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 traduzione è il processo di sintesi di una proteina da un modello di RNA messaggero.
Questo processo inizia quando la piccola subunità di un ribosoma, in un complesso con un tRNA metionina e fattori di iniziazione, si lega alle cinque estremità prime di un mRNA. Il complesso scansiona l'mRNA nella direzione da cinque a tre primi fino a quando non incontra un codone AUG che funge da sito di inizio della traduzione.
Successivamente, il tRNA della metionina si accoppia con il codone AUG e recluta la grande subunità del ribosoma. La sintesi della nuova proteina inizia quando un tRNA che trasporta il suo amminoacido si lega al codone successivo dell'mRNA attraverso il suo anticodone.
Questa azione posiziona il nuovo amminoacido vicino all'amminoacido precedentemente incorporato e tra i due amminoacidi si forma un legame peptidico.
La traduzione continua mentre il ribosoma si sposta al codone successivo nella sequenza. Questo movimento in avanti è chiamato traslocazione e continuerà fino a quando il ribosoma non incontra un codone di stop.
I codoni di stop sono unici in quanto non hanno tRNA. Invece, le proteine chiamate fattori di rilascio si legano al codone di stop, inducendo il ribosoma a rilasciare la proteina appena sintetizzata e causando la dissociazione del ribosoma.

traduzione

La traduzione è il processo di sintesi delle proteine dall'informazione genetica trasportata dall'RNA messaggero (mRNA). Dopo la trascrizione, costituisce la fase finale dell'espressione dei geni. Questo processo è effettuato da ribosomi, complessi di proteine e molecole di RNA specializzate. I ribosomi, l'RNA di trasferimento (tRNA) e altre proteine producono una catena di amminoacidi, il polipeptide, come prodotto finale della traduzione.

La traduzione produce gli elementi costitutivi della vita

Le proteine sono chiamate gli elementi costitutivi della vita perché costituiscono la stragrande maggioranza di tutti gli organismi – dalle fibre muscolari ai capelli sulla testa fino ai componenti del sistema immunitario – e il progetto di ciascuna di queste proteine è codificato dai geni presenti nell’organismo. DNA di ogni cellula. Il dogma centrale della biologia impone che l'informazione genetica venga convertita in proteine funzionali mediante processi di trascrizione e traduzione.

La traduzione avviene al di fuori del nucleo

Gli eucarioti hanno un nucleo legato alla membrana dove l'mRNA viene trascritto dal DNA. Dopo la trascrizione, l’mRNA viene espulso dal nucleo per essere tradotto in una catena di amminoacidi – un polipeptide – e infine in una proteina funzionale. Ciò può avvenire nel citoplasma o nel reticolo endoplasmatico rugoso, dove i polipeptidi vengono ulteriormente modificati. Al contrario, i procarioti non hanno un compartimento nucleare, quindi la traduzione nei procarioti avviene nel citoplasma mentre l'mRNA è ancora in fase di trascrizione.

La sequenza dei codoni nell'mRNA determina la sequenza polipeptidica

Ogni codone nell'mRNA corrisponde a uno dei 20 amminoacidi che una cellula mantiene immagazzinata, così come i codoni di stop che non codificano per amminoacidi. Un'altra molecola di RNA, l'RNA di trasferimento (tRNA), è responsabile di fornire l'amminoacido corretto, in base alla sequenza del codone, ai ribosomi durante la traduzione. Ad un'estremità della molecola di tRNA, enzimi chiamati aminoacil-tRNA sintetasi legano covalentemente l'amminoacido specifico al sito di attacco, mentre la sequenza dell'anticodone situata all'altra estremità del tRNA assicura che l'amminoacido corretto venga consegnato al ribosoma. Alcune molecole di tRNA sono in grado di legarsi a più di una sequenza di codoni, consentendo una versatilità di codifica nota come effetto wobble. Ciò è dovuto al fatto che le molecole di tRNA hanno una specificità di legame inferiore al terzo nucleotide nella sequenza del codone dell'mRNA rispetto ai primi due nucleotidi.

Alcune malattie ereditarie derivano da difetti di traduzione

La traduzione è un processo complesso che dipende da una vasta gamma di componenti cellulari. Le mutazioni che influiscono su qualsiasi parte di questo diversificato kit di strumenti possono causare malattie. Ad esempio, l'iperferritinemia della malattia da accumulo di ferro, nota anche come sindrome della cataratta, deriva da mutazioni nella regione 5' non tradotta dell'mRNA, una regione importante per il reclutamento delle proteine di inizio traduzione. Queste mutazioni causano tassi di traduzione anormalmente elevati della proteina ferritina, provocandone l’accumulo nel sangue e nei tessuti dei pazienti affetti. Di conseguenza, le lenti degli occhi diventano opache. Altre malattie sono legate a mutazioni nei geni che codificano i tRNA e le subunità ribosomiali. Ad esempio, la malattia del midollo osseo, l’anemia Diamond-Blackfan, deriva da mutazioni nel gene RPS19, un componente della piccola subunità ribosomiale.

Traduzione

La traduzione è il processo di sintesi delle proteine a partire dall'informazione genetica trasportata dall'RNA messaggero (mRNA). A seguito della trascrizione, costituisce ...

Education

Didattica

JoVE Core

Anatomy and Physiology

Anatomia e Fisiologia

Unit 1

Unità 1

Essential Cellular Processes

Processi cellulari essenziali

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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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types of rna

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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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Meiosis and the Formation of Gametes

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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

Replication in Eukaryotes

Types of RNA

Transcription

Regulation of Expression at Multiple Steps

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Construct an explanation of how the structures of DNA and RNA lead to the expression of information within the cell via the processes of replication, transcription, and translation

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SB2.b

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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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