NUCLEIC ACID

HISTORY

Friedrich Miescher (1844-1895) was the one who started the knowledge of chemistry and the cell nucleus. In 1868, Hoppe-Syler laboratory in Tubingen, he chose pus cells are found in the former wound, and then the cells are dissolved in dilute acid and in this way obtain the cell nucleus that is bound to a protein. By adding a protein enzyme breaker he can get just the cell nucleus and the nucleus of the cell extraction to obtain a substance that dissolves in alkali but insoluble in acid. then this substance called "nuclein" now known as the nucleoprotein. Furthermore demonstrated that the nucleic acid is one of the compounds forming cells and normal tissues. Some of the important function of nucleic acids is to store, menstransmisi, and translating genetic information; metabolism between (intermediary metabolism) and energy information reactions; coenzyme energy carrier; coenzyme transfer of acetic acid, sugars, amino compounds and other biomolecules; coenzyme oxidation reduction reactions . Nucleic acids in the cell there are two types of DNA (deoxyribonucleic acid) or deoxyribonucleic acid and RNA (ribonucleic acid) or ribonucleic acid. Both DNA and RNA in the form anions and is generally bound by the protein and alkaline. For example, the DNA in the nucleus of cells bound to the histones. Joint compound between proteins and nucleic acids disebutnucleoprotein. Nucleic acid molecules such as proteins are polymers but leotida adalahnuk constituent units. ATP is one example of a free nucleic acid nucleotide which acts as an energy carrier.

DEFINITION

Nucleic acids (English: nucleic acid) is a macromolecular complex biochemical, high molecular weight, and composed of nucleotide chains that contain genetic information. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are found in all living cells and viruses. Nucleic acids are so named because of the presence generally in the core (nucleus) cells. Nucleic acids are biopolymers, and its constituent monomers are nucleotides.
Each nucleotide consists of three components, namely a heterocyclic nitrogenous base (purine or pyrimidine), a pentose sugar, and a phosphate group. Nucleic acids are distinguished by the type of sugar found in nucleic acid chains (eg, DNA or deoxyribonucleic acid contains 2-deoxyribose). In addition, the nitrogen bases are found in both types of nucleic acids are different: adenine, cytosine, and guanine can be found in RNA and DNA, while thymine is found only in DNA and uracil can be found only in RNA. Understanding of nucleic acid is very useful in understanding the underlying biochemistry, especially in terms of genetics.

Heterocyclic nitrogenous base (purine or pyrimidine)

 

 

Forms of DNA and RNA

Known to form DNA double helix. Consists of two bands that spiral into one.


 

While RNA molecules have different shapes with DNA. RNA has a single ribbon shape and not twisted.

 

 

The main constituent
DNA is the principal constituent of the ribose sugar loss of one atom of oxygen (deoxyribose).




Each ribbon RNA is a polynucleotide composed of many ribonucleotide. Each ribonucleotide is composed of ribose sugar, nitrogenous base and phosphoric acid.

 

 

Group pospart
Each ribbon / chain double helix made ​​of repeating units called nucleotides. A nucleotide consists of three functional groups: one sugar ribose, triphosphate, and a nitrogenous base.

One thing to remember is the position triphosphate and nitrogen bases attached to ribose. Triphosphat Force attached to the C no 5 'of the ribose


Cluster triphosphate is only held by free nucleotides. While the bound nucleotide chains of DNA loses two phosphate groups, so that only one phosphate that remains.

When nucleotides join the DNA, nucleotides are linked by phosphodiester bonds. Covalent bonding that occurs between phosphate groups on one nucleotide, with the OH group on the other nucleotides. DNA chain so that each would have a 'backbone' phosphate-ribose-phosphate-ribose-phosphate. And so on ..

it can be seen that the 'backbone' of DNA will have the 5 'end (with a free phosphate-bound), and the 3' end (with a free OH group). In the figure, each nucleotide is made of different colors to make it more clear.

Nitrogen bases
In the structure of DNA, ribose sugar and phosphate groups attached to the same. The only difference is in the nitrogenous bases. So actually the differences caused by variations in the composition of the nitrogen bases found in DNA chains. There are four kinds of nitrogenous bases. Adenine, cytosine, Guainne, and thymine.

When these nitrogen bases bound nucleotides, the naming-changed. Remember back in the early explanation of nucleotides. Triphosphate nucleotides consisting of a nitrogenous base, and one that is bound to a ribose molecule. Well .. This nitrogen bases attached to ribose formed if the naming-nucleotide changes.
Adenine triphosphate into 2'deoxyadenosine, cytosin be 2'deoxycytidine triphosphate, guainne be 2'deoxyguanosine triphosphate, and thymine into 2'deoxythymidine triphosphate. Abbreviated as A, C, G, and T.
Note that there are two base pairs are similar. A and G both have two carbon-nitrogen rings, called the class of purine. While the C and T has only one carbon-nitrogen ring, fall into the category pyrimidines.

Cause of the shape of DNA
Interaction of hydrogen bonds between each base nitrogen causes the shape of the two DNA strands be such, is called a double helix shape. This specific interaction occurs between the bases A and T, and C with G. So if the double helix imagined it as a spiral staircase, then ties these bases as its rungs. The width of the 'rungs' is same, because the base pairs always consist of one
primidin and one purine.

DNA can be damaged, called mutations. Substances that cause DNA damage called mutagens, which will change the composition and organization of the DNA. Mutagens can be a powerful oxidizing agent, alkylating agents, as well as electromagnetic radiation such as UV rays, and X-ray Type of damage depends on the type of mutagen. Living creatures that can mutate to die and can also survive, commonly known as mutants.

 

 

RNA

RNA is a polymer composed of a number of nucleotides. Each nucleotide has a phosphate group, a pentose group, and a group of nitrogen bases (base N). Polymer composed of alternating bond between the phosphate group of one nucleotide pentose group of another nucleotide.
The form conformational RNA form double stranded as DNA, but it varies according to the type and function. RNA backbone is composed of a row ribose and phosphate. RNA are ribonucleotides nukleoplasma freely in the form nucleoside triphosphate, such as adenosine triphosphate (ATP), guanosine triphosphate (GTP), sistidin triphosphate (CTP), and uridine triphosphate (UTP). RNA synthesized by DNA in the cell nucleus using DNA as a template.

RNA (ribonucleic acid) or ribonucleic acid is a macromolecule that serves as a storage and channeling of genetic information. RNA as a store of genetic information such as the genetic material of the virus, especially the class of retroviruses. RNA as genetic information as the dealer translation process for the synthesis of proteins. RNA can also function as enzymes (ribozymes) which can mengkalis formation of its own RNA or other RNA molecules.


RNA is a single polynucleotide chain. ? - Cluster phosphate? Purine and pyrimidine associated with ribose to form a molecule called nucleoside or ribonukleosida, which is the basis for the synthesis of DNA precursors. Ribonukleosida associated with phosphate groups form a nucleotide or ribonucleotide. RNA transcription is the result of a DNA fragment, that RNA is a polymer which is much shorter than DNA.

nitrogen bases






Nitrogen bases are divided into two types.
1) purine base composed of Adenine (A)
      and guanine (G).
2) pyrimidine base composed of Cytosine
     (S) and Uracil (U).

RNA structure

differences in DNA and RNA