Term
| Most genes encode _____, and most proteins are _____. The expression of such a gene can be regulated by controlling the _____ of the enzyme or controlling the _____ of enzyme produced |
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Definition
proteins
enzymes
activity
amount |
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Term
| Many metabolic reactions can be regulated through what method |
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Definition
| control of the activities of the enzymes that catalyze them. |
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Term
feedback inhibition is where the
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Definition
| final product of a biosynthetic pathway inhibits the first enzyme unique to that pathway. |
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Term
Covalent modification is a
Enzymes regulated in this way can be |
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Definition
regulatory mechanism for changing the activity of an enzyme.
reversibly modified |
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Term
| how can the amount of an enzyme in a cell be controlled |
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Definition
| by decreasing (repression) or increasing (induction) the amount of mRNA that encodes the enzyme. |
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Term
| in reduction negative control of transcription is used, the regulatory molecule is called a _____ and it functions by inhibiting _____ synthesis |
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Definition
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Term
in induction Inducers may bind to
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Definition
| repressors preventing them from binding to DNA thus activating transcription |
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Term
what happens in the case of the Lac
operon, when lactose is present,
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Definition
| some is converted to allolactose which binds to the repressor and activates transcription |
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Term
All three genes involved in the metabolism of lactose are located
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Definition
| adjacent to each other on the bacterial chromosome |
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Term
what are the 3 genes involved in the metabolism of lactose and their control regions referred to |
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Definition
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Term
•The lac operon contains a short segment of DNA called |
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Definition
|
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Term
| Positive control of transcription is implemented by regulators called |
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Definition
|
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Term
| activator proteins bind to activator-binding sites on the _____ and_____ |
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Definition
| DNA and stimulate transcription |
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Term
activator protein activity is modified by
|
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Definition
|
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Term
| how does positive control of enzyme induction work, |
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Definition
| the effector promotes the binding of the activator protein and thus stimulates transcription. |
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Term
what is the function of Global control systems
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Definition
| to regulate the expression of many genes simultaneously |
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Term
Catabolite repression is a ______, and it helps cells make the most efficient use of ______ sources. |
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Definition
global control system
carbon |
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Term
| The lac operon is underwhat type of two controls |
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Definition
| catabolite repression as well as its own specific negative regulatory system |
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Term
Glucose is a better then lactose in what way , because of this what happens
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Definition
provides a better carbon source
cells prefer to grow on glucose if both carbon sources are available |
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Term
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Definition
The lactose repressor is always synthesized = lactose metabolizing genes are normally turned off
•When lactose is present it is converted to allolactose which acts as an inducer for lactose metabolizing enzymes by binding to the repressor = lactose genes are turned on
•When glucose is also present cAMP is low and the CAP (catabolic activator protein) protein cannot bind the promoter = no transcription of lac genes |
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Term
| what is the stringent response and how is it triggered |
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Definition
| is a global control mechanism triggered by amino acid starvation. |
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Term
| The alarmones guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) are produced by _____, a protein that monitors_____ activity. |
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Definition
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Term
•Alarmones inhibit _____ and _____synthesis |
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Definition
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Term
what is the function of the stringent response |
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Definition
| It achieves balance within the cell between protein production and protein requirements. |
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Term
| When more than one operon is under the control of a single regulatory protein, these operons are collectively called |
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Definition
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Term
| what are some other types of global signals |
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Definition
| cold and heat shock proteins that function to help the cell overcome temperature stress. |
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Term
what is the function of Quorum sensing
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Definition
| allows cells to survey their environment for cells of their own kind |
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Term
Gram negative bacteria communicate using _____ (AHL) as ________ |
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Definition
| acyl-homoserine lactone autoinducers |
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Term
| Gram positive bacteria produce small peptides called ______. |
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Definition
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Term
| ________ uses a two-component system consisting of auto inducer 1 (AI-1) and autoinducer 2 (AI-2) |
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Definition
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Term
what pathogenic bacteria use quorum sensing and what does this do for the cell
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Definition
Pseudomonasto
determine when sufficient numbers are present in the population to overcome host defenses and cause disease |
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Term
what do Pseudomonas do to resist antibiotics
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Definition
|
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Term
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Definition
| is a mechanism whereby gene expression (typically at the level of transcription) is controlled after initiation of RNA synthesis. |
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Term
Attenuation mechanisms involve a coupling of transcription and translation and can therefore occur only in _________. |
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Definition
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