Term
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Definition
| multiple genes regulated by the same operator, promoter, and terminator |
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Term
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Definition
| a control switch in the DNA that turns gene expression on or off, usually positioned within the promoter |
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Definition
| an operon whose expression is increased to more than basal levels by an inducer |
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Definition
| molecule that causes increased expression of structural genes in an operon |
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Definition
| an operon whose expression is repressed when a repressor is bound to the operator |
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Definition
| protein that prevents gene expression by binding to DNA sequences or other proteins called silencer sites. they're controlled by hormones or other signals and deac |
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Definition
| protein that binds to repressor proteins and makes them functional |
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Definition
| protein that facilitates gene expression by binding to DNA sequences or other proteins by binding to an enhancer. activators have two regions: one that binds to DNA and one that activates transcription. |
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Term
| positive regulation, give an example |
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Definition
the regulation of gene expression by the binding or an activator protein to DNA
when CAP (an activator) is activated by cAMP, it facilitating the binding of RNA polymerase to the promoter and thereby incraseing the rate of transcritpion, the attachment of CAP to the promoter directly stimulates gene expression |
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Term
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Definition
| the regulation of gene expression by the binding of a repressor protein to DNA |
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Definition
| a gene is always expressed |
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Definition
| enzyme that hydrolyzes lacotse to form glucose and galactose |
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Definition
| membrane protein that facilitates the transport of lactose inside cells |
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Term
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Definition
| enzyme that adds an acetly group to lactose |
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Term
| what controls gene extression in bacteria? |
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Definition
| gene espression in bacteria is controlled by the operon model |
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Term
| how can a cell regulate the production of enzymes? |
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Definition
| a cell can regulate the production of enzymes by feedback inhibition or gene regulation |
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Term
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Definition
| regululation of enzyme activity |
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Term
| regulation of gene expression |
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Definition
| regulation of enzyme production |
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Term
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Definition
| a gene that creates repressors, usually located some distance away from the operon and has its own promoter. regulatory genes are expressed continuously |
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Term
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Definition
| when genes of related function are grouped into one transcription unit that has a single "on-off switch" |
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Term
| where/why do repressible enzymes usually function? |
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Definition
| repressible enzymes generally function in anabolic pathways, which synthasize essential end production from raw materials. by suspending production of an end product when it is already present in sufficent quantity, the call can allocate its organic precursors and energy |
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Term
| where/why do inducible enzymes usually function? |
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Definition
| inducible enzymes usually function in catabolic pathways, which break down a nutrient to simpler molecules. by producing the parroriate enzymes only when the nutrient is available, the cell avoids wasting energy |
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Term
| differential gene expression |
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Definition
| the expression of different genes by cells with the same genome |
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Term
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Definition
| acetyl groups are attached to the lysines in histone tails, deacetlation is the removal of acetly groups. this neutralizes the charges and the histone tails no longe bind to neighboring nucleosomes, giving transcription proteins easier access to genes in an acetylated region |
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Term
| addition of methyl groups to histone tails |
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Definition
| can promote the condensation of the chromatin |
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Term
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Definition
| proposes that the specific combinations of modifications, as well as the order in which they have occurred, help determine the chromatin configuration, which in turn influences transcription |
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Term
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Definition
| enzymes can methylate certain bases in the DNA itself, usually cytosine. long stretches of inactive DNA are usually more methylated than regions of actively transcbried DNA. removal of these extra methyl groups can turn on some of these genes. DNA methylation seems to be essential for long term inactivation of genes |
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Term
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Definition
| inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence |
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Term
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Definition
| segments of noncoding DNA that serve as binding sites for the proteins called transcription factors |
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Term
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Definition
| a distal control element, may be very far upstream or downstream (sometimes even in an intron). however, generally associated with only one gene |
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Term
| where does DNA regulation occur? |
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Definition
| DNA regulation occurs in the chromatin including histone acetylation and DNA demethylation |
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Term
| where does RNA regulation occur? |
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Definition
| RNA regulation occurs in transcription, RNA processing, transport to the cytoplasm, and degradation of mRNA |
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Term
| where does protein regulation occur? |
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Definition
| protein regulation occurs in translation, protein processing such as clevage and chemical modification, degradation of protein, and transport to cellular destination |
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Term
| what happens when methyl is added to a histone tail? |
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Definition
| the chromatin is condensed making transcription more difficult |
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Term
| what is the role of chromatin-modifying enzymes? |
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Definition
| chromatin-modifying enzymes provide initial control of gene expression by making a region of DNA either more or less able to bind the transcription machinery |
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Term
| differences between eukaryotic and prokaryotic gene regulation? |
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Definition
prokaryotes use operons
each co-expressed eukaryotic gene has a promoter and control elements that allow them to be scattered over different chromosomes, but each have the same combination of control elements so that copies of activators can recognize specific control elements and promote simulatneous transcription |
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Term
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Definition
| sites where loos of chromatin extend from individual chromosomal territories into specific sites in the nucleus, some of which are rich in RNA polymerase and other transcription-associated proteins. thought to be areas specialized for a common function |
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Term
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Definition
| an example of regulation at the RNA processing level, occurs when different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns depending on which regulatory protein binds to the regulatory sequences within the primary transcript. alternative RNA splicing can significantly expand the repertoire of a eukaryotic genome |
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Term
| why is the life span of mRNA molecules in the cytoplasm important? |
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Definition
| the life span of mRNA molecules in the cytoplasm is important in determining the pattern of protein synthesis in a cell. |
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Term
| what is the effect of short mRNA life spans? |
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Definition
| short mRNA life spans is one reason bacteria can change their patterns of protein synthesis so quickly in response to environmental changes |
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Term
| what is the effect of long-lived mRNAs? |
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Definition
| long lived mRNAs, such as those in multicellular eukaryotes, are translated repeatedly. |
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Term
| how is a mRNA's life span determined? |
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Definition
| sequences that affect how long an mRNA remains intact are often found in the untranslated region (UTR) at teh 3' end of the molecule |
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Term
| how can gene reguation occur at the initiation of translation? |
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Definition
| regulation at the initiation of translation can occur by blockage by regulatory proteins or the addition of adenine to poly-A tails that lack sufficient length |
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Term
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Definition
| translation of all mRNAs in a cell can be regulated simultaneously, usually by the activation or inactivation of one or more of the protein factors required to initiate translation |
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Term
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Definition
| protein complexes that recognize ubiquitin-tagged proteins and degrade them |
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