Choose the best answer.
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1 | |
Gene regulation in eukaryotes may be influenced by: |
| | A) | Environmental conditions. |
| | B) | Developmental stage. |
| | C) | Tissue or cell type. |
| | D) | All of these. |
| | E) | None of these. |
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2 | |
A transcription factor is a protein that affects the ability of RNA polymerase to transcribe a gene. |
| | A) | True |
| | B) | False |
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3 | |
DNA sites bound by regulatory transcription factors: |
| | A) | Are trans acting factors. |
| | B) | Are cis acting factors. |
| | C) | Are promoters. |
| | D) | Have similar sequences in all cells. |
| | E) | None of the above. |
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4 | |
A homodimer: |
| | A) | is a protein with a helix-loop-helix DNA binding motif. |
| | B) | is a protein made of two unique subunits. |
| | C) | is a pair of identical proteins. |
| | D) | typically prevents DNA binding. |
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5 | |
Response elements may be located within the gene itself. |
| | A) | True |
| | B) | False |
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6 | |
In comparing effects of regulatory transcription factors that affect TFIID and those that affect mediator: |
| | A) | TFIID binding prevents transcription while mediator binding allows transcription. |
| | B) | Mediator allows binding of RNA polymerase but transcription can be prevented by transcription factors binding to silencers. |
| | C) | Transcription factors which bind to enhancers stimulate binding of both proteins. |
| | D) | Transcription factors which bind to silencers prevent binding of both proteins. |
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7 | |
Transcription factors, if present, will always bind their appropriate response elements. |
| | A) | True |
| | B) | False |
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8 | |
In the absence of glucocorticoid: |
| | A) | No glucocorticoid receptor is present. |
| | B) | Glucocorticoid receptor is present in an active form. |
| | C) | Glucocorticoid receptor dimerizes to prevent glucocorticoid binding. |
| | D) | All of these. |
| | E) | None of these. |
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9 | |
GREs: |
| | A) | Are located near promoters of many different genes. |
| | B) | Are activated in response to increased glucocorticoid levels. |
| | C) | Are bound by a dimerized regulatory transcription factor. |
| | D) | All of these. |
| | E) | None of these. |
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10 | |
Extracellular signaling molecules: |
| | A) | Are usually able to directly affect transcription. |
| | B) | Are required to enter the cytoplasm and bind a receptor molecule. |
| | C) | Usually bind plasma membrane receptors which then pass along the signal. |
| | D) | Are unable to affect transcription. |
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11 | |
In order for CREB to activate transcription: |
| | A) | It must act as a heterodimer. |
| | B) | It must be phosphorylated. |
| | C) | It must bind to cAMP. |
| | D) | It must bind to RNA polymerase. |
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12 | |
Gene amplification is different from other alterations in DNA structure because: |
| | A) | It is the only alteration that involves loss of DNA. |
| | B) | It is the only alteration that involves addition of DNA. |
| | C) | It is the only alteration that involves changes to the chemical structure of the DNA. |
| | D) | It is the only alteration that involves changes in chromatin structure. |
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13 | |
DNA in an open configuration is more likely to be transcribed than DNA in a closed configuration. |
| | A) | True |
| | B) | False |
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14 | |
Which of the following pieces of DNA would you expect to be most susceptible to DNase-I digestion? |
| | A) | A 30nm fiber. |
| | B) | An 11nm fiber. |
| | C) | An actively transcribed gene. |
| | D) | "Naked" DNA, which is not bound to histones. |
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15 | |
You want to perform a DNase-I protection experiment to see where binding sites for regulatory transcription factors for the mouse calmodulin gene are locateD. What would you use for a probe? |
| | A) | The calmodulin gene coding sequence. |
| | B) | A DNA fragment including about 100bp on either side of the promoter. |
| | C) | A DNA fragment containing several thousand bp upstream of the promoter, one small piece at a time. |
| | D) | Any of these would be useful probes. |
| | E) | None of these would be useful probes. |
