Biology 311C Lecture 35 - November 16, 2011 Biology 311C...

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November 16, 2011 Biology 311C Lecture 35 Final homework will be posted on Monday, November 21 st and will be due Wednesday 30 th by 9 a.m. CLASS IS CANCELLED NEXT WENDESDAY!!! An operon is a sequence of genes controlled by one promoter. In eukaryotic organisms, our DNA is linear and we have multiple chromosomes. Each gene has its own promoter. We have a nucleus and we have RNA processing and transcription factors are needed more. Bacterial cells are singular and we have trillions of cells and specialized tissues. Major control of gene expression is at transcription initiation level. There is a lot of DNA and most of the time, it’s tightly packed. Only when the gene is needed, chromatin is loosed and becomes available. The correct transcription factors and machinery need to be present in the cell. Genes within highly packed heterochromatin are usually not expressed. Histones make up a nucleosome. The histone tails stick out of the nucleosome. Depending on what is attached to the histone tails, you can have chromatin tightly condensed or looser. An acetyl group can be attached to a histone tail by enzymes. If there is an enzyme
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This note was uploaded on 02/21/2012 for the course BIO 311 C taught by Professor Mcclelland during the Fall '09 term at University of Texas at Austin.

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Biology 311C Lecture 35 - November 16, 2011 Biology 311C...

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