Both DNA and RNA are recognized as nucleic acids. They have been offered this name for the straightforward reason the they are made up of structures dubbed nucleotides. Those nucleotides, themselves consisting of a number 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 discovery won the two scientists the Nobel Prize. Because that now, when we discuss nucleic acids you must assume us are pointing out DNA rather than RNA, unless otherwise specified.

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A nucleotide is composed of three things: A nitrogenous base, which have the right to be either adenine, guanine, cytosine, or thymine (in the situation of RNA, thymine is replaced by uracil).A five-carbon sugar, dubbed deoxyribose because it is lacking an oxygen group on one of its carbons.One or an ext phosphate groups. The nitrogen bases are pyrimidine in framework and form a bond between their 1" nitrogen and also the 1" -OH team of the deoxyribose. This type of bond is called a glycosidic bond. The phosphate group develops a bond through the deoxyribose sugar v an ester bond in between one that its negatively fee oxygen groups and also the 5" -OH that the sugar ().

Figure %: A Nucleotide

main point Acids

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

Figure %: The Nucleic mountain DNA

If friend look closely, you can see that the 2 sides the the nucleic acid strand shown above are different, bring about polarity. At one finish of the large molecule, the carbon group is unbound and also at the other end, the -OH is unbound. These different ends are dubbed the 5"- and 3"-ends, respectively.

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The Helical structure of DNA

shows a single strand the DNA. However, as stated earlier, DNA exists as a double-helix, definition two strands of DNA bind together.

Figure %: Double-helical DNAAs checked out above, one strand is oriented in the 5" come 3" direction if the security strand operation in the 3" to 5" direction. Due to the fact that the two strands room oppositely oriented, lock are said to it is in anti-parallel to each other. The two strands bond through their nitrogen bases (marked A, C, G, or T because that adenine, cytosine, and also guanine). Keep in mind that adenine only bonds with thymine, and also cytosine only bonds with guanine. The nitrogen bases are hosted together through hydrogen bonds: adenine and thymine kind two hydrogen bonds; cytosine and also guanine form three hydrogen bonds.

An necessary thing come remember around the structure of the DNA helix is that together a result of anti-parallel pairing, the nitrogen base groups confront the within of the helix when the sugar and also phosphate groups confront outward. The sugar and phosphate groups in the helix as such make increase the phosphate backbone the DNA. The backbone is very negatively charged as a result of the phosphate groups.