Final answer:
AT Rich DNA has a lower melting temperature compared to GC rich DNA because GC pairs have stronger hydrogen bonding due to three hydrogen bonds as opposed to the two hydrogen bonds in AT pairs.
Step-by-step explanation:
AT Rich DNA melts at a significantly lower temperature than GC rich DNA. DNA's two strands are held together by hydrogen bonds formed through base pairing. Adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C), with GC pairs involving three hydrogen bonds compared to the two bonds of AT pairs.
Hence, more energy (in the form of heat) is needed to break these hydrogen bonds in GC-rich regions, resulting in higher melting temperatures. The process of DNA separation, called denaturation, occurs at the melting temperature (Tm), revealing how tightly the two strands bind. GC-rich regions, having more hydrogen bonds, have a higher Tm, making them more difficult to denature compared to AT-rich regions.