nukleotydu

Nucleotides are the basic units of nucleic acids and play essential roles in metabolism. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. The sugar is ribose in RNA and deoxyribose in DNA; the bases include purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil in RNA).

Structurally, the base attaches to the 1' carbon of the sugar, while the phosphate group attaches to the 5' carbon. Nucleotides form nucleic acids through phosphodiester bonds, linking the 5' phosphate of one nucleotide to the 3' carbon of the next. This creates the backbone of DNA and RNA and determines directionality in polymerization.

Functions extend beyond genetic information. DNA and RNA nucleotides serve as monomers that encode, store, and transmit hereditary data. Energy carriers such as ATP and GTP power cellular processes; signaling molecules like cyclic AMP regulate various pathways. Coenzymes such as NAD+, FAD, and CoA participate in redox reactions and metabolic transfers, while other nucleotide derivatives act as secondary messengers or regulators.

Nucleotide metabolism includes de novo synthesis and salvage pathways, allowing cells to produce or reclaim nucleotides as needed. These processes depend on vitamins, minerals, and cellular energy, and are tightly controlled to balance synthesis, utilization, and degradation.

In summary, nucleotides are versatile small molecules central to genetics, energy transfer, signaling, and metabolism, forming the cornerstone of cellular function and heredity.