I just need help with b. I'm unfamiliar with plotting in excel or mathlab. I'll need two graphs, one for AT and another for GC. Feel free to correct me but here are the equations I came up with:

A=0.711 F_D + 1.003(1-F_D) for AT

A= 0.780F_D + 0.975(1-F_D) for GC

The FD is the fraction in the double-stranded form.

3. When self-complementary strands of DNA are mixed, they form a double-stranded DNA at low temperatures but dissociate to single strands as the tempcrature is raised: TOC) A (oligoA-T) TOC) A (oligoG-C) DR2S 500 0.780 This can be observed by an increase in the 0.720 10 55 0.785 absorbance of the solutions at 260 nm (The 0.732 15 0.812 double helix is said to show 0.836 0.740 65 "hypochromicity" at this wavelength) 0.767 70 0.862 Data for two experiments are given on the 30 0.801 75 0.880 right. In one case, short DNA strands made 35 0.846 80 0.896 of A and T nucleotides (oligoA-T) were 40 0.874 85 mixed, whereas, in the other case, the same 45 0.891 0.948 length strands and concentrations of 50 0.903 95 0.975 oligomers of G and C (oligoG-C) G were 55 1.003 mixed. a. Assume that the molecules are duplexes (D) at the lowest temperatures for which data are given and single strands (S) at the highest temperatures. Calculate the fraction present as duplex at each temperature. b. Plot out the fraction ofD as a function of temperature in Excel. Use this to determine the melting temperature of each oligomer (remember, that is the temperature at which the fraction of strands in in the D form and S form are equal). c. What do these results tell you about the relative strength of A-T and G-C pair interactions