BIOCH200 Lecture Notes - Erwin Chargaff, Chemical Polarity, Cell Nucleus

• School: University of Alberta
• Department: Biochemistry
• Course: BIOCH200
• Professor: Walter Dixon

Document Summary

2014: the primary structure of dna is the sequence of nucleotide residues. *dna forms a double-helix structure: *the most common form of dna is the b-form of dna. *alternating major and minor groves of dna and the helix is twisted in the right-hand direction. *10 base pairs per turn: dnas helical structure deduce by watson and crick with help from erwin. Chargaff: *ratio of a:t and c:g were always approximately 1, a + g = t + c. Number of purines = number of pyrimidines: hydrogen bonds, by polar interactions, much weaker than covalent bonds. *in fact, hydrogen bonds aren"t actually bonds but rather a sharing/tug-of-war of electrons. *they may be weak but altogether, they make for a significant amount of stabilizing force. *however, h-bonds are not the most important contributor to the stability of dna structure: *the biggest player is base stacking (the primary stabilizing force)