70 Self and the Phenomenon of Life
b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity “9x6”- Callahan MP, Smith KE, Cleaves HJ II, et al. (2011) Carbonaceous meteorites
contain a wide range of extraterrestrial nucleobases. Proc Natl Acad Sci USA
108: 13995–13998. - Chemical and Engineering News (2007), 85: 41–42.
- Miller SL. (1953) A production of amino acids under possible primitive
earth conditions. Science 117: 528–529. - Oró J, Kimball AP. (1961) Synthesis of purines under possible primitive
earth conditions. I. Adenine from hydrogen cyanide. Arch Bio Chem Bio-
phys 94: 217–227. - Oró J, Kamat SS. (1961) Amino-acid synthesis from hydrogen cyanide
under possible primitive earth conditions. Nature 190: 442–443; Oró J.
(1967) Stages and mechanisms of prebiological organic synthesis. In Fox
SW. ed. Origins of Prebiological Systems and of Their Molecular Matrices.
Academic Press, New York, pp. 137–171. - Unlike DNA chains which are rigid except to coil around and form a dou-
ble helix, RNA chains are highly flexible so that the various regions of a
single chain can come together by base-pairing to produce highly irregular,
three-dimensional structures unique for each RNA molecule (reminiscent
of protein folding). Examples of RNA enzymes include self-splicing RNA
from the protozoan Tetrahymena, and RNAseP, a nucleoprotein whose
RNA part is responsible for RNA-cutting activity (nuclease) during the for-
mation of tRNA. See: Kruger K, Grabowski PJ, Zaug AJ, et al. (1982) Auto
excision and auto cyclization of the ribosomal RNA intervening sequence of
Tetrahymena. Cell 31: 147–157; Guerrier-Takada C, Gardiner K, Marsh T,
et al. (1983) The RNA moiety of ribonuclease P is the catalytic subunit of
the enzyme. Cell 35: 849–857. - Gilbert W. (1986) The RNA World. Nature 319: 618.
- White HB. (1976) Coenzymes as fossils of an earlier metabolic state. J Mol
Evolution 7: 101–104. - Bartel DP, Szostak JW. (1993) Isolation of new ribozymes from a large
pool of random sequences. Science 261: 1411–1418; Zhang B, Cech TR.
(1997) Peptide bond formation by in vitro selected ribozymes. Nature
390: 96–100; Unrau PJ, Bartel DP. (1998) RNA-catalysed nucleotide
synthesis. Nature 395: 260–263; Bartel DP, Unrau PJ. (1999) Construct-
ing an RNA world. Trends in Cell Biol 9: M9–M13; Lee N, Bessho Y,