The A-T content for several DNA strands is reported below.Which strand would have the highest T_m? A) 40% A-T B) 50% A-T C) 60% A-T D) 70% A-T

Question

Quizplus · Accepted Answer

The melting temperature (T_m) of DNA is higher when the G-C content is higher because G-C pairs have three hydrogen bonds compared to two in A-T pairs. Therefore, the strand with the lowest A-T content (40% A-T) has the highest G-C content and thus the highest T_m.

The A-T Content for Several DNA Strands Is Reported Below