Central Dogma of Molecular by Enzyme

Central Dogma is all the information contained in DNA, and then will be used to produce RNA molecules through transcription, and partial information in RNA will be used to produce the protein through a process called translation.

Here is the mechanism of the process:

Transcription

This is the initial step in the process of protein synthesis which will process will be continued to the expression of genetic traits that emerged as the phenotype. And to study the molecular biology of basic steps that we have to know is how the mechanism of protein synthesis can be expressed as a phenotype sehingge.

Transcription is the synthesis of RNA molecules in the DNA template. This process occurs in the nucleus of the cell (nucleus) precisely on the chromosomes.

Components involved in the transcription process are: the DNA template comprising the nucleotide bases adenine (A), guanine (G), Thymine (T), Cytosine (S); enzyme RNA polymerase, transcription factors, precursors (ingredients were added as penginduksi).

Results from the synthesis process are the three kinds of RNA, ie mRNA messeger RNA), tRNA (transfer RNA), rRNA (ribosomal RNA).

Before that I will present the first main part of a gene. Gene consisting of: promoter, the structural part (consisting of the genes that encode a trait that will be expressed), and terminator.

While the structure of RNA polymerase: the beta, the beta-prime, alpha, sigma. In the structure of the beta and beta-prime acts as a catalyst in the transcription. Sigma structures to direct the RNA polymerase holoenzim just stick to the promoter. Section called core enzyme consisting of alpha, beta, and beta-prime.

Stages in the transcription process basically consists of three stages, namely:

1. Initiation (escort)

Transcription does not start in any place in the DNA, but in the upstream (upstream) of the promoter gene. One of the most important part of the promoter is a Pribnow box (TATA box). Initiation begins when RNA polymerase holoenzim attached to the promoter. Stages starting from the closed promoter complex formation, the formation of open promoter complex, combining several initial nucleotides, and changes in RNA polymerase conformation because the structure is released from the complex sigma holoenzim.

2. Elongation (elongation)

The next process is the elongation. Here is the elongation elongation nucleotides. After RNA polymerase promoter attached to the enzyme will continue to move along the DNA molecule, unravel and straighten helix. In elongation, the nucleotide added covalently to the 3 'end of newly formed RNA molecule. For example the template DNA nucleotides A, the RNA nucleotides are added is U, and so on. The maximum elongation rate of RNA transcript molecular berrkisar between 30-60 nucleotides per second. Elongation velocity is not constant.

3. Termination (termination)

Termination did not occur in any place. Transcription ends when a specific nucleotide see a STOP codon. Furthermore, irrespective of DNA template RNA to ribosomes.

TRANSLATION

The next stage after transcription is translational. Translation is a translation process that existed at the nucleotide sequence of the mRNA molecule into a series of amino acids that make up a polypeptide or protein.

Required in the translation process are: mRNA, ribosomes, tRNAs, and amino acids.

Before that, I will first explain about the structure of the ribosome. Ribosomes consist of large and small subunits. If both subunits combined to form a monosom. Small subunit contains the peptidyl (P) and aminoacyl (A). While the large subunit contains the Exit (E), P, and A. Both subunits contain one or more rRNA molecules. rRNA is very important to identify bacteria at the level of molecular biology, in prokaryotic and eukaryotic 16 S 18 S.

As with transcription, the translation is also divided into three stages:

1. Initiation

First tRNA binding amino acids, and this led to an activated tRNA or event is called the amino-acylation. Amino-acylation process is catalyzed by the enzyme tRNA synthetase. Then ribosomes experiencing separation into large and small subunits. Selajutnya small subunit attached to the initial codons of mRNA molecules with the attached: 5 '- AGGAGG - 3'. The sequence where the attachment of the small subunit is called Shine-Dalgarno sequence. Small subunit can be attached to the mRNA when IF-3. Complex formation, and IF-3/mRNA-fMet IF-2/tRNA-fMet amino acid called N-formylmethionine, and require a lot of GTP as an energy source. tRNA-fMet and then stick to the small subunit of the P codon opener. Furthermore, large subunit attached to the small subunit. In this process of IF-1 and IF-2 was released and GTP is hydrolysed to GDP, and ready for elongation.

2. Elongation

Differences in the process of transcription, the translation of amino acids lengthen. The step in the process of elongation, the first is the binding of tRNA at the A side in the ribosome. Pemidahan will form a peptide bond.

3. Termination

Translation will be terminated at that time one of the three termination codons (UAA, UGA, UAG) that existed at the mRNA reaches the position A on the ribosome. In E. third coli translational process termination signal is recognized by a protein called a release factor (RF). Posting of RF in termination codons are activated peptidyl transferase enzyme which hydrolyzes the polypeptide DNG tRNA on the P side and causing the empty tRNA had translocated to the E (exit),.

That was the process of transcription and translation mechanisms. The next process is the protein will be expressed by our bodies in shape phenotype.

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