Purine (1) is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. Purines make up one of the two groups of nitrogenous bases. Pyrimidines make up the other group.
purine
purine base; basic compounds related in structure to uric acid; examples include adenine and guanine, which are bases and constituents of nucleic acids ...
Purine: A nitrogen- containing, double ring compound that occurs in nucleic acids. In DNA molecules, the purines are adenine and guanine.
Purine analogs
These are relatives of the purines used in DNA synthesis. Because they interfere with DNA synthesis, they interfere with the rapid cell proliferation needed for immune responses.
purine One of the groups of nitrogenous bases that are part of a nucleotide. Purines are adenine and guanine, and are double-ring structures. PICTURE ...
purine
[Gk. purinos, fiery, sparkling]
A nitrogenous base, such as adenine or guanine, with a characteristic two-ring structure; one of the components of nucleic acids.
pyramid, ecological ...
Purine A nitrogenous base that includes a pyrimidine ring fused with a five-membered imidazole ring; the purine derivatives adenine and guanine are found in nucleotides and nucleic acids.
[edit] Purine ribonucleotides
By using a variety of isotopically labelled compounds it was demonstrated that the sources of the atoms in purines are as follows:
The biosynthetic origins of purine ring atoms ...
PURINE BASES - Adenine (A) or Guanine (G) (see NUCLEOTIDE).
PULSED-FIELD GEL ELECTROPHORESIS (PFGE) - Separation of large (>50 kb) pieces of DNA, including complete chromosomes and genomes, ...
purine A nitrogen-containing organic compound that contributes to the structure of a DNA or RNA nucleotide; uric acid is also derived from purines.
push factors (in urbanization)Conditions that force people out of the country and into the city.
7 H-Purine
Nitrogenous base
A nitrogen-containing molecule having the chemical properties of a base. See purine and pyrimidine.
7 H-Purine
Pyrimidine
A nitrogen-containing, single-ring, basic compound (cf. nitrogenous base) that occurs in nucleic acids. The pyrimidines in DNA are cytosine and thymine. The pyrimidines in RNA are cytosine and uracil.
Adenine (A) ...
Adenin is a purine base (nitrogenous base) and constituent of nulceotides and as such one member of the base pair A-T (adenine-thymine) in DNA and A-U (adenine-uracil) in RNA.
Two nitrogenous (purine or pyrimidine) bases (adenine and thymine or guanine and cytosine) held together by weak hydrogen bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between base pairs.
A purine or pyrimidine base that differs slightly in structure from the normal bases found in DNA or RNA. Some analogs may be incorporated into nucleic acids in place of the normal base, often resulting in a base substitution mutation.
The purines (adenine and guanine) and pyrimidines (thymine, cytosine, and uracil) that comprise DNA and RNA molecules. Nodule. The enlargement or swelling on roots of nitrogen- fixing plants. The nodules contain symbiotic nitrogen- fixing bacteria.
base pair a pair of hydrogen-bonded nitrogenous bases (one purine and one pyrimidine) that join the component strands of the DNA double helix.
The minima of the Purine Excess plots correlate with the origins of replication for seven bacterial genomes (Escherichia coli, Bacillus subtilis, Mycoplasma pneumoniae, Mycoplasma genitalium, Helicobacter pylori, Haemophilus influenzae, ...
Transitions (changes from a purine - A or G - to the other purine, or a pyrimidine - C or T - to the other pyrimidine) are more likely than transversions (changes from a purine to a pyrimidine or vice-versa).
Depurination of DNA results in the loss of a purine from the DNA backbone and DNA strand breakage. Such DNA lesions are often the result of ionizing radiation, free radicals, or alkylating reagents that destabilize the N-glycosidic bond.
Notice that a double-ringed purine is always bonded to a single ring pyrimidine. Purines are Adenine (A) and Guanine (G).
- A base-pair substitution mutation resulting in the replacement of one purine by another purine or of one pyrimidine by another pyrimidine
Translation
- The process of biosynthesis of a polypeptide chain using genetic instructions from the mRNA ...
complementary base pairs - base-pairing between a larger purine base (adenine or guanine) and a smaller pyrimidine base (cytosine or thymine) while DNA is in its double-helix. (A/T, G/C) ...
Chargaff's rules showed that A = T and G = C, so there was complementary base pairing of a purine with a pyrimidine, giving the correct width for the helix.
The paired bases can occur in any order, giving an overwhelming diversity of sequences.
Transition A mutation which has changed one purine (A, G) into the other, or one pyrimidine (C, T) into the other. See transversion.
Translation The process of copying a mRNA into a polypeptide chain mediated by the ribosomes.
Nitrogenous bases. The purines (adenine and guanine) and pyrimidines (thymine, cytosine, and uracil) that comprise DNA and RNA molecules.
The basic building blocks of nucleic acids. They are made up of a nitrogen-containing purine or pyrimidine base linked to a sugar (ribose or deoxyribose) and a phosphate group.
transition A type of point mutation in which one purine or pyrimidine is replaced by another base of the same type. Examples: A-G and C-T.
Nucleotides contain a (purine or pyrimidine) base attached to a sugar (ribose or deoxyribose) and phosphate (PO4 =). The four bases in DNA code for all our genetic information and therefore for all the proteins we make.
For example, the (fictitious) transcription factor ZQ1 usually binds to the sequences AAAGTT, AAGGTT or AAGATT. The consensus sequence for that factor is said to be AARRTT (where R is any purine, i.e. A or G).
Nucleoside In molecular biology; a molecule composed of a sugar (2' deoxyribose in DNA; ribose in RNA) which is linked to a purine (adenine or guanine) or a pyrimidine (thymine (DNA), cytidine or uridine (RNA)).
 See also: DNA, Base, Molecule, Nucleotide, Pyrimidine
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