Unformatted text preview: . • Strong absorbance at 260 nm is used for quantitative determination of
• It allows measurement of nucleic acid concentrations at the microgram/
mL level by measurement of light absorption. The Nature of Nucleic Acids
How polynucleoDdes are actually formed. Formation of a
polynucleotide by a
reaction. Each monomer is presented as an NTP to be added to the chain. Cleavage of the NTP provides the free energy that makes the reacDon thermodynamically favorable. The enzymes catalyzing such reacDons are called polymerases. Primary Structure
We can abbreviate a small DNA molecule as follows: This notation shows:
1. The sequence of nucleotides, by their letter abbreviations (A, C, G, T).
2. All phosphodiester links are between hydroxyls and phosphates.
3. This particular molecule has a phosphate group at its 5’ end and an
unreacted hydroxyl at its 3’ end.
4. It also tells us it is a DNA sequence, not RNA because it has T, not U. More simply: 5’
• Primary Structure of Nucleic Acids
• Secondary and Tertiary Structure of
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