The Role of Analogy

Leatherdale, W. H. The Role of Analogy, Model andMetaphor in Science. Amsterdam North Holland, 1974. 

Orgill, M., and G. M. Bodner (2005) The role of analogies in chemistry teaching. In The Chemists Guide to Effective Teaching, eds. T. G. Greenbowe, N. Pienta, and M. M. Cooper, pp. 90-95. Upper Saddle River, NJ Pearson. 

Duit, R. (1991). On the role of analogies and metaphors in learning science. Science Education, 75, 649-672. 

Heywood, D. and Parker, J. 2010. The role of analogies in learning. The Pedagogy cf Physical Science. Contemporary Trends and Issues in Science Education, Vol. 38, pp. 39-64... 

Electromagnetism (Faraday-Maxwell historical episode) Maxwell s magnetic vortex model of electromagnetic interaction [did not feature in the classroom talk] e.g. the role of analogies in the development of Maxwell s theory of electromagnetism... 

Unsaturated fluorocarbons are much more reactive toward nucleophiles than then hydrocarbon counterparts owing to fluorme s ability to both stabihze carban ions and mductively increase the electrophihcity of multiple bonds and aromatic nngs Nucleophihc attack dominates the chemistry of unsaturated fluorocarbons, and the role of fluonde ion in fluorocarbon chemistry is analogous to that of the proton in hydrocarbon chemistry [129] Like the related electrophilic reactions for hydrocarbons, there are fluonde-promoted isomenzations and dimenzations (equation 9), oligomenzations (equation 10), additions (equation 11), and amomc Fnedel-Crafts alkylations (equation 12) that all proceed via carbamomc intermediates [729 7 7]... 

With X = RN the C-1 electrophilic center is most active, and five-membered heterocycles 131 are generated (69ZOR1179). With X = O there is a competition between C-1 and C-3 electrophilic centers, the role of the latter increasing on going to sulfur analogs (X = S) in accord with a decrease in the - -M effect in this series (81UK1252). 

Like the Strecker synthesis, the Ugi reaction also involves a nucleophilic addition to an imine as the crucial step in which the stereogenic center of an a-amino acid derivative is formed4. The Ugi reaction, also denoted as a four-component condensation (A), is related to the older Passerini reaction5 (B) in an analogous fashion as the Strecker synthesis is to cyanohydrin formation. In both the Ugi and the Passerini reaction, an isocyanide takes the role of cyanide. 

Fluorouracil (5-fluorouracil, 5-FU, Fig. 5) represents an early example of rational drag design in that it originated from the observation that tumor cells, especially from gut, incorporate radiolabeled uracil more efficiently into DNA than normal cells. 5-FU is a fluorinated pyrimidine analog that must be activated metabolically. In the cells 5-FU is converted to 5-fluoro-2>deoxyuridine-monophosphate (FdUMP). This metabolite inhibits thymidilate synthase which catalyses the conversion of uridylate (dUMP) to thymidilate (dTMP) whereby methylenetetrahydrofo-late plays the role of the carbon-donating cofactor. The reduced folate cofactor occupies an allosteric site of... 

Controlled-potential (potentiostatic) techniques deal with the study of charge-transfer processes at the electrode-solution interface, and are based on dynamic (no zero current) situations. Here, the electrode potential is being used to derive an electron-transfer reaction and the resultant current is measured. The role of the potential is analogous to that of the wavelength in optical measurements. Such a controllable parameter can be viewed as electron pressure, which forces the chemical species to gain or lose an electron (reduction or oxidation, respectively). 

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