Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chapter 15 Questions
Genetics Chp 15 Questions
| Question | Answer |
|---|---|
| which level is the most energy-efficient way to regulate gene expression | transcriptional regulation is the most energy-efficient, because a cell avoids wasting energy making RNA or protein |
| explain how and alpha helix is able to function as a recognition helix in a transcription factor protein | and alpha helix combined into the major groove of DNA and recognize a specific sequence of bases |
| if a repressor prevents TFIID from binding to the TATA box, why does this inhibit transcription | if TFIID cannot bind to the TATA box, RNA polymerase will not be recruited to the core promoter, and therefore transcription will not begin |
| when an activator protein interacts with the mediator, how does this affect the function of RNA polymerase | when an activator interacts with mediator, it causes mediator to phosphorylate CTD, which causes RNA polymerase to proceed to the elongation phase of transcription |
| explain why the glucocorticoid receptor binds to the next core promoter of some genes, but not next to the core promoter of most genes | the glucocorticoid receptor binds only next to genes that have a GRE by their core promoters |
| combinatorial control refers to the phenomenon that | the combination of many factors determines the expression of any given gene |
| a regulatory transcription factor protein typically contains_____ that binds to the_____ of the DNA | and alpha helix, major groove |
| a bidirectional enhancer has the following sequence 5' GTCA3' 3' CAGT5' which of the following sequences would also be a functional enhancer | 5' TGAC 3' 3' ACTG 5' |
| regulatory transcription factors can be modulated by | -the binding of small effector molecules -protein- protein interactions -covalent modifications |
| how might nucleosome eviction affect transcription | nucleosome eviction may allow certain proteins access to binding to particular sites in the DNA |
| describe two different ways that histone modifications may alter chromatin structure | histone modifications may directly affect the interactions between histones and the DNA, or they may affect the binding of other proteins to the chromatin |
| why is an NFR needed at the core promoter for transcription to occur | an NFR is needed at the core promoter so that activators can recognize enhancers and then the pre-initiation complex can form |
| explain why histone eviction is needed for the elongation phase of transcription | histone eviction or displacement is needed for elongation because RNA polymerase cannot transcribes through nucleosome's. It needs to online the DNA for transcription to take place |
| a chromatin remodeling complex may | -change the locations of nucleosome's -evict nucleosome's from DNA -replace standard histones with histone variants |
| according to the histone code hypothesis, the pattern of histone modifications acts like a language that | influences chromatin structure |
| which of the following characteristics is typical of a eukaryotic gene that can be transcribed | the core promoter is found in a nucleosome free region |
| transcriptional activation of eukaryotic genes involves which of the following events | -changes in nucleosome locations -changes in histone composition within nucleosome's -changes in histone modifications |
| explain why the events in transcriptional silencing via methylation inhibits transcription | DNA methylation is preventing an activator protein from binding to the DNA. This prevents transcriptional activation |
| what is the difference between de novo methylation and maintenance methylation | de novo methylation occurs on unmethylated DNA, whereas maintenance methylation occurs on hemi-methylated DNA |
| how can methylation affect transcription | -it may prevent the binding of regulatory transcription factors -it may enhance the binding of regulatory transcription factors -it may attract the binding of the methyl-CpG-binding proteins, which inhibit transcription |
| the process in which completely on methylated DNA becomes methylated is called | de novo methylation |
| why are insulators important for gene regulation in eukaryotes | insulators prevent one gene from regulating a neighbor gene this allows each gene to control its own regulation |
| insulators may exert their effect by | -acting as a barrier to changes in chromatin structure -blocking the effects of neighboring enhancers |
| the overall goal of the ENCODE project is | to identify all the functional elements in the human genome |
| gene regulation | the phenomenon in which the level of gene expression can vary under different conditions |
| transcription factor | a broad category of proteins that influences the ability of RNA polymerase to transcribed DNA and RNA |
| general transcription factors | one of several proteins that are necessary for basal transcription at the core promoter |
| regulatory transcription factor | a protein or protein complex that binds to a regulatory element and influences the rate of transcription via RNA polymerase |
