Name: rna types in gene expression
Uploaded: 2025-05-22T09:05:54.000Z
Duration: 1 min 20 s
Channel: JoVE

K12 Standards

Georgia Standards of Excellence

9-12

Biology

SB2.a

Types of RNA

Hay tres tipos de ARN que tienen un papel directo en la síntesis de proteínas: ARN mensajero o ARNm, ARN de transferencia o ARNt y ARN ribosómico o ARNr.
El ARNm se transcribe primero a partir del ADN mediante emparejamiento de bases complementarias. En una molécula de ARNm, los codones, grupos de tres nucleótidos, especifican la secuencia de aminoácidos e indican dónde debe comenzar y detenerse la síntesis de proteínas.
La traducción se produce después de que el ARNm viaja al citoplasma, donde se posiciona en la pequeña subunidad ribosómica con la ayuda de su ARNr.
A continuación, una molécula de ARNt, con una secuencia de anticodón de tres nucleótidos en un extremo y un aminoácido específico en el otro, se une a un codón complementario en el ARNm.
Los ARNt correctos se unen al ARNm secuencialmente, y el ARNr en la subunidad ribosómica grande cataliza la formación de un enlace peptídico entre dos aminoácidos.
El ribosoma viaja por el ARNm creando un polipéptido con una secuencia de aminoácidos especificada por el ARNm.

tipos de arn

Tres tipos principales de ARN participan en la síntesis de proteínas: el ARN mensajero (ARNm), el ARN de transferencia (ARNt) y el ARN ribosómico (ARNr). Estos ARN realizan diversas funciones y pueden clasificarse en términos generales como ARN codificantes o no codificantes de proteínas. Los ARN no codificantes desempeñan funciones importantes en la regulación de la expresión genética en respuesta a cambios ambientales y de desarrollo. Los ARN no codificantes en procariotas se pueden manipular para desarrollar fármacos antibacterianos más eficaces para uso humano o animal.

El ARN realiza funciones diversas pero cooperativas

El dogma central de la biología molecular establece que el ADN contiene la información que codifica las proteínas y el ARN utiliza esta información para dirigir la síntesis de proteínas.

El ARN mensajero (ARNm) es el ARN codificante de proteínas. Consta de codones: secuencias de tres nucleótidos que codifican un aminoácido específico. El ARN de transferencia (ARNt) y el ARN ribosómico (ARNr) son ARN no codificantes. El ARNt actúa como una molécula adaptadora que lee la secuencia del ARNm y coloca los aminoácidos en el orden correcto en la cadena polipeptídica en crecimiento. El ARNr y otras proteínas forman el ribosoma, el asiento de la síntesis de proteínas en la célula. Durante la traducción, los ribosomas se mueven a lo largo de una cadena de ARNm donde estabilizan la unión de moléculas de ARNt y catalizan la formación de enlaces peptídicos entre aminoácidos. Así, diferentes tipos de ARN realizan funciones específicas pero complementarias durante la síntesis de proteínas.

Los ARN no codificantes en eucariotas regulan la expresión genética

Los ARN no codificantes distintos del ARNt y el ARNr se consideraron inicialmente "basura genómica" ya que no codificaban proteínas. Sin embargo, sus funciones en la regulación de la expresión genética se descubrieron en las últimas décadas y se siguen investigando exhaustivamente. Según su longitud, los ARN no codificantes pueden clasificarse como ARN reguladores pequeños (< 100 nucleótidos) o ARN no codificantes largos (> 200 nucleótidos).

Tanto los ARN reguladores pequeños como los ARN largos no codificantes regulan la expresión génica alterando varias etapas de transcripción y traducción. Los ARN no codificantes afectan el empalme del ARNm: eliminación de segmentos no codificantes y unión de las secuencias codificantes de proteínas. De esta manera controlan la formación de diferentes variantes proteicas a partir de un único gen. Los ARN reguladores pequeños, como los microARN (miARN) y los pequeños ARN de interferencia (ARNip), se unen a secuencias complementarias del ARNm e inhiben la síntesis de proteínas, ya sea bloqueando el acceso de la maquinaria de traducción al ARNm o degradando el propio ARNm. Los ARN largos no codificantes interactúan y reclutan enzimas que modifican químicamente el ADN y las histonas (proteínas que ayudan a empaquetar el ADN en el núcleo) para activar o reprimir la transcripción.

Tipos de ARN

En la síntesis de proteínas intervienen tres tipos principales de ARN: ARN mensajero (ARNm), ARN de transferencia (ARNt) y ARN ribosómico (ARNr). Estos ARN realizan diversas ...

Education

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JoVE Core

Anatomy and Physiology

Anatomía y Fisiología

Unit 1

Unidad 1

Essential Cellular Processes

Procesos celulares esenciales

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

rna types in gene expression

RNA types play different roles in gene expression. RNA, or ribonucleic acid, helps carry and use genetic information in cells. The main types discussed here are messenger RNA, ribosomal RNA, and transfer RNA.

Messenger RNA, or mRNA, carries the genetic code from DNA to the ribosome. The ribosome is the site where proteins are made. Ribosomal RNA, or rRNA, is a key part of the ribosome itself. Transfer RNA, or tRNA, brings the correct amino acids to the ribosome during protein building.

These RNA molecules work together during protein synthesis. mRNA provides the message, rRNA helps form the protein-making machinery, and tRNA matches amino acids to the code. Understanding these RNA types helps explain how cells turn genetic instructions into proteins.

RNA Types in Gene Expression

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types of rna

RNA types play different roles in gene expression. RNA, or ribonucleic acid, helps carry and use genetic information in cells. The main types discussed here are messenger RNA, ribosomal RNA, and transfer RNA. Messenger RNA, or mRNA, carries the genetic code from DNA to the ribosome. The ribosome is the site where proteins are made. Ribosomal RNA, or rRNA, is a key part of the ribosome itself. Transfer RNA, or tRNA, brings the correct amino acids to the ribosome during protein building. These...

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key terms and concepts

Explore messenger RNA, ribosomal RNA, and transfer RNA, and see how each RNA type helps carry and use genetic information during protein synthesis.

RNA Types in Gene Expression | JoVE K12

anatomy and physiology

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The Central Dogma

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Transcription

Translation

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

RNA Types in Gene Expression

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