ESL505
Presentation 2: Model transcript
DNA Transcription
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Today, I am going to introduce to you the process of DNA transcription in protein synthesis.
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Transcription is the process in which a DNA sequence is copied by an RNA polymerase to produce
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a complementary strand of RNA. In other words, it is the process through which genetic information
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is transferred from DNA to RNA. In the case of a protein-encoding DNA, transcription ultimately
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leads to the production of a functional peptide or protein, a process that happens frequently in all
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cells. The process of transcription can be divided into three stages: initiation, elongation, and
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termination.
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Transcription starts with initiation. Transcription requires only one strand of the DNA double
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helix. This is called the template strand. RNA polymerase, an enzyme, binds to a specific region of
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DNA on the template strand that designates the starting point of transcription. This binding region
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is called the promoter. As the RNA binds to the promoter, the DNA strands begin to unwind.
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The second step of transcription is elongation. The RNA polymerase travels along the
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template strand and unwinds the DNA double helix, adding ribonucleotides continuously. Through
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elongation, a strand of messenger RNA is synthesized whose base sequence is exactly
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complementary to that of the template strand.
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Chain elongation continues until the third and final stage, termination, when the enzyme
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encounters a second signal in the DNA called the terminator. When the RNA polymerase reaches
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the terminator, it stops and releases both the template DNA and the newly made RNA chain.
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During this stage, modifications are made to the newly transcribed RNA so that it can travel to the
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ribosome, where translation from RNA to protein takes place. Finally, the synthesized RNA is used
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to produce a peptide or protein.
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Thank you for listening to me talk about DNA transcription, which includes three stages:
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initiation, elongation and termination. I hope this gives you a brief idea about DNA transcription, a
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small part of the larger process that allows our bodies to produce the proteins we need to live.
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Now, I’d be happy to answer any of your questions.
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Word count: 346