Transcription in cellular biology is the process of converting DNA into RNA, enabling gene expression. It involves initiation, elongation, and termination phases, with RNA polymerase playing a key role. Eukaryotic cells further modify the RNA transcript through capping, polyadenylation, and splicing to produce mature mRNA. Transcription factors regulate this process, influencing the synthesis of proteins necessary for various cellular functions.
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RNA polymerase binds to the promoter region on DNA, signaling the start of a gene
RNA nucleotides are incorporated into the growing RNA chain
RNA polymerase synthesizes a complementary RNA strand in the 5' to 3' direction
RNA polymerase disengages from DNA upon encountering a specific termination signal, releasing the newly synthesized RNA
In prokaryotes, transcription occurs in the cytoplasm and is carried out by a single RNA polymerase, while in eukaryotes, it takes place in the nucleus and involves multiple RNA polymerases
Capping
The addition of a 5' cap protects mRNA from enzymatic degradation and is essential for efficient translation initiation
Polyadenylation
The addition of a poly(A) tail at the 3' end contributes to mRNA stability and facilitates its export from the nucleus
Splicing
Introns are removed and exons are joined together to produce a mature mRNA that accurately reflects the coding potential of the gene
Transcription factors are proteins that bind to specific DNA sequences and regulate gene expression by acting as activators or repressors
Transcription factors play a crucial role in controlling the synthesis of proteins necessary for various cellular functions, including growth, differentiation, and response to stress
Translation is the process by which the genetic code carried by mRNA is interpreted to synthesize a specific protein
The mRNA produced by transcription serves as the template for protein synthesis during translation
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The process of ______ is crucial for gene expression, involving the conversion of DNA into RNA.
transcription
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Transcription Initiation: Key Components
Assembly of transcription machinery at promoter, DNA unwinding.
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RNA Polymerase Direction During Elongation
Moves 3' to 5' on template strand, synthesizes RNA 5' to 3'.
