Which one of the following bonds links two nucleotides in a nucleic acid?
**Core Concept**
A nucleic acid is a biopolymer composed of nucleotides linked together through specific chemical bonds. This unique structure allows for the storage and transmission of genetic information.
**Why the Correct Answer is Right**
The correct answer is the phosphodiester bond, which is formed between the phosphate group of one nucleotide and the sugar molecule of another. This bond is crucial for the stability and integrity of the nucleic acid chain. The phosphodiester bond is a result of the condensation reaction between the phosphate group and the hydroxyl group of the sugar, releasing a molecule of water in the process. This bond is responsible for the double helix structure of DNA and the single-stranded structure of RNA.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a hydrogen bond is a weak electrostatic attraction between a hydrogen atom and an electronegative atom, such as oxygen or nitrogen. While hydrogen bonds do play a crucial role in the structure of nucleic acids, they do not form the covalent bond between nucleotides.
**Option B:** This option is incorrect because a peptide bond is a covalent bond formed between two amino acids during protein synthesis. It is not relevant to the structure of nucleic acids.
**Option C:** This option is incorrect because a disulfide bond is a covalent bond formed between two sulfur atoms, typically between cysteine residues in proteins. It is not relevant to the structure of nucleic acids.
**Clinical Pearl / High-Yield Fact**
The phosphodiester bond is a high-yield concept in biochemistry and molecular biology, and students should be able to identify it as the correct answer in this question. The ability to recognize this bond is crucial for understanding the structure and function of nucleic acids.
**Correct Answer:** . Phosphodiester bond