average = 79
Post on 02-Jan-2016
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Exam 1 grade distribution
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0-59 60-64 65-69 70-74 75-79 80-84 85-89 90-94 95-100
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Exam II grade distribution
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0-59 60-64 65-69 70-74 75-79 80-84 85-89 90-94 95-100
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Average = 79
Average = 85
The lac operon promoter
LacZ - BetaGalactosidase - cleaves lactose into usable subunits
LacY - Lactose permease - transports lactose across the cell membrane
LacA - Eliminates toxic molecules that are co-transported
Operator - Binds repressors
CAP site - binds cap proteins (activator)
The cap activator is a helix-turn-helix motif
-Bind DNA as a dimer
-Requires two similar sequences of DNA in reverse order
Regulation in eukaryotes follows the same principles as prokaryotes, but involves more regulatory sequences
- *Can regulate access to DNA via nucleosomes
Transcriptional regulators (tx factors) are modular
- Experimental loss of n-terminal end of activator
- Experimental fusion of n-terminal domian of an activator to c terminal of a repressor
Eukaryotic activators don’t often interact directly with RNA polymerase
Interaction with the mediator complex
Interaction with histones
Example of signal transduction
- Extracellular signaling molecule (ie SHH) initiates a cascade that alters transcription
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