Predicting the melting temperature of DNA

The melting temperature of a DNA molecule can be determined by differential scanning calorimetry In the laboratory 1.1). The following data were obtained in 0.010 M Na3P04(aq) for a series of DNA molecules with varying base pair composition, with/the fraction of C-G base pairs  

Estimate the melting temperature of a DNA molecule containing 40.0 per cent C-G base pairs. 

16 A protein unfolds as the temperature of the sample increases. The sharp step in the plot of fraction of unfolded protein against temperature indicates that the transition is cooperative. The melting temperature, T , is the temperature at which the fraction of unfolded polymer is 0.5. 

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