Name: translation: mrna to protein
Uploaded: 2023-06-23T15:38:45.000Z
Duration: 1 min 31 s
Channel: JoVE

K12 Standards

Georgia Standards of Excellence

9-12

Biology

SB2.a

Translation

La traduction est le processus de synthèse d’une protéine à partir d’un modèle d’ARN messager.
Ce processus commence lorsque la petite sous-unité d’un ribosome, dans un complexe avec un ARNt de méthionine et des facteurs d’initiation, se lie à l’extrémité cinq premières d’un ARNm. Le complexe balaie l’ARNm dans la direction cinq premiers à trois premiers jusqu’à ce qu’il rencontre un codon AUG qui sert de site d’initiation de la traduction.
Ensuite, l’ARNt de la méthionine s’apparie au codon AUG et recrute la grande sous-unité du ribosome. La synthèse de la nouvelle protéine commence lorsqu’un ARNt portant son acide aminé se lie au codon suivant de l’ARNm par l’intermédiaire de son anticodon.
Cette action place le nouvel acide aminé à proximité de l’acide aminé précédemment incorporé, et une liaison peptidique se forme entre les deux acides aminés.
La traduction se poursuit lorsque le ribosome se déplace vers le codon suivant de la séquence. Ce mouvement vers l’avant s’appelle la translocation et se poursuivra jusqu’à ce que le ribosome rencontre un codon stop.
Les codons stop sont uniques en ce sens qu’ils n’ont pas d’ARNt. Au lieu de cela, des protéines appelées facteurs de libération se lient au codon stop, incitant le ribosome à libérer la protéine nouvellement synthétisée et provoquant la dissociation du ribosome.

traduction

La traduction est le processus de synthèse de protéines à partir de l'information génétique portée par l'ARN messager (ARNm). Après la transcription, elle constitue l'étape finale de l'expression des gènes. Ce processus est réalisé par des ribosomes, des complexes de protéines et des molécules d'ARN spécialisées. Les ribosomes, l'ARN de transfert (ARNt) et d'autres protéines produisent une chaîne d'acides aminés, le polypeptide, comme produit final de la traduction.

La Traduction Produit les Éléments Constitutifs de la Vie

Les protéines sont appelées les éléments constitutifs de la vie car elles constituent la grande majorité de tous les organismes - des fibres musculaires aux cheveux de votre tête en passant par les composants de votre système immunitaire - et le modèle de chacune de ces protéines est codé par les gènes trouvés dans l' ADN de chaque cellule. Le dogme central de la biologie veut que l’information génétique soit convertie en protéines fonctionnelles par les processus de transcription et de traduction.

La Traduction a Lieu en Dehors du Noyau

Les eucaryotes ont un noyau lié à une membrane où l'ARNm est transcrit à partir de l'ADN. Après la transcription, l’ARNm est expulsé du noyau pour être traduit en une chaîne d’acides aminés - d' un polypeptide - et finalement en une protéine fonctionnelle. Cela peut avoir lieu dans le cytoplasme ou dans le réticulum endoplasmique rugueux, où les polypeptides sont encore modifiés. En revanche, les procaryotes n'ont pas de compartiment nucléaire, donc la traduction chez les procaryotes a lieu dans le cytoplasme pendant que l'ARNm est encore en cours de transcription.

La Séquence de Codons dans l'ARNm Détermine la Séquence Polypeptidique

Chaque codon de l'ARNm correspond à l'un des 20 acides aminés qu'une cellule maintient en stock, ainsi qu'aux codons d'arrêt qui ne codent pas pour les acides aminés. Une autre molécule d'ARN, l'ARN de transfert (ARNt), est chargée de fournir le bon acide aminé, basé sur la séquence de codons, aux ribosomes pendant la traduction. À une extrémité de la molécule d'ARNt, des enzymes appelées aminoacyl-ARNt synthétases attachent de manière covalente l'acide aminé spécifique au site de fixation, tandis que la séquence de l’anticodon située à l'autre extrémité de l'ARNt garantit que l'acide aminé correct est délivré au ribosome. Certaines molécules d'ARNt sont capables de se lier à plus d'une séquence de codons, ce qui permet une polyvalence de codage connue sous le nom d'effet wobble. Cela est dû au fait que les molécules d’ARNt ont une spécificité de liaison plus faible au troisième nucléotide de la séquence de codons de l’ARNm par rapport aux deux premiers nucléotides.

Certaines Maladies Héréditaires Proviennent de Défauts de Traduction

La traduction est un processus complexe qui dépend d’un large éventail de composants cellulaires. Les mutations qui affectent n’importe quelle partie de cette boîte à outils diversifiée peuvent provoquer des maladies. Par exemple, l'hyperferritinémie liée au stockage du fer, également connue sous le nom de syndrome de la cataracte, résulte de mutations dans la région non traduite 5' de l'ARNm, une région importante pour le recrutement des protéines d'initiation de la traduction. Ces mutations entraînent des taux de traduction anormalement élevés de la protéine ferritine, provoquant son accumulation dans le sang et les tissus des patients affectés. En conséquence, les lentilles des yeux deviennent troubles. D’autres maladies sont liées à des mutations dans les gènes codant pour les ARNt et les sous-unités ribosomales. Par exemple, l’anémie Diamond-Blackfan, maladie de la moelle osseuse, résulte de mutations du gène RPS19, un composant de la petite sous-unité ribosomale.

Traduction

La traduction est le processus de synthèse de protéines à partir de l’information génétique portée par l’ARN messager (ARNm). Suite à la transcription, il constitue ...

Education

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JoVE Core

Anatomy and Physiology

Anatomie et physiologie

Unit 1

Unité 1

Essential Cellular Processes

Processus cellulaires essentiels

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

translation: mrna to protein

Translation is the step in gene expression where ribosomes use messenger RNA, or mRNA, to build a protein. The mRNA sequence carries the instructions copied from DNA. During translation, those instructions are read in order so the cell can make a specific chain of amino acids.

This process depends on the ribosome and transfer RNA, or tRNA. The ribosome reads the mRNA, and tRNA brings the matching amino acids. As the chain grows, the amino acids are linked together to form a polypeptide, which is the start of a protein.

Translation is a key part of how cells use genetic information. It connects the message in mRNA to the final protein product. Understanding translation helps explain how genes lead to the molecules that cells need to function.

Translation: mRNA to Protein

the central dogma

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The central dogma explains how genetic information flows in cells from DNA to RNA to protein. It is a core idea in molecular biology and helps show how genes influence cell function. DNA stores the instructions. During transcription, a cell copies a gene into RNA, which is a related nucleic acid. That RNA message can then be used in translation to build a protein. Proteins carry out many jobs in cells and help determine traits. The central dogma links the genetic code in DNA to the molecules...

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translation

Translation is the step in gene expression where ribosomes use messenger RNA, or mRNA, to build a protein. The mRNA sequence carries the instructions copied from DNA. During translation, those instructions are read in order so the cell can make a specific chain of amino acids. This process depends on the ribosome and transfer RNA, or tRNA. The ribosome reads the mRNA, and tRNA brings the matching amino acids. As the chain grows, the amino acids are linked together to form a polypeptide, which...

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regulation-of-expression-at-multiple-steps

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molecular-factors-affecting-cell-division

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key terms and concepts

Learn how translation uses mRNA, ribosomes, and tRNA to build a polypeptide chain from amino acids and turn genetic information into protein.

Translation: mRNA to Protein | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

The Central Dogma

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SB2.c

Obtain, evaluate, and communicate information to analyze how genetic information is expressed in cells

Translation: mRNA to Protein

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