In a double helix, the two strands are oriented in opposite directions, which permits base pairing and complementarity between the base-pairs, all which is essential for replicating or transcribing the encoded information found in DNA. In any one strand, the chemical orientation ( directionality) of the chain-joins runs from the 5'-end to the 3'-end ( read: 5 prime-end to 3 prime-end)-referring to the five carbon sites on sugar molecules in adjacent nucleotides. These chain-joins of sugar and phosphate molecules create a 'backbone' strand for a single- or double helix. Individual phosphate molecules repetitively connect the sugar-ring molecules in two adjacent nucleotide monomers, thereby connecting the nucleotide monomers of a nucleic acid end-to-end into a long chain. In nucleic acids, nucleotides contain either a purine or a pyrimidine base-i.e., the nucleobase molecule, also known as a nitrogenous base-and are termed ribonucleotides if the sugar is ribose, or deoxyribonucleotides if the sugar is deoxyribose. With all three joined, a nucleotide is also termed a 'nucleo side monophosphate', 'nucleoside diphosphate' or 'nucleoside triphosphate', depending on how many phosphates make up the phosphate group. The individual nucleotide monomers are chain-joined at their sugar and phosphate molecules, forming two 'backbones' (a double helix) of nucleic acid, shown at upper left.ДЄ nucleo tide is composed of three distinctive chemical sub-units: a five-carbon sugar molecule, a nucleobase-the two of which together are called a nucleo side-and one phosphate group. At the upper right, four nucleotides form two base-pairs: thymine and adenine (connected by double hydrogen bonds) and guanine and cytosine (connected by triple hydrogen bonds). Showing the arrangement of nucleotides within the structure of nucleic acids: At lower left, a monophosphate nucleotide its nitrogenous base represents one side of a base-pair. In experimental biochemistry, nucleotides can be radiolabeled using radionuclides to yield radionucleotides. In addition, nucleotides participate in cell signaling ( cyclic guanosine monophosphate or cGMP and cyclic adenosine monophosphate or cAMP), and are incorporated into important cofactors of enzymatic reactions (e.g. They provide chemical energy-in the form of the nucleoside triphosphates, adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP) and uridine triphosphate (UTP)-throughout the cell for the many cellular functions that demand energy, including: amino acid, protein and cell membrane synthesis, moving the cell and cell parts (both internally and intercellularly), cell division, etc. Nucleotides also play a central role in metabolism at a fundamental, cellular level. The four nucleobases in DNA are guanine, adenine, cytosine and thymine in RNA, uracil is used in place of thymine. Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar ( ribose or deoxyribose), and a phosphate group consisting of one to three phosphates.

Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver. They serve as monomeric units of the nucleic acid polymers вЂ“ deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are organic molecules consisting of a nucleoside and a phosphate. The deoxyribose sugar joined only to the nitrogenous base forms a Deoxyribonucleoside called deoxyadenosine, whereas the whole structure along with the phosphate group is a nucleotide, a constituent of DNA with the name deoxyadenosine monophosphate. This nucleotide contains the five-carbon sugar deoxyribose (at center), a nucleobase called adenine (upper right), and one phosphate group (left).

N nucelotide sequence snapgene viewer