Biochemistry 2280A Midterm: Machlaughlin key points.docx
16 Apr 2015
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Explain the chemical structure of nucleic acid polymers, without memorizing the structures of the nitrogenous bases. Nucleoside: ribose w. n-glyosidic bond at 1" to a nitrogenous base. Nucleotide: above + a phosphate group (monophosphate) at the 5" carbon of ribose. Deoxynuclotide: ribose w. the 1" base, the 2" carbon has 2 h"s (making it deoxy) and the 5" has a triphosphate group (3 inorganic phosphates, becomes monophosphate when linked) Describe b-dna and the higher order structures formed by rna, and the important forces that stabilize these structures. B-dna: righ. t handed (spins counter clockwise as you go up it, looking at it from the side) double helix w. strands running antiparallel, complimentary (for the most part). 2 nm thick, 0. 34 nm between bases, has major and minor groves (bases are not symmetrically oriented relative to the backbone, g-c is closer together), 10 bp per turn of helix.
