Translation is the ability to translate after encountering the termination code of mRNA

Some. mRNA is translated into proteins.

The initiating aminoyl tr-na of prokaryotic cells is formylmethionyl tRNA (fmet-tRNA

fmet。First, protein initiation factors, GTP, mRNA, ribosomes, etc. were combined into a 70S initiation complex, and after the initiation factors were successively separated from ribosomes, fmet-tRNA

FMET binds to the peptidyl site (p-site) on the 50S subunit of the ribosome and pairs with the start codon AUG on the mRNA, which allows translation to start from the correct start point on the mRNA. The new aminoacyl-tRNA binds to the aminoacyl site (A) of the 50S subunit of the initiation complex in response to the elongation factor and GTP. Catalyzed by enzymes, FMET is detached from tRNA, and its carboxyl group is bonded with the newly entered aminoacyl-tRNA amino group. Then, with the participation of GTP and elongation factors, the tRNA carrying the peptidyl group shifted from A to P, and the ribosome also moved a codon distance along the mRNA from 5 to 3.

At this time, the original unloaded tRNA (tRNA that does not carry amino acids) at the p-position is released. So the next codon enters the A position, waiting for the third aminoacyl-tRNA to enter. These steps are repeated over and over again to allow the peptide bond to grow.

When the stop codon on the mRNA enters the A position, it indicates that the polypeptide chain has been extended to the necessary length. At this time, with the participation of specific protein release factors, the newly synthesized polypeptide chain is hydrolyzed from the tRNA, and the last unloaded tRNA, mRNA and 70S ribosome are released at the same time, which are dissociated into two subunits of 30S and 50S and immediately put into the next cycle to synthesize another new polypeptide chain.

mRNA can form the form of polyribosomes, but not multiple starting points, and if there are multiple starting points, the synthesized protein is not guaranteed to be consistent.

All ribosomes start with the start codon, and after the ribosome in front of it moves a certain distance, the next ribosome reads the start codon (of course, it's actually the hat information first), and so on.

This is difficult to determine, because there are a total of 64 kinds of passwords, three of which are stop codons, and do not determine amino acids, so if there is a password missing from MA, which happens to be the original stop codon, then of course it will not stop in moderation when translating, but it is possible to continue translating until the next stop codon is encountered.

Directed by Zhu Min, Shen Shoulin, Shunji Ohaga, screenwriters Wang Dawei, Zou Jian, Zhang Quan, Wang Peng.

If an mRNA molecule can be used as a template for different peptides, it is possible to stop at a certain site (the junction of two peptides) in the middle of the translation process, and then translate from the next new starting point, so that the individual peptides can be separated without producing a very long peptide chain.

Because the stop signal of gene transcription is not the same as the stop codon of translation, in addition, mRNA will have a poly-A tail at the tail end to increase stability, and these do not contain genetic information. In addition, in some viruses or bacteria, certain RNAs are translated at different locations at the same time, translating different types of proteins.

Not all of them will be translated, there is a non-translation area that will not be translated, and the starting point of translation is AUG.

Take a look at the following paragraph

Untranslated regions (UTR) are non-coding fragments at both ends of messenger RNA (mRNA) molecules. 5'-UTR extends from the methylated guanine nucleotide cap at the origin of the mRNA to the AUG start codon, 3'-UTR extends from the stop codon at the end of the coding region to the end of the poly-A tail.

The termination password does not have an amino Zheng Paic acid corresponding to it, so it is more accurate to say that Bistein! In addition, DNA is divided into coding and non-coding regions! As the name suggests, the shouting of the coding area can be translated.

This situation is impossible, even chromosomal mutations or genetic mutations, etc., can only damage one or a few, and the stop codon on one mRNA is thousands.

Polypeptide chains are made up of amino acids and have no codons on them. Codons are located on messenger RNA (mRNA) strands.

The mRNA of eukaryotes belongs to monocistron mRNA, which has only one start codon and one stop codon on a mRNA strand.

The mRNA of prokaryotes belongs to the polycistronic mRNA, and there are multiple start codons and corresponding stop codons on one mRNA.

The start codon and the stop codon are only found in the DNA and RNA strands. Peptides are simply the aggregation of proteins.

Multiple start codons and multiple stop codons may occur in a DNA strand.

The polypeptide chain is an amino acid residue that has been assembled by ribosomal translation mRNA, and it cannot be said whether there are start codons and stop codons on it. This is an mRNA level.

There may be multiple start codons on a single mRNA, but because of the presence of regulatory elements upstream with conserved sequences, the ribosome can correctly recognize the start position, and translation does not start incorrectly in the middle of the mRNA. There is only one stop codon for a peptide chain translated into an mRNA that ends immediately when encountered.

Some mRNA is translated into a protein The initiating aminoyl tr-na of a prokaryotic cell is formylmethionyl trna (fmet-tnafmet). First, the protein initiation factor, GTP, mRNA, ribosome, etc. are combined into a 70S initiation complex, and after the initiation factor is successively detached from the ribosome, fmet-tRNAfmet binds to the peptidyl position (P position) on the 50S subunit of the ribosome, and pairs with the start codon AUG on the mRNA, which enables the translation to start from the correct start point on the mRNA. The new aminoacyl-tRNA binds to the aminoacyl site (A) of the 50S subunit of the initiation complex in response to the elongation factor and GTP.

Catalyzed by enzymes, FMET is detached from tRNA, and its carboxyl group is bonded with the newly entered aminoacyl-tRNA amino group. Then, with the participation of GTP and elongation factors, the tRNA carrying the peptidyl group shifted from A to P, and the ribosome also moved a codon distance along the mRNA from 5 to 3. At this time, the original unloaded tRNA (tRNA that does not carry amino acids) at the p-position is released. So the next codon enters the A position, waiting for the third aminoacyl-tRNA to enter.

These steps are repeated over and over again to allow the peptide bond to grow. When the stop codon on the mRNA enters the A position, it indicates that the polypeptide chain has been extended to the necessary length. At this time, with the participation of specific protein release factors, the newly synthesized polypeptide chain is hydrolyzed from the tRNA, and the last unloaded tRNA, mRNA and 70S ribosome are released at the same time, which are dissociated into two subunits of 30S and 50S and immediately put into the next cycle to synthesize another new polypeptide chain.