Final answer:
One nucleotide is distinguished from another in nucleic acids by the nitrogenous base it contains. DNA and RNA have different sugars, deoxyribose, and ribose, respectively, but it is the unique nitrogenous bases that give each nucleotide its identity. The correct option is c. By the nitrogenous base, it contains.
Step-by-step explanation:
The way to distinguish one nucleotide from another in nucleic acids is c. By the nitrogenous base it contains. Each nucleotide is composed of three parts: a five-carbon sugar (pentose), a phosphate group, and a nitrogenous base. The sugar can be either deoxyribose, found in DNA, or ribose, found in RNA. Although the sugar and phosphate groups are the same within the nucleotides of a nucleic acid, the nitrogenous bases are what make each nucleotide unique.
There are four nitrogenous bases in DNA: adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, the bases are the same except that uracil (U) replaces thymine.
Each nucleotide in DNA is named for the nitrogenous base it carries. The purines, adenine, and guanine, have a double-ring structure, while the pyrimidines, cytosine, and thymine (or uracil in RNA), have a single-ring structure. The sequence of these bases along the nucleic acid strand holds genetic information, with DNA serving as the blueprint for genetic inheritance and RNA playing a crucial role in the synthesis of proteins.