DNA is stable because hydrogen bonds are formed between
The correct answer and explanation is:
DNA is stable because hydrogen bonds are formed between complementary nitrogenous bases, specifically adenine (A) with thymine (T), and guanine (G) with cytosine (C). These base pairs are connected by two hydrogen bonds between adenine and thymine and by three hydrogen bonds between guanine and cytosine. This arrangement is crucial for the overall stability and functionality of DNA. The complementary base pairing ensures that the DNA molecule maintains its helical structure and that the genetic information encoded within it can be accurately copied and transmitted during processes such as replication.
The hydrogen bonds themselves are relatively weak individually, which allows for the necessary separation of the DNA strands during processes like replication and transcription. However, when these hydrogen bonds are collectively present across the entire molecule, they contribute significantly to the overall stability and integrity of the DNA double helix. This balance between stability and the ability to uncoil when needed is key to the DNA’s function in storing genetic information.
Additionally, the overall structure of DNA, including the sugar-phosphate backbone and the hydrophobic interactions between the stacked base pairs, further strengthens its stability. The hydrophobic bases are tucked inside the helix, protected from the aqueous environment, while the hydrophilic phosphate groups form the outer backbone, interacting with the water in the cell. This combination of hydrogen bonding between base pairs, hydrophobic interactions, and the sugar-phosphate backbone contributes to DNA’s remarkable stability, ensuring that genetic information is preserved over time.
Thus, the hydrogen bonds between complementary nitrogenous bases play a vital role in DNA’s stability by holding the two strands together, allowing for both preservation and transmission of genetic information.