Question

You are given two solutions containing different purified DNAs. One is from the bacterium P. aeruginosa and has a G + C composition of 68%, whereas the other is from a mammal and has G + C composition of 42%. You measure the UV absorbance of each solution as a function of increasing the temperature. Which solution will yield the higher Tm value and why?

Answer 1

Answer:

The solution of P. aeruginosa will yield higher Tm value.

Explanation:

The solution of P.aeruginosa contain 68% G+C composition as a result the DNA of P.aeruginosa is more stable than the DNA of mammal contain only 42% G+C composition.G+C composition is most stable because guanine is linked to cytosine by 3 hydrogen bonds whereas adenine linked to thymine by 2 hydrogen bonds.

   As  P.aeruginosa DNA is more stable than mammalian DNA,as a result the DNA solution of P.aeruginosa will yield high Tm(melting temperature) value than that of mammalian DNA.