Term
| Transcriptional repression is common in ___ and ___ to.... |
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Definition
Bacteria and Archaea
control biosynthesis of molecules (anabolic pathways) |
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Term
| In transcriptional repression, the final product in the biosynthetic pathway often acts as a... |
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Definition
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Term
| What does a co-repressor molecule do? |
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Definition
-Combines with repressor protein to activate it
-Activated repressor blocks transcription
-Leads to stopping production of enzymes to construct a molecule that the cell needs |
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Term
| Which operon is an example of transcriptional repression? |
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Definition
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Term
| Transcriptional induction is common in ___ and ___ to... |
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Definition
Bacteria and Archaea
control degradative (catabolic) pathways |
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Term
| In transcriptional induction, presence of a useful molecule to the cell acts as... |
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Definition
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Term
| What does an inducer molecule do? |
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Definition
Combines with repressor protein to inactivate it
Inactivated repressor allows transcription
Leads to production of enzymes that degrade the useful molecule available to the cell |
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Term
| Which operon is an example of transcriptional induction? |
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Definition
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Term
| In positive control of transcription (like in the mal operon), what must bind to DNA for transcription to proceed? |
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Definition
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Term
| Describe the activator protein in positive transcriptional control. |
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Definition
Activator protein activated by an inducer molecule
Inducer molecule often a compound that is present and useful to the cell
Activator protein binds to DNA allowing RNA polymerase to bind to the promoter site and then transcribe genes
Enzymes necessary for catabolism pathway are synthesized |
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Term
| Positive control of transcription is common in ___ for ... |
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Definition
bacteria
control of catabolism |
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Term
| Synthesis of ___ enzymes that break down ___ are repressed when glucose is present |
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Definition
catabolite
an unrelated compound |
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Term
| Describe the process of catabolite repression. |
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Definition
-Presence of cAMP forms an activated complex with a catabolite activator protein (CAP) at the promoter site and enhances the binding of RNA polymerase
-RNA polymerase transcribes genes to break down polysaccharide into glucose
-Now that glucose is present in cell, ATP cannot be transformed to cAMP and transcription stops
-Repressor substrate (glucose) is a better carbon and energy source than the unrelated compound
-Leads to two exponential growth phases |
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Term
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Definition
-Necessary for RNA processing
-40-400 NT
-Often can also control translation |
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Term
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Definition
-One way sRNAs exert regulatory effects
-Bind to other mRNAs
-Double stranded region prevents translation of mRNA
-Unused mRNA degraded |
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Term
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Definition
-mRNA with region that can bind low MW metabolites
-Found only in some bacteria, fungi, and a few plants
-2% of B. subtilis genes controlled by riboswitches
-Thought to be last vestige of a primitive control mechanism (RNA world) |
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Term
| ____ exert control after mRNA is synthesized |
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Definition
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Term
| In riboswitches, the signal metabolite is typically the product of... |
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Definition
| the biosynthetic pathway encoded for on the mRNA |
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Term
| Describe the region of mRNA that can bind low MW metabolites in riboswitches |
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Definition
Folds into 3D structure that can bind signal metabolite
Amino acids, vitamins, purine bases, GlcN-6-P |
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Term
| Activated riboswitch blocks the... preventing... |
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Definition
| Shine-Dalgarno sequence, preventing further ribosome binding and translation |
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Term
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Definition
| Regulation of transcription by translation |
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Term
| In attenuation, control is exerted when? |
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Definition
| After mRNA syntheses begins but before its completion |
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Term
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Definition
| premature termination of transcription (mRNA synthesis) |
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Term
| Describe the "leader sequence" (attenuation) |
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Definition
Found in first part of mRNA
Region rich in compound to be synthesized by encoded enzymes
Causes mRNA to fold in one of two ways |
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Term
| Attenuation is found in... |
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Definition
| bacterial and probably archaeal cells (NOT EUKS!) |
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Term
| Which operon uses attenuation? |
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Definition
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