nitrogenous base

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base

 [bās]
1. the lowest part or foundation of anything. See also basis.
2. the main ingredient of a compound.
3. the nonacid part of a salt; a substance that combines with acids to form salts. In the chemical processes of the body, bases are essential to the maintenance of a normal acid-base balance. Excessive concentration of bases in the body fluids leads to alkalosis.
4. a unit of a removable dental prosthesis.
5. in genetics, a nucleotide, particularly one in a nucleic acid sequence.
intermediary base the layer of cement between a dental restoration and the tooth structure, acting as an insulator and protective barrier.
nitrogenous base an aromatic, nitrogen-containing molecule that serves as a proton acceptor, e.g., purine or pyrimidine.
ointment base a vehicle for the medicinal substances carried in an ointment.
purine b's a group of compounds of which purine is the base, including uric acid, adenine, xanthine, and theobromine.
Bases. A, Purine and some substituted purine bases occurring in nucleic acids. B, Pyrimidine and some substituted pyrimidine bases occurring in nucleic acids. From Dorland's, 2000.
pyrimidine b's a group of chemical compounds of which pyrimidine is the base, including uracil, thymine, and cytosine, which are common constituents of nucleic acids.

nitrogenous base

n.
Variant of nitrogen base.

nitrogenous base

A molecule containing nitrogen with the chemical properties of a base.

Nitrogenous bases—DNA
• Purine bases—Adenine (A), guanine (G).
• Pyrimidine bases—Cytosine (C), thymine (T).

Nitrogenous bases—RNA 
• Purine bases—Adenine (A), guanine (G).
• Pyrimidine bases—Cytosine (C), uracil (U).

base

1. the lowest part or foundation of anything. See also basis.
2. the main ingredient of a compound.
3. a molecule or ion with a tendency to take up a proton according to Bronsted and Lowry theory; a substance that combines with acids to form salts. In the chemical processes of the body, bases are essential to the maintenance of a normal acid-base balance. Excessive concentration of bases in the body fluids leads to alkalosis. See also basal.
4. the primary entity against which all other entities are compared.
5. the non-sugar components of nucleotides in DNA and RNA.

acid-base pairs
the two molecules forming the matching acid and conjugate base.
base composition
refers to the relative components of a nucleic acid.
conjugate base
the anion or uncharged molecule of an acid once it has given up its proton, e.g. Cl is the conjugate base of the acid, HCl.
base deficit
see base excess (below).
base excess
the amount of acid or base required to titrate a sample of whole arterial blood to the normal pH of 7.4. The base excess is determined mathematically by calculations that include measurement of the blood Pco2 and pH and take into account the hemoglobin level. It is negative (base deficit) in acidosis and positive in alkalosis.
heart base
the wide dorsal part of the heart carrying the atria and the large blood vessels and the attachment to the pericardial sac.
horn base
the widest part of the horn, at its attachment to the skin. In the adult horned animal the horn is hollow at this point, encloses the horn process of the frontal bone and merges with the skin. This is covered with a thin layer of horn similar to the periople of the hoof, called the epiceras.
narrow base
a mandible which is narrow relative to the maxilla; often causes the lower canine teeth to strike the hard palate. See also anisognathism.
nitrogenous base
an aromatic, nitrogen-containing molecule that serves as a proton acceptor, e.g. purine or pyrimidine.
omasal base
faces cranially and to the left where it is attached to the reticulum and the abomasum at the reticulo-omasal and omasoabomasal orifices.
base pair
two hydrogen bonded nucleotides in a DNA or RNA molecule.
purine b's
a group of compounds of which purine is the base, including uric acid, adenine, guanine, xanthine and theobromine.
pyrimidine b's
a group of chemical compounds of which pyrimidine is the base, including uracil, thymine and cytosine, which are common constituents of nucleic acids.
stapedal base
the footplate of the stapes in the middle ear from which the two legs originate. The stapes lies horizontally with the base facing medially and attached to the vestibular window by the annular ligament.
References in periodicals archive ?
Classical bioisosterism can exists among pyrimidine nitrogenous bases (single ring structure) like cytosine and uracil.
Bioisosteric replacement of carbonyl oxygen in guanine (pyridine-imidazole ring system), a nitrogenous base by S gives 6-thioguanine (potent anti-cancer antimetabolite).
The SOP model is used as an analytic device to provide a theoretical description for the structure of a nucleotide (the configuration of a nitrogenous base with a sugar and a phosphate group) that forms strands of DNA (chromosomes).
What is astonishing is that there are only four nitrogenous bases found in all of the entire strand of DNA: adenine (A) linked to thymine (T), or cytosine (c) linked to guanine (G).
Unlike DNA, which is double stranded and consists of the four nitrogenous bases A, T, G and C, RNA is single stranded and has the nitrogenous base uracil ("U") instead of thymine ("T").
Each triplet of nitrogenous bases, known as a codon, on the messenger RNA represents a code for an amino acid.
If a normal sequence of nitrogenous bases is CAT ACT TAG GAG, then a mutation in the "TAG" sequence can involve a substitution (TTG instead of TAG), deletion (TG instead of TAG) or insertion (TAAG instead of TAG).