Term
| what is the preferred carbon source for e.coli |
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Definition
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Term
| e.coli can use other sugars but... |
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Definition
| it requires more enzymes meaning more energy to make enzymes so it only uses other sugars if it has to (ie: glucose completely absent) |
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Term
| what is the lac operon involved in |
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Definition
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Term
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Definition
| a gene that is always expressed, a regulatory repressor gene |
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Term
| what regulatory genes are on the DNA encoding for lactose metabolism |
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Definition
| CAP binding site, core promoter, operator |
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Term
| for transcription to occur in favor of lactose metabolism you need |
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Definition
| cAMP/CAP complex bound to CAP binding site, repressor removed from the operator |
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Term
| what happens in the lac opern if glucose is present |
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Definition
| the cAMP/CAP complex is not made because adenyl cyclase is inhibited. the repressor is never removed, RNA polymerase does not transcribe |
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Term
| what happens when glucose isnt present in a lac operon |
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Definition
| adenyl cyclase makes cAMP, cAMP + CAP make the cAMP/CAP complex, complex removes repressor by binding to the CAP binding site, RNA polymerase transcribes |
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Term
| what is the repressor in a lac operon encoded by |
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Definition
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Term
| what initiates the presence of alloacotose |
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Definition
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Term
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Definition
| binds to repressor, prevents binding of repressor to operator, allows RNA polymerase to transcribe |
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Term
| control of gene expression: chromatin modifying activities |
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Definition
| DNA methylation (silences gene regions), Histone acetylation/deacetylation (acetylation neutralizes positive charges on histones, making histone binding weaker) |
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Term
| control of gene expression: specific transctiption factors |
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Definition
| Steriod hormone receptors (example GRE), CREB |
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Term
| control of gene expression: mRNA processing |
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Definition
| Alternative splicing, poly-A tail length |
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Term
| control of gene expression: Rate of Translation |
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Definition
| Regulatory regions on the 5' and 3' UTRs of mRNAs (specific), Activation/inactivation of translation factors (general) |
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Term
| control of gene expression: protein modification |
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Definition
| Inactive precursors (zymogens) for digestive enzymes |
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Term
| control of gene expression: protein degration rate |
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Definition
| PEST sequences in proteins targets them for degradation, so shortens protein half-life |
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Term
| control of gene expression: mRNA Stability |
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Definition
| Half-life of RNA can be modified, ie, poly-A tail length, interaction of 5' and 3' UTR regulatory regions with accessory factors, miRNA targetted degradation of mRNA |
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Term
| eukaryotic genes are by default |
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Definition
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Term
| why are eukaryotic genes usually off |
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Definition
| they are more difficult to transceibe and have a higher chromosome structure and proteins |
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Term
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Definition
| region of DNA that ineracts with a specific transcription factor |
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Term
| where is the enhancer located |
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Definition
| could be close or far from the promoter even on a different strand, can be upsteam or downstream from the promoter |
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Term
| how does the enhancer interact with the promoter if it is far away |
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Definition
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Term
| parts of a transcription factor |
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Definition
| DNA binding domain, activation domain |
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Term
| what does a DNA binding domain do |
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Definition
| recognizes enhancer sequences |
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Term
| what does the activation domain do |
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Definition
| binds to other transcription factors, interacts with RNA polymerase II, stabilizes initiation complex, recruit chromatin modifing proteins (like in histones) |
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Term
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Definition
| insulin dominant, eaten a meal recently, |
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Term
| what does the liver do in the well fed state |
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Definition
| liver removes excess glucose from the blood |
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Term
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Definition
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Term
| what does the liver do in the fasting state |
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Definition
| because glucose drops, the liver releases glucose using glyconeogenesis to make it |
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Term
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Definition
| rate limiting step in gluconeogenesis, unique to gluconeogenesis, |
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Term
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Definition
| under control of glucagon (hypoglycemia) and cortisol (stress, starvation) |
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Term
| what does high glucagon indicate |
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Definition
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Term
| what does the liver release when there is high glucagon |
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Definition
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Term
| how does glucagon induce PEPCK gene expression |
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Definition
| glucagon binds receptor activating edenyl kinase which makes cAMP, cAMP binds protein kinase A, that complex phosphorlyates CREB, p-CREB binds CRE, that complex binds CRE enhancer in the nucleus |
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Term
| what happens when glucagon is present |
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Definition
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Term
| what happens when cortisol is present |
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Definition
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Term
| what happens when cortisol and glucagon are present |
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Definition
| PEPCK is activated even more |
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Term
| how does cortisol induce PEPCK |
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Definition
| cortisol diffuses into hepatocyte. cortisol binds intracellular glucacotricoid receptor, complex enters nucleus, complex binds GRE, PEPCK induced |
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Term
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Definition
| Mechanism of reducing gene expression by either repressing translation or increasing the degradation of specific mRNAs |
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Term
| what role does RNA interference play in cells |
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Definition
| Fundamental role in cell proliferation, differentiation, and apoptosis (so is probably very widely used by cells) |
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Term
| how does RNA interference work |
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Definition
| small miRNA (micro) act as a guide strand to target a mRNA making a double strand region. a protein complex degrades mRNA after noticing a double strand |
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Term
| what protein degrades mRNA with a miRNA on them |
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Definition
| RNA induced silencing complex |
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