Base pair

base pairsbpMbpkbsingle-strandedbase pairingkbpbase-pairbase-pairingbases
A base pair (bp) is a unit consisting of two nucleobases bound to each other by hydrogen bonds.wikipedia
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Nucleobase

basesnucleobasesbase
A base pair (bp) is a unit consisting of two nucleobases bound to each other by hydrogen bonds.
The ability of nucleobases to form base pairs and to stack one upon another leads directly to long-chain helical structures such as ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).

DNA

deoxyribonucleic aciddouble-stranded DNAdsDNA
They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA.
The nitrogenous bases of the two separate polynucleotide strands are bound together, according to base pairing rules (A with T and C with G), with hydrogen bonds to make double-stranded DNA.

DNA polymerase

DNA polymerasespolymeraseDNA
The regular structure and data redundancy provided by the DNA double helix make DNA well suited to the storage of genetic information, while base-pairing between DNA and incoming nucleotides provides the mechanism through which DNA polymerase replicates DNA and RNA polymerase transcribes DNA into RNA.
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from its tightly woven form, in the process breaking the hydrogen bonds between the nucleotide bases.

Transfer RNA

tRNAanticodontRNAs
This is particularly important in RNA molecules (e.g., transfer RNA), where Watson–Crick base pairs (guanine–cytosine and adenine–uracil) permit the formation of short double-stranded helices, and a wide variety of non-Watson–Crick interactions (e.g., G–U or A–A) allow RNAs to fold into a vast range of specific three-dimensional structures. In addition, base-pairing between transfer RNA (tRNA) and messenger RNA (mRNA) forms the basis for the molecular recognition events that result in the nucleotide sequence of mRNA becoming translated into the amino acid sequence of proteins via the genetic code.
The anticodon forms three complementary base pairs with a codon in mRNA during protein biosynthesis.

Nucleic acid sequence

DNA sequencesnucleotide sequencegenetic information
Dictated by specific hydrogen bonding patterns, Watson–Crick base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence. The complementary nature of this based-paired structure provides a redundant copy of the genetic information encoded within each strand of DNA.
The nucleobases are important in base pairing of strands to form higher-level secondary and tertiary structure such as the famed double helix.

Complementarity (molecular biology)

complementarycomplementaritycomplement
The complementary nature of this based-paired structure provides a redundant copy of the genetic information encoded within each strand of DNA.
The degree of complementarity between two nucleic acid strands may vary, from complete complementarity (each nucleotide is across from its opposite) to no complementarity (each nucleotide is not across from its opposite) and determines the stability of the sequences to be together.

Telomere

telomerestelomericAlternative Lengthening of Telomeres
Hence, the number of total base pairs is equal to the number of nucleotides in one of the strands (with the exception of non-coding single-stranded regions of telomeres).
In humans, average telomere length declines from about 11 kilobases at birth to fewer than 4 kilobases in old age, with the average rate of decline being greater in men than in women.

Cytosine

CC'''ytosinecytosines
Dictated by specific hydrogen bonding patterns, Watson–Crick base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence.
In Watson-Crick base pairing, it forms three hydrogen bonds with guanine.

Uracil

Uuracil nucleotidesU'''racil
This is particularly important in RNA molecules (e.g., transfer RNA), where Watson–Crick base pairs (guanine–cytosine and adenine–uracil) permit the formation of short double-stranded helices, and a wide variety of non-Watson–Crick interactions (e.g., G–U or A–A) allow RNAs to fold into a vast range of specific three-dimensional structures.
In RNA, uracil base-pairs with adenine and replaces thymine during DNA transcription.

Human genome

genomehuman DNAhuman geneticist
The haploid human genome (23 chromosomes) is estimated to be about 3.2 billion bases long and to contain 20,000–25,000 distinct protein-coding genes.
Haploid human genomes, which are contained in germ cells (the egg and sperm gamete cells created in the meiosis phase of sexual reproduction before fertilization creates a zygote) consist of three billion DNA base pairs, while diploid genomes (found in somatic cells) have twice the DNA content.

Hydrogen bond

hydrogen bondinghydrogen bondshydrogen-bonding
A base pair (bp) is a unit consisting of two nucleobases bound to each other by hydrogen bonds. Dictated by specific hydrogen bonding patterns, Watson–Crick base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence.
For example, the double helical structure of DNA is due largely to hydrogen bonding between its base pairs (as well as pi stacking interactions), which link one complementary strand to the other and enable replication.

