What is the main role of nucleotides in DNA?

Nucleotides play a crucial role in the structure and function of DNA as they serve as the fundamental building blocks of nucleic acids. Each nucleotide consists of three components: a phosphate group, a sugar molecule (deoxyribose in the case of DNA), and a nitrogenous base (adenine, thymine, cytosine, or guanine). These nucleotides link together through phosphodiester bonds to form long chains, creating the backbone of the DNA molecule.

The sequence of these nitrogenous bases along the sugar-phosphate backbone encodes genetic information, which is essential for the inheritance of traits and for guiding the synthesis of proteins. Thus, nucleotides are not only structural components but also play a pivotal role in storing and transmitting genetic information within biological systems.

Other roles highlighted in the options, such as energy supply and protein production, involve different molecules. For instance, ATP is a nucleotide that primarily provides energy for cellular processes, while proteins are synthesized based on the instructions provided by the DNA, not by the nucleotides themselves.