BIOC 2580 Study Guide - Final Guide: Erwin Chargaff, Maurice Wilkins, Fischer Projection
21 Oct 2016
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Emil fischer 1853-1911 ~ nobel prize in chemistry 1902. Studied the analysis, synthesis, and stereochemistry of simple sugars. Fischer projection formula = represent 3d sugar structures on paper vertical bonds = project behind plane and horizontal bonds = project out of plane. Detecting presence and [] of a sugar like glucose using chemical property of reducing and non-reducing. First to isolate dna in 1868, called it nuclein . But vast biological significance not appreciated until 1940s. Found that in all cellular dna s the number of adenosine residues = number of thymidine resides. And the number of guanine residues = number of cytidine residues. A=t and g=c but % of gc and at varies among organisms. X-ray diffraction to identify secondary structure of dna. Chromosomes are extremely long dna molecules, tend to shear and fragment during isolation. Each fragment similar, but not identical, difficult to form well ordered crystals with them.