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16 | |
A CpG island consists of about 2000 copies of the CG dinucleotide. |
| | A) | True |
| | B) | False |
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17 | |
Housekeeping genes: |
| | A) | Are constitutively expressed. |
| | B) | Have highly methylated CpG islands. |
| | C) | Encode proteins required only in specific tissues. |
| | D) | All of these. |
| | E) | None of these. |
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18 | |
Methylation of CpG islands: |
| | A) | Enhances binding of regulatory transcription factors. |
| | B) | Prevents activation of enhancers. |
| | C) | Prevents binding of chromatin remodeling proteins. |
| | D) | Interferes directly with RNA polymerase binding. |
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19 | |
Methylation of DNA is a heritable trait. |
| | A) | True |
| | B) | False |
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20 | |
The best explanation for interference of DNA methylation with transcription factor binding is: |
| | A) | Methyl-CpG binding protein competes with the transcription factor for binding to methylated DNA. |
| | B) | Methylation of the CpG island modifies the shape of the transcription factor. |
| | C) | Methylation of the CpG island modifies the shape of the response element to which the transcription factor normally binds. |
| | D) | Methylation prevents dimerization of DNA binding proteins. |
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21 | |
A single RNA molecule can encode several different proteins. |
| | A) | True |
| | B) | False |
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22 | |
Two different proteins produced by alternative splicing are most likely to: |
| | A) | Have completely different functions. |
| | B) | Have identical functions. |
| | C) | Have similar functions under different forms of regulation. |
| | D) | Have different functions under similar forms of regulation. |
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23 | |
Control of alternative splicing involves: |
| | A) | Repressors, which cause exon skipping. |
| | B) | Enhancers, which increase recognition of weak splice sites. |
| | C) | Splicing factors, which modulate spliceosome function. |
| | D) | All of these. |
| | E) | None of these. |
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24 | |
In RNA editing, the guide RNA: |
| | A) | Must have the same sequence as the end result of the edited RNA. |
| | B) | Can control the insertion or deletion of uracils. |
| | C) | Can change a uracil to another base. |
| | D) | Can interact with many different RNAs. |
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25 | |
RNA editing: |
| | A) | Is certainly a very rare event. |
| | B) | Occurs in widely varied species. |
| | C) | Probably has only minor effects on RNA function. |
| | D) | All of these. |
| | E) | None of these. |
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26 | |
The length of the poly-A tail has a dramatic effect on RNA stability. |
| | A) | True |
| | B) | False |
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27 | |
The stability of a particular mRNA can be enhanced by: |
| | A) | Presence of destabilizing elements. |
| | B) | A short poly-A tail. |
| | C) | Presence of short bits of antisense RNa. |
| | D) | All of the above. |
| | E) | None of the above. |
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28 | |
Which of these would be the best evidence for a functional role of RNA interference in resistance to viral infection? |
| | A) | Cells resistant to double stranded RNA viruses are also likely to be resistant to single stranded RNA viruses. |
| | B) | Cells resistant to DNA viruses tend not to also be resistant to RNA viruses. |
| | C) | Cells resistant to a single stranded RNA virus tend to be resistant to DNA viruses. |
| | D) | Cells resistant to one double stranded RNA virus tend to be resistant to all double stranded RNA viruses. |
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29 | |
Receptor tyrosine kinases are transmembrane proteins that are activated by binding of an extracellular signal and subsequent phosphorylation of the receptor. Control of the function of receptor tyrosine kinases primarily occurs at what level? |
| | A) | Transcription. |
| | B) | RNA processing. |
| | C) | Translation. |
| | D) | Posttranslational modification. |
| | E) | None of these. |
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30 | |
Changes in function of which of the following proteins by posttranslational modification (such as phosphorylation or acetylation) would be likely to, in turn, affect the expression of specific genes? |
| | A) | TFIID |
| | B) | eIF4F |
| | C) | Histones |
| | D) | IRP |
| | E) | None of these. |
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