In a plot of temperature versus absorbance of light at 260 nm by DNA, on what does Tm depend?
A) Equilibrium between denatured and renatured species
B) Kcat of denaturation
C) Length of DNA
D) Molecular weight of DNA
E) Percent of guanine and adenine bases

Question

Quizplus · Accepted Answer

Tm (melting temperature) is the temperature at which half of the DNA strands have denatured. This temperature depends on the percent of guanine and adenine bases, as these bases form two hydrogen bonds with each other, making them more stable than cytosine and thymine, which form only three hydrogen bonds. Therefore, a higher percentage of guanine and adenine bases will result in a higher Tm.

In a Plot of Temperature Versus Absorbance of Light at 260