Question 17

Hydrogen bonds hold the strands of DNA together.

Hydrogen bonds are the specific type of bond that holds the nucleotide bases of DNA strands together, facilitating the double helix structure essential for DNA stability and function.

A) Hydrogen

Hydrogen bonds are weak attractions between the hydrogen atom of one nucleotide base and an electronegative atom of another base, specifically between adenine and thymine (A-T) or guanine and cytosine (G-C). These bonds are crucial for maintaining the structure of the DNA double helix, allowing the strands to separate during replication and transcription without breaking the overall integrity of the molecule.

B) Sodium chloride

Sodium chloride is an ionic compound and does not play a role in the bonding of DNA strands. While it can influence the stability of DNA in a solution, it does not contribute to the structural integrity of the DNA double helix through direct bonding.

C) Copper

Copper is a metal and is not involved in the bonding between nucleotide bases in DNA. It does not participate in any form of bond that would hold the strands of DNA together, making this option incorrect.

D) Potassium bromide

Potassium bromide is also an ionic compound and similarly does not contribute to the bonding between DNA strands. Like sodium chloride, while it may affect DNA in a solution, it does not form the necessary connections between nucleotide bases.

Conclusion

Hydrogen bonds are essential for the structural integrity of DNA, providing the necessary connections between base pairs that enable the formation of the double helix. All other options fail to represent any relevant bonding mechanism within the context of DNA structure, making hydrogen bonds the definitive correct answer.