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Capítulo 8

Transcripción: De ADN a ARN

¿Qué es la expresión génica?
¿Qué es la expresión génica?
Overview Gene expression is the process in which DNA directs the synthesis of functional products, that is, proteins. Cells can regulate gene ...
Estructura del ARN
Estructura del ARN
Overview The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...
Estabilidad del ARN
Estabilidad del ARN
Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations ...
ARN polimerasa bacteriana
ARN polimerasa bacteriana
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. ...
Tipos de ARN
Tipos de ARN
Overview Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs ...
Transcripción
Transcripción
Overview Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene ...
Factores de transcripción
Factores de transcripción
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of ...
ARN polimerasas eucariotas
ARN polimerasas eucariotas
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional ...
Proteínas accesorias de la ARN polimerasa II
Proteínas accesorias de la ARN polimerasa II
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, ...
Factores de elongación de la transcripción
Factores de elongación de la transcripción
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not ...
Procesamiento de pre-ARNm
Procesamiento de pre-ARNm
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or ...
Empalme de ARN
Empalme de ARN
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called ...
La estructura de la cromatina regula el procesamiento de pre-ARNm
La estructura de la cromatina regula el procesamiento de pre-ARNm
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into ...
Exportación nuclear de ARNm
Exportación nuclear de ARNm
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several ...
Síntesis de ARN ribosómico
Síntesis de ARN ribosómico
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal ...
Síntesis de ARN de transferencia
Síntesis de ARN de transferencia
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the ...
El Nucléolo
El Nucléolo
The nucleolus is the most prominent substructure of the nucleus. When it was first discovered, it was considered to be an isolated organelle that forms ...
Estructuras subnucleares adicionales
Estructuras subnucleares adicionales
The eukaryotic nucleus is a double membrane-bound organelle that contains nearly all of the cell’s genetic material in the form of chromosomes. It ...
Empalme alternativo de ARN
Empalme alternativo de ARN
Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive ...
Transcripción bacteriana
Transcripción bacteriana
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, ...
Inicio de la transcripción
Inicio de la transcripción
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the ...
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