RNA

ribonucleic aciddsRNAdouble-stranded RNA
They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA. The GU pairing, with two hydrogen bonds, does occur fairly often in RNA (see wobble base pair).
This antisense-based process involves steps that first process the RNA so that it can base-pair with a region of its target mRNAs.

Biomass (ecology)

biomassmassmarine biomass
In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).
The total number of DNA base pairs on Earth, as a possible approximation of global biodiversity, is estimated at (5.3±3.6), and weighs 50 billion tonnes.

Protein

proteinsproteinaceousstructural proteins
In addition, base-pairing between transfer RNA (tRNA) and messenger RNA (mRNA) forms the basis for the molecular recognition events that result in the nucleotide sequence of mRNA becoming translated into the amino acid sequence of proteins via the genetic code.
The mRNA is loaded onto the ribosome and is read three nucleotides at a time by matching each codon to its base pairing anticodon located on a transfer RNA molecule, which carries the amino acid corresponding to the codon it recognizes.

Chromosome

chromosomeschromosomalChromosomal number
The haploid human genome (23 chromosomes) is estimated to be about 3.2 billion bases long and to contain 20,000–25,000 distinct protein-coding genes.
The chromosomes of most bacteria, which some authors prefer to call genophores, can range in size from only 130,000 base pairs in the endosymbiotic bacteria Candidatus Hodgkinia cicadicola and Candidatus Tremblaya princeps, to more than 14,000,000 base pairs in the soil-dwelling bacterium Sorangium cellulosum.

Gene

genesnumber of genesgene sequence
The size of an individual gene or an organism's entire genome is often measured in base pairs because DNA is usually double-stranded.
Two chains of DNA twist around each other to form a DNA double helix with the phosphate-sugar backbone spiralling around the outside, and the bases pointing inwards with adenine base pairing to thymine and guanine to cytosine.

Wobble base pair

wobblewobble hypothesiswobble base
The GU pairing, with two hydrogen bonds, does occur fairly often in RNA (see wobble base pair).
A wobble base pair is a pairing between two nucleotides in RNA molecules that does not follow Watson-Crick base pair rules.

Nucleic acid structure

RNA structureDNA structureDNA topology
This is particularly important in RNA molecules (e.g., transfer RNA), where Watson–Crick base pairs (guanine–cytosine and adenine–uracil) permit the formation of short double-stranded helices, and a wide variety of non-Watson–Crick interactions (e.g., G–U or A–A) allow RNAs to fold into a vast range of specific three-dimensional structures.
The nucleotides on one strand base pairs with the nucleotide on the other strand.

Transcription (biology)

transcriptiontranscribedtranscriptional
On the converse, regions of a genome that need to separate frequently — for example, the promoter regions for often-transcribed genes — are comparatively GC-poor (for example, see TATA box). Chemical analogs of nucleotides can take the place of proper nucleotides and establish non-canonical base-pairing, leading to errors (mostly point mutations) in DNA replication and DNA transcription.
Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language.

TATA box

TATATATA-boxmammalian C-type LTR TATA box
On the converse, regions of a genome that need to separate frequently — for example, the promoter regions for often-transcribed genes — are comparatively GC-poor (for example, see TATA box).
It was termed the "TATA box" as it contains a consensus sequence characterized by repeating T and A base pairs.

GC-content

GC contentguanine and cytosine contentG+C content
DNA with high GC-content is more stable than DNA with low GC-content.
Quantitatively, each GC base pair is held together by three hydrogen bonds, while AT and AU base pairs are held together by two hydrogen bonds.

Directionality (molecular biology)

533' end
By convention, the top strand is written from the 5' end to the 3' end; thus, the bottom strand is written 3' to 5'.
In a DNA double helix, the strands run in opposite directions to permit base pairing between them, which is essential for replication or transcription of the encoded information.

DNA replication

replicationreplication forklagging strand
Chemical analogs of nucleotides can take the place of proper nucleotides and establish non-canonical base-pairing, leading to errors (mostly point mutations) in DNA replication and DNA transcription.
Nucleobases are matched between strands through hydrogen bonds to form base pairs.

Primer (molecular biology)

primerprimersRNA primer
GC content and melting temperature must also be taken into account when designing primers for PCR reactions.
In solution, the primer spontaneously hybridizes with the template through Watson-Crick base pairing before being extended by DNA polymerase.

Polymerase chain reaction

PCRPCR amplificationpolymerase chain reaction (PCR)
GC content and melting temperature must also be taken into account when designing primers for PCR reactions.
Most PCR methods amplify DNA fragments of between 0.1 and 10 kilo base pairs (kbp) in length, although some techniques allow for amplification of fragments up to 40 kbp.