Bio: cell and molecular Answer ALL
1 although all of the steps involved in expressing a gene can in principle be regulated, for most genes the initiation of __________ is the most important point of control.
2 the general transcription factors that assemble at a eukaryotic promoter are different, depending on the specific gene being transcribed by polymerase II.
True or False?
3 Which of the following describes the lac operon in E. coli when lactose, but not glucose, is present in the culture medium? A) CAP, but not the lac repressor, is bound to the lac operon's regulatory DNA, and the lac operon is expressed. B) CAP and the lac repressor are both bound to the lac operon's regulatory DNA, and the lac operon is not expressed. C) The lac repressor, but not CAP, is bound to the lac operon's regulatory DNA, and the lac operon is not expressed. D) Neither CAP nor the lac repressor is bound to the lac operon's regulatory DNA, and the lac operon is not expressed.
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Related questions
What role do insulator sequences play in the regulation of eukaryotic transcription?
| A | They block communication between enhancers and nontargeted promoters | |
| B | They block binding of transcription factors to cis-acting promoter elements | |
| C | They block binding of transcription repressors to cis-acting promoter elements | |
| D | They block binding of transcription factors to enhancers | |
| E | They block binding of transcription factors to silencers |
What would be the effect of a mutation in the lacI gene that prevented the repressor from binding to lactose?
| A | The lac Z, Y, and A genes would not be expressed. | |
| B | The lac Z, Y, and A genes would be expressed constitutively | |
| C | The lac Z, Y, and A genes would be repressed by lactose. | |
| D | The lac Z, Y, and A genes would be induced by lactose. | |
| E | The lac Z and Y genes would be repressed but not the lac A gene. |
