Final answer:
A complete nucleotide comprises a pentose sugar, a nitrogen-containing base, and one or more phosphate groups. The structure is integral to forming the backbone of DNA and RNA, as well as functioning in energy transfer as ATP.
Step-by-step explanation:
A complete nucleotide consists of three fundamental components:
- A pentose sugar, which is a five-carbon sugar. It can be ribose in the case of RNA or deoxyribose in DNA, where the deoxyribose lacks an oxygen atom at the 2' position.
- A nitrogen-containing base which can be a purine—adenine (A) or guanine (G)—or a pyrimidine—cytosine (C), thymine (T), or uracil (U). Uracil is only found in RNA.
- One or more phosphate groups, which are linked to the 5' carbon of the pentose sugar.
When assembled into nucleic acids, the phosphate of one nucleotide connects to the 3' hydroxyl group of the next nucleotide's sugar, forming a backbone of alternating phosphates and sugars with the bases as side groups.
In addition to forming the backbone of DNA and RNA, nucleotides like adenosine triphosphate (ATP) serve as an energy currency within the cell.