance was fractionated according to the molecular weight, the color was darker the larger the molecular weight. However, the spectrum of the color was, whether by absorption or by the combination of scattering and fluorescence, indistinguishable regardless of the molecular weight of the fraction. In addition, the apparent color changes when the concentration varies. It would not be simple to identify the red substance in Jupiter.

Noda, H.↗
NASA NTRS1971

The role of ionizing radiation in primordial organic synthesis.

Attempt to reveal how ionizing radiation may have been effective in producing the molecules necessary for life. In examining the sequence of events leading to the appearance of the first organisms the problem is considered in two parts: the formation of the small molecules such as amino acids, purines, pyrimidines, and carbohydrates; and the condensation of these molecules to give rise to polypeptides and polynucleotides. It is concluded that in the accumulation of organic compounds on the early earth ionizing radiation was not only a substantial part of the available energy, but was also an effective form of energy.

Ponnamperuma, C.↗
NASA NTRS1971

Primordial organic chemistry and the origin of life.

Aspects of Darwinian revolution are discussed together with spontaneous generation, the inorganic chemical evolution, the primitive atmosphere, and interstellar matter. The significance of the change of the earth's reducing atmosphere to an atmosphere with oxidizing characteristics is considered. Experiments regarding the abiogenic synthesis of nucleic acids and proteins are reported. It was found that micromolecules can be formed in simulation experiments. The condensation reaction taking place in the presence of water was studied together with the condensation reaction taking place in the relative absence of water or under hypohydrous conditions. Jupiter simulation studies were conducted, and lunar and meteorite material was analyzed.

Ponnamperuma, C.↗
NASA NTRS1970

The coming search for life on Mars

Extraterrestrial life hypotheses, citing astronomical considerations, inorganic chemical evolution and prebiotic synthesis with emphasis on Mars exploration for microorganisms

Klein, H. P.↗