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- 1. Multiple Choicewhat is an operon?a part of a ribsomea part of a Rnaa unit made up of linked genes that code for proteins needed to do a specific taskneeded for dna replication
- 2. Multiple ChoiceA protein that binds to the operator and blocks the RNA polymeraseregulatorrepressoractivatorcorepressor
- 3. Multiple ChoiceThe "on/off" switch for an operon is called thepromoterrepressoroperatorgene
- 4. Multiple ChoiceWhat is the name of the stretch of DNA where RNA polymerase binds?operatorpromoterenhancerorigin
- 5. Multiple ChoiceWhat is the role of operons in prokaryote gene expression?It makes the genes prokaryotes be turned onIt accounts for the regulation of gene activity in response to the needs of the cellsTo make DNA for the geneTo make the gene turn of and off
- 6. Multiple ChoiceThe lac operon genes only become expressed if:lactose binds to the repressorglucose binds to the repressorlactose binds to the operatorthe repressor binds to the operator
- 7. Multiple ChoiceIn the lac operon model the genes within the operon will be expressed if:lactose is absent in the cellglucose is present in the celllactose is present in the cell
- 8. Multiple ChoiceInducible negative control is when when the gene is transcribed by the ____ of a specific moleculepresenceabsence
- 9. Multiple ChoiceRepressible negative control is when when the gene is transcribed by the ____ of a specific moleculepresenceabsence
- 10. Multiple Choice
What type of operon is the trp (tryptophan) operon?induciblerepressiblepositive controlpromoible - 11. Multiple ChoiceOperons are found in the cells of which of the following types of organisms?prokaryotes (bacteria)eukaryotes (plant and animals)animals onlyviruses
- 12. Multiple ChoiceHow can a person's muscle cells have the same exact DNA sequences as their nerve cells even though the look and perform completely different?The two different cells become mutatedThe proteins expressed in