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

A tradução é o processo de sintetizar uma proteína a partir de um molde de RNA mensageiro.
Esse processo começa quando a pequena subunidade de um ribossomo, em um complexo com um tRNA de metionina e fatores de iniciação, se liga às cinco extremidades primas de um mRNA. O complexo varre o mRNA na direção de cinco a três primos até encontrar um códon AUG que serve como local de iniciação da tradução.
Em seguida, o tRNA de metionina emparelha com o códon AUG e recruta a grande subunidade do ribossomo. A síntese da nova proteína começa quando um tRNA carregando seu aminoácido se liga ao próximo códon do mRNA por meio de seu anticódon.
Essa ação coloca o novo aminoácido próximo ao aminoácido previamente incorporado, e uma ligação peptídica se forma entre os dois aminoácidos.
A tradução continua à medida que o ribossomo se move para o próximo códon na sequência. Esse movimento para frente é chamado de translocação e continuará até que o ribossomo encontre um códon de parada.
Os códons de parada são únicos porque não possuem tRNAs. Em vez disso, proteínas chamadas fatores de liberação se ligam ao códon de parada, induzindo o ribossomo a liberar a proteína recém-sintetizada e fazendo com que o ribossomo se dissocie.

tradução

<h4>Tradução</h4>

A tradução é o processo de síntese de proteínas a partir da informação genética transportada pelo RNA mensageiro (mRNA). Ocorrendo após a transcrição, ela constitui a etapa final na expressão dos genes. Este processo é realizado por ribossomos, complexos de proteínas e moléculas especializadas de RNA. Os ribossomos, o RNA de transferência (tRNA) e outras proteínas produzem uma cadeia de aminoácidos – o polipeptídeo – como produto final da tradução.

<h4>A tradução produz os alicerces da vida</h4>

As proteínas são chamadas de blocos de construção da vida porque constituem a grande maioria de todos os organismos - desde fibras musculares até os cabelos da cabeça e componentes do sistema imunológico - e o projeto de cada uma dessas proteínas é codificado pelos genes encontrados no DNA de cada célula. O dogma central da biologia determina que a informação genética seja convertida em proteínas funcionais pelos processos de transcrição e tradução.

<h4>A tradução ocorre fora do núcleo</h4>

Os eucariotos têm um núcleo ligado à membrana onde o mRNA é transcrito do DNA. Após a transcrição, o mRNA é transportado para fora do núcleo para ser traduzido em uma cadeia de aminoácidos – um polipeptídeo – e, eventualmente, em uma proteína funcional. Isto pode ocorrer no citoplasma ou no retículo endoplasmático rugoso, onde os polipeptídeos são posteriormente modificados. Em contraste, os procariontes não possuem um compartimento nuclear, de modo que a tradução nos procariontes ocorre no citoplasma enquanto o mRNA ainda está sendo transcrito.

<h4>A sequência de códons no mRNA determina a sequência polipeptídica</h4>

Cada códon no mRNA corresponde a um dos 20 aminoácidos que uma célula mantém estocado, bem como códons de parada que não codificam aminoácidos. Outra molécula de RNA, o RNA de transferência (tRNA), é responsável por fornecer o aminoácido correto, com base na sequência de códons, aos ribossomos durante a tradução. Em uma extremidade da molécula de tRNA, enzimas chamadas aminoacil-tRNA sintetases ligam covalentemente o aminoácido específico ao local de ligação, enquanto a sequência de anticódon localizada na outra extremidade do tRNA garante que o aminoácido correto seja entregue ao ribossomo. Algumas moléculas de tRNA são capazes de se ligar a mais de uma sequência de códons, permitindo uma versatilidade de codificação conhecida como efeito de oscilação. Isto deve-se ao facto de as moléculas de ARNt terem menor especificidade de ligação ao terceiro nucleótido na sequência de codões de ARNm em comparação com os dois primeiros nucleotídeos.

<h4>Algumas doenças hereditárias resultam de defeitos de tradução</h4>

A tradução é um processo complexo que depende de uma ampla gama de componentes celulares. Mutações que afetam qualquer parte deste conjunto diversificado de ferramentas podem causar doenças. Por exemplo, a hiperferritinemia, doença de armazenamento de ferro, também conhecida como síndrome de catarata, resulta de mutações na região 5' não traduzida do mRNA, uma região que é importante para o recrutamento de proteínas de iniciação da tradução. Essas mutações causam taxas anormalmente altas de tradução da proteína de ferro, a ferritina, fazendo com que ela se acumule no sangue e nos tecidos dos pacientes afetados. Como resultado, as lentes dos olhos ficam turvas. Outras doenças estão ligadas a mutações nos genes que codificam os tRNAs e as subunidades ribossômicas. Por exemplo, a doença da medula óssea, a anemia Diamond-Blackfan, decorre de mutações no gene RPS19, um componente da pequena subunidade ribossômica.

Tradução

A tradução é o processo de síntese de proteínas a partir da informação genética transportada pelo RNA mensageiro (mRNA). Após a transcrição, constitui ...

Education

JoVE Core

Anatomy and Physiology

Anatomia e Fisiologia

Unit 1

Unidade 1

Essential Cellular Processes

Processos Celulares Essenciais

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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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what is meiosis?

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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

O JoVE Core Anatomia e Fisiologia apresenta detalhes anatômicos e fisiológicos do corpo humano em animações  abrangentes, claras e envolventes. Esta coleção de vídeos se concentra nas estruturas, componentes, funções e requisitos do corpo humano. É complementada por vídeos de cientistas em ação que demonstram a aplicação desse conhecimento em instalações médicas e de pesquisa do mundo real.

The Central Dogma

Replication in Eukaryotes

Types of RNA

Transcription

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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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