Both DNA and RNA are known as main point acids. They have actually been given this name for the straightforward reason the they are consisted of of structures called nucleotides. Those nucleotides, themselves consisting of a number of components, bond together to type the double-helix very first discovered through the researchers James Watson and also Francis Crick in 1956. This discovery won the two scientists the Nobel Prize. For now, once we comment on nucleic mountain you need to assume we are discussing DNA rather than RNA, unless otherwise specified.

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Nucleotides

A nucleotide consists of three things: A nitrogenous base, which deserve to be either adenine, guanine, cytosine, or thymine (in the instance of RNA, thymine is replaced by uracil).A five-carbon sugar, called deoxyribose because it is lacking an oxygen team on one of its carbons.One or much more phosphate groups. The nitrogen bases room pyrimidine in structure and form a bond in between their 1" nitrogen and the 1" -OH team of the deoxyribose. This type of bond is referred to as a glycosidic bond. The phosphate group develops a bond v the deoxyribose sugar v an ester bond between one the its negatively fee oxygen groups and the 5" -OH the the sugar ().

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Figure %: A Nucleotide

main point Acids

Nucleotides sign up with together through phosphodiester linkages in between the 5" and 3" carbon atoms to form nucleic acids. The 3" -OH that the street group forms a link with among the negatively charged oxygens of the phosphate group attached to the 5" carbon of another sugar. When plenty of of these nucleotide subunits combine, the an outcome is the big single-stranded polynucleotide or nucleic acid, DNA ()

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Figure %: The Nucleic mountain DNA

If you look closely, you can see the the two sides that the nucleic acid strand shown above are different, causing polarity. At one end of the large molecule, the carbon team is unbound and also at the various other end, the -OH is unbound. These various ends are called the 5"- and 3"-ends, respectively.

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The Helical framework of DNA

mirrors a single strand of DNA. However, as proclaimed earlier, DNA exists as a double-helix, definition two strands of DNA tie together.

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Figure %: Double-helical DNAAs watched above, one strand is oriented in the 5" come 3" direction if the complementary strand operation in the 3" come 5" direction. Due to the fact that the two strands space oppositely oriented, castle are said to be anti-parallel to each other. The 2 strands bond with their nitrogen bases (marked A, C, G, or T for adenine, cytosine, and also guanine). Keep in mind that adenine just bonds through thymine, and also cytosine just bonds through guanine. The nitrogen bases are organized together by hydrogen bonds: adenine and also thymine type two hydrogen bonds; cytosine and guanine form three hydrogen bonds.

An important thing to remember around the structure of the DNA helix is that together a result of anti-parallel pairing, the nitrogen base groups challenge the within of the helix if the sugar and phosphate groups challenge outward. The sugar and phosphate groups in the helix as such make up the phosphate backbone that DNA. The backbone is extremely negatively charged as a result of the phosphate groups.