Both DNA and also RNA are well-known as nucleic acids. They have actually been offered this name for the basic reason the they are made up of structures dubbed nucleotides. Those nucleotides, themselves comprising a variety of components, bond with each other to form the double-helix very first discovered by the researchers James Watson and Francis Crick in 1956. This exploration won the two scientists the Nobel Prize. Because that now, as soon as we talk about nucleic acids you should assume we are mentioning DNA quite than RNA, uneven otherwise specified.

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Nucleotides

A nucleotide is composed of 3 things: A nitrogenous base, which have the right to be one of two people adenine, guanine, cytosine, or thymine (in the case of RNA, thymine is changed by uracil).A five-carbon sugar, referred to as deoxyribose since it is lacking an oxygen group on one of its carbons.One or much more phosphate groups. The nitrogen bases space pyrimidine in framework and form a bond between their 1" nitrogen and also the 1" -OH group of the deoxyribose. This kind of shortcut is dubbed a glycosidic bond. The phosphate group develops a bond with the deoxyribose sugar through an ester bond between one the its negatively charged oxygen groups and the 5" -OH that the sugar ().

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Figure %: A Nucleotide

main point Acids

Nucleotides sign up with together with phosphodiester linkages between the 5" and also 3" carbon atoms to kind nucleic acids. The 3" -OH the the street group forms a bond with among the negatively fee oxygens of the phosphate group attached to the 5" carbon of one more sugar. When plenty of of this nucleotide subunits combine, the an outcome is the large single-stranded polynucleotide or nucleic acid, DNA ()

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Figure %: The Nucleic acid DNA

If friend look closely, you deserve to see that the two sides of the nucleic mountain strand shown over are different, bring about polarity. In ~ one end of the large molecule, the carbon team is unbound and also at the various other end, the -OH is unbound. These different ends are referred to as the 5"- and also 3"-ends, respectively.

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The Helical framework of DNA

mirrors a solitary strand of DNA. However, as proclaimed earlier, DNA exists together a double-helix, meaning two strands of DNA bind together.

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Figure %: Double-helical DNAAs checked out above, one strand is oriented in the 5" come 3" direction while the complementary strand operation in the 3" come 5" direction. Due to the fact that the 2 strands space oppositely oriented, castle are claimed to be anti-parallel to every other. The two strands bond v their nitrogen bases (marked A, C, G, or T for adenine, cytosine, and also guanine). Note that adenine just bonds with thymine, and also cytosine only bonds with guanine. The nitrogen bases are hosted together through hydrogen bonds: adenine and thymine type two hydrogen bonds; cytosine and guanine kind three hydrogen bonds.

An crucial thing come remember about the framework of the DNA helix is that as a an outcome of anti-parallel pairing, the nitrogen basic groups face the within of the helix when the sugar and phosphate groups face outward. The sugar and phosphate groups in the helix therefore make up the phosphate backbone that DNA. The backbone is very negatively charged together a an outcome of the phosphate groups.