Question

At specific high temperatures (melting temperatures), DNA is denatured depending on its __________. Triple hydrogen bond is more difficult to disrupt than a double.

A) Nucleotide composition
B) GC content
C) Sequence complexity
D) Sugar-phosphate backbone

Answer 1

DNA denatures at high temperatures due to the disruption of hydrogen bonds between bases, and the ease of denaturation depends on the GC content. Higher GC content makes DNA more resistant to denaturation, as G-C base pairs have three hydrogen bonds, compared to the two hydrogen bonds of A-T base pairs.

Step-by-step explanation:

At specific high temperatures (melting temperatures), DNA is denatured depending on its GC content. The process of denaturation involves the unfolding of the double helical structure of DNA due to the disruption of hydrogen bonds between the bases. Certain factors such as pH and temperature (above 80 to 90 degrees Celsius) contribute to the denaturation of DNA, whereby the two strands dissociate from each other.

GC content plays a pivotal role in the stability of DNA's double helix structure because guanine and cytosine (G and C) form three hydrogen bonds, in comparison to adenine and thymine (A and T), which only form two. Therefore, DNA with a higher GC content requires a higher temperature to disrupt these additional hydrogen bonds, making it more difficult to denature than DNA with lower GC content.