What role do nucleotides play in DNA?

Nucleotides are indeed the fundamental building blocks of DNA. Each nucleotide consists of three components: a phosphate group, a five-carbon sugar (deoxyribose in the case of DNA), and a nitrogenous base (adenine, thymine, cytosine, or guanine). The sequence of these nucleotides encodes genetic information, and they link together through phosphodiester bonds to form the long chains that make up the DNA molecule. This structure is crucial for DNA's ability to store and transmit genetic information during processes like replication and transcription.

The other options describe roles that do not apply to nucleotides in the context of DNA. While nucleotides can serve as energy carriers in the form of ATP, this does not pertain to their role within DNA. Additionally, nucleotides do not function as enzymes; enzymes are typically proteins that catalyze biochemical reactions, not nucleotides. Lastly, nucleotides are not structural components of the cell membrane; that function is primarily served by lipids and proteins. Hence, understanding the role of nucleotides as the building blocks of DNA is essential for grasping fundamental concepts of genetics and molecular biology.