Recall that two hydrogen bonds bind A and T, but three hydrogen bonds bind G and C.The stability of DNA is affected by the number of hydrogen bonds, with more bonds promoting more stability.Double-stranded DNA molecules that have greater stability require more heat to be broken into single strands.Which double-stranded DNA molecule would likely require the lowest temperature in PCR?
A) A molecule with 16 percent A
B) A molecule with 23 percent G
C) A molecule with 30 percent C
D) A molecule with 35 percent T
E) A molecule with 38 percent A

Question

Quizplus · Accepted Answer

The molecule with a higher percentage of T will have more hydrogen bonds, as they form two hydrogen bonds with A. Therefore, this molecule will be more stable and require a higher temperature to melt, making it the most suited for PCR.

Recall That Two Hydrogen Bonds Bind a and T, but Three