Questions? Comments? Please contact Dr. Phillip McClean or Christina Johnson.

OVERVIEW
Flythrough Tour
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MOLECULAR PROCESSES
Transcription
Regulated Transcription
mRNA Processing
mRNA Splicing
Translation
Lac Operon
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CELLULAR PROCESSES
Protein Trafficking
Protein Modification
Protein Recycling
Insulin Signaling
Constitutive Secretion
Regulated Secretion
Mitochondrial Protein Transport
Mitosis
Meiosis
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CELLULAR ENERGY CONVERSION
Atp Synthase (Gradients)
Electron Transport Chain
Photosynthesis (Light Reaction)
Photosystem II
Glycolysis (Overview)
Glycolysis (Reactions)
Citric Acid Cycle (Overview)
Citric Acid Cycle (Reactions)
Energy Consumption
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HOME > TRANSCRIPTION > ADVANCED LOOK > 1.) DNA/TFIID > 2.) Pol II > 3.) ELONGATION
Transcription: Advanced Look --> 3.) Elongation

Elongation is the stage of transcription in which the Pol II complex creates a complementary strand of mRNA. Once the entire transcription unit has been 'copied', the Pol II must release the newly finished strand of mRNA. The general transcription factors involved in the process also release during or at the end of this stage of transcription. Clicking on each of the thumbnail images will bring up a larger, labeled version of the described scene.

To see the Flash movie for the following sequence of images, click here.

Once the ATP have been added, an 'eye' opens in the DNA giving access to the DNA template, and the creation of mRNA can begin.
Once mRNA elongation begins, TFIIE (olive green) and TFIIH (red) are released. Also released at this time are TFIIA and TFIIB (not shown).
TFIIE is shown moving into the distance, and the mRNA strand is elongating rapidly.
Elongation of the mRNA stops when the end of the transcription unit is reached.
As elongation stops, the DNA 'eye' closes.
The Pol II complex is now released from the DNA, along with the phosphates added to it by the ATP.
As the Pol II complex dissociates from the DNA, the mRNA strand is released. At this time, TFIID also unbinds from the DNA, allowing the DNA to return to its normal shape.
Transcription is now complete. An mRNA copy has been produced and is now ready to be moved outside of the nucleus and be used in the translation process.
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