Transcription of DNA to RNA

Transcription of DNA to RNA

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  Wednesday 28, March,2012. Biology: Oscar Gonzalez Team: Rafael Oswaldo Sandoval Rodríguez Serrano Edgar Humberto Tramontini Tapia Mayko Vittorio Williams Reyes Fernando Lamar
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  The Structure ofRNA  What is the function of RNA?  DNA carries the genetic code that produces proteins needed in our body. Among the DNA, there are bases sequences or genes that are a coded description for making a particular protein.  We must know that proteins are not made inside the nucleus of a cell, but rather outside of it, in the cytoplasm, and to accomplish that, we need RNA.
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  The Structure ofRNA  First, RNA copies the information with a slight change (which will be seen later). Then, it proceeds to go outside the nucleus into the cytoplasm and synthesize the information with the ribosomal RNA and the transfer RNA.
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  The Structure ofRNA  How to differentiate RNA from DNA?  The length is a very considerable variable, since DNA is much longer because it contains the information for making every protein we need, while mRNA contains the information to transcribe one protein or polypeptide chain.  Their overall structure is also different, being DNA one a double helix, and mRNA a single stranded one.
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  The Structure ofRNA  The sugar present in the back bone of the chain.  In the RNA back bone, the deoxyribose group found in DNA is replace by a sugar ribose.  A different base.  DNA bases are Adenine, Guanine, Cytosine and Thymine, represented by their first letter, but in RNA, Thymine is replaced by Uracil.
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  The Structure ofRNA
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  DNA Strands
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  Steps of Transcription Pre-Initation:  RNA polymerase and cofactors bind to DNA and unwind it, creating an initiation bubble. This is a space that grants RNA polymerase access to a single strand of the DNA molecule.
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  Steps of Transcription Initiation:  A group of proteins called transcription factors mediate the binding of RNA polymerase and the initiation of transcription.
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  Steps of Transcription Promoter Clearance:  RNA polymerase must clear the promoter once the first bond has been synthesized. Approximately 23 nucleotides must be synthesized before RNA polymerase loses its tendency to slip away and prematurely release the RNA transcript.
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  Steps of Transcription Elongation:  One strand of DNA serves as the template for RNA synthesis, but multiple rounds of transcription may occur so that many copies of a gene may be produced.
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  Steps of Transcription Termination:  Termination results in the release of the newly synthesized mRNA from the elongation complex.
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  References  http://www.chemguide.co.uk/organicprops/aminoaci ds/dna3.html  http://biology.about.com/od/cellularprocesses/ss/Dna -Transcription.htm
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  Questionare  Define transcription: What is the function of RNA?  In the DNA´s structure, thymine is replaced by what base in the RNA´s structure?  The is a very considerable variable, since is much longer because it contains the information for making every protein we need, while mRNA contains the information to transcribe one protein or polypeptide chain. Their overall structure is also different, being DNA one a , and mRNA a single stranded one.
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  Questionare  Define depre-initiation step:  Establish the diference between elongation and termination:  Mention 5 diferences between the DNA´s structure and the RNA´s structure:
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  Excersice  DNA strand: A T T A C G A T C T G C A C A A G A C T T C  Transcription  MRNA strand: __________________________________________   DNA strand: G T A C G A A T T G C C A A T T A C T  Transcription  MRNA strand: __________________________________________   DNA strand: T A C G G A A T C G A T G C G C G C A C T  Transcription  MRNA strand: __________________________________________   DNA strand: T A C C C A T G G G G A A A T A T C  Transcription  MRNA strand: __________________________________________   DNA strand: G C G C T A C A A T T G G A T C G T  Transcription  MRNA strand: __________________________________________