The melting profile for a DNA is found to differ in two different salt solutions. In 0.001 M NaCl, T_m = 55 ° C, and in 0.01 M NaCl, T_m = 65 ° C. The fundamental reason for this change is A) higher salt concentration increases the electrostatic repulsions between phosphates B) the base stacking is more effective in high salt C) hydrogen bonding between complementary bases in enhanced at high salt D) higher salt concentration decreases the electrostatic repulsions between phosphates

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Quizplus · Accepted Answer

Higher salt concentration decreases the electrostatic repulsions between the negatively charged phosphate groups in the DNA backbone. This stabilization allows the DNA helix to remain intact at higher temperatures, hence the increase in melting temperature with higher salt concentration.

The Melting Profile for a DNA Is Found to Differ