| control elements regulatory elements regulatory sequence | a sequence of DNA or possibly RNA that binds a regulatory protein and thereby influences gene expression.. Bacterial operator sites in eukaryotic enhancers and silencers are examples |
| activator | a transcriptional regulatory protein that increases the rate of transcription |
| enhancer | a DNA sequence of that functions as a regulatory element. The binding of a regulatory transcription factor to the enhancer increases the level of transcription. |
| represser | a regulatory protein that binds to DNA and inhibits transcription |
| silencer | a DNA sequence that functions as a regulatory element. The binding of a regulatory transcription factor to the silencer decreases the level of transcription |
| combinatorial control | the phenomenon common in eukaryotes in which the combination of many factors determines the expression of any given gene |
| domain | a segment of a protein that has a specific function |
| motif | the name given to a domain or amino acid sequence that functions in a similar manner in many different proteins |
| homodimer | when two polypeptides encoded by the same gene bind to each other to form a dimer |
| heterodimer | when two polypeptides encoded by different genes bind to each other to form a dimer |
| up regulation | genetic regulation that leads to an increase in gene expression |
| down regulation | genetic regulation that leads to a decrease in gene regulation |
| orientation independent | refers to certain types of genetic regulatory elements that can function in the forward or reverse direction certain enhancers are orientation independent |
| bidirectional | the phenomenon in which to replication forks move in opposite directions outward from the origin |
| TFIID | a type of general transcription factor in eukaryotes that is needed for RNA polymerase II function. it binds to the TATA box and recruits RNA polymerase II to the core promoter |
| co-activators | proteins that increase the rate of transcription but do not directly bind to DNA itself |
| transactivation domain | a domain in a transcription factor that activates RNA polymerase |
| mediator | a protein complex that interacts with RNA polymerase II and various regulatory transcription factors. depending on its interactions with regulatory transcription factors, mediator may stimulate or inhibit RNA polymerase II. |
| steroid receptor | a category of transcription factors that respond to steroid hormones. An example is the glucocorticoid receptor |
| glucocorticoid receptor | a type of steroid receptor that functions as a regulatory transcription factor |
| cAMP response element | a short DNA sequence found next to certain eukaryotic genes that is recognized by the cAMP response element binding protein (CREB) |
| chromatin remodeling | a change in chromatin structure that alters the degree of compaction and or the spacing and histone composition of nucleosome's |
| closed confirmation | a tightly packed confirmation of chromatin that cannot be transcribed |
| open confirmation | a loosely packed chromatin structure that is capable of transcription |
| DNA translocase | and ATPase that moves along the DNA. It is a component of chromatin remodeling complexes |
| histone variants | histone proteins whose amino acid sequences are slightly different from the standard histones they often play a specialized role in chromatin structure and function |
| histone acetyltransferase | an enzyme that attaches a acetyl groups to the amino-terminal tails of histone proteins |
| histone code hypothesis | the hypothesis that the pattern of histone modification acts much like a language or code in specifying alterations in chromatin structure |
| chromatin immunoprecipitation sequencing | a technique that is used to determine where any genome a particular protein binds to the DNA |
| DNA methylation | the phenomenon in which an enzyme covalently attach is a methyl group to a base in DNA |
| DNA methyltransferase | the enzyme that attaches methyl groups to adenine and cytosine bases |
| CpG islands | a group of CG sequences that may be clustered near a promoter region of a gene. The methylation of the cytosine bases usually inhibits transcription |
| housekeeping genes | the gene that encodes a protein required in most cells of a multicellular organism |
| tissue specific genes | a gene that is highly regulated and is expressed in a particular cell type |
| methyl-CpG-binding proteins | a protein that binds to a CpG island when it is methylated |
| de novo methylation | the methylation of DNA that has not been previously methylated. This is usually a highly regulated the event |
| maintenance methylation | the methylation of hemimethylated DNA following DNA replication |
| insulator | a segment of DNA that insulates a gene from the effects of nearby regulatory elements, such as enhancers |
| promoter bashing | the approach of making deletions in the vicinity of a promoter is a way to identify the core promoter and regulatory elements |
Created by:
banken