Final answer:
GC-rich DNA has a higher melting temperature than AT-rich DNA due to the presence of three hydrogen bonds between G and C, compared to two bonds between A and T, providing greater stability to the DNA helix.
Step-by-step explanation:
GC-rich DNA melts at a higher temperature than AT-rich DNA. The melting temperature, or Tm, reflects the stability of the double helix and is dependent on the base pairing between the DNA strands. Guanine (G) and Cytosine (C) form three hydrogen bonds between them, while Adenine (A) and Thymine (T) only form two. Therefore, the more GC content a DNA molecule has, the more hydrogen bonds are present, which increases the melting temperature. DNA denaturation is a process where the DNA double helix melts, or separates into two single strands, at high temperatures or extreme pH levels. This property is important to understand in procedures like PCR, where DNA strands are separated by heating to temperatures such as 94°C.