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Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing heterocycles in nature. [1]
Purines are biologically synthesized as nucleotides and in particular as ribotides, i.e. bases attached to ribose 5-phosphate.Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which is the first compound in the pathway to have a completely formed purine ring system.
Science fiction (sometimes shortened to sci-fi or abbreviated SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, and extraterrestrial life.
"A science fiction story is a story built around human beings, with a human problem, and a human solution, which would not have happened at all without its scientific content." [13] Basil Davenport. 1955. "Science fiction is fiction based upon some imagined development of science, or upon the extrapolation of a tendency in society." [14] Edmund ...
The late 19th century witnessed a new generation of writers, such as J.-H. Rosny aîné, utilizing science and pseudoscience for purely fictional purposes. [15] This marked a significant departure from their predecessors, who employed the conjectural element as a pretext, following in the footsteps of Savinian Cyrano de Bergerac's utopian, Jonathan Swift's satires, and Camille Flammarion's ...
Science in science fiction is the study or of how science is portrayed in works of science fiction, including novels, stories, and films. It covers a large range of topics. Hard science fiction is based on engineering or the "hard" sciences (for example, physics, astronomy, or chemistry).
Golden Age of Science Fiction — a period of the 1940s during which the science fiction genre gained wide public attention and many classic science fiction stories were published. New Wave science fiction — characterised by a high degree of experimentation, both in form and in content.
Uric acid crystallizes in the lactam form, [5] with computational chemistry also indicating that tautomer to be the most stable. [6] Uric acid is a diprotic acid with pK a1 = 5.4 and pK a2 = 10.3. [7] At physiological pH, urate predominates in solution. [medical citation needed]