List+of+Figures+and+Tables+for+Exam+3

List+of+Figures+and+Tables+for+Exam+3 - List of Figures for...

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List of Figures for Exam 3 Genetics 7.4 structure of DNA 7.5 computer model of DNA 7.8d supercoiled chromosomal DNA in a prokaryote 7.9 DNA wound around histone proteins to form a nucleosome in a eukaryote 7.2a prokaryote gene structure - no introns, all coding; transcription – cotranscription occurs where genes in an operon are transcribed together to form a single polycistronic mRNA that will be processed to yield individual mRNAs; transcription and translation occur in the cytoplasm; each mRNA open reading frame is translated to protein. 7.2b eukaryote gene structure – introns intervene exons; transcription – cotranscription does not occur, introns are spliced out and only exons remain in single mRNA; transcription occurs in the nucleus; mRNA is translated into protein in the cytoplasm. 7.30 sigma factor attaches to RNA polymerase II; the sigma factor recognizes the promoter to allow transcription by RNA polymerase II 7.29 prokaryote transcription 7.31 transcription factors help eukaryote RNA polymerase II bind to promoter 7.33 example of an operon – several genes located adjacent to one another under the control of a single promoter 8.11 Enzyme repression – example arginine biosynthesis - enzymes needed to make arginine are made by the cell if arginine is not in the growth medium; upon the addition of arginine to the growth medium, the cell no longer has to make its own arginine so the arginine biosynthesis enzymes are repressed (no longer transcribed). 8.12 Enzyme induction – example lactose catabolism – enzymes needed to break down lactose are repressed until lactose is added to the growth medium; lacZ encodes β- Galactosidase and is the first gene of the lac operon that is transcribed following induction. 8.13 arg operon as an example of enzyme repression as a negative control of transcription: in the absence of arginine in the media/environment, the cell has to make its own, therefore the arginine repressor does not block transcription of arginine biosynthetic genes and there is cotranscription of argC , argB , and argH ; if arginine is present in the media/environment, the cell does not have to make its own, therefore the arg operon is repressed by binding of arginine to the arginine repressor allowing the repressor to bind the arg operator to block transcription. 8.14 lac operon as an example of enzyme induction as a negative control of transcription: in the absence of lactose, the lac operon is repressed and transcription is blocked; in the presence of lactose (the inducer), the lac operon is induced and cotranscription of lacZ , lacY , and lacA occurs so that lactose can be broken down and used as an energy source by the cell. 8.20
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List+of+Figures+and+Tables+for+Exam+3 - List of Figures for...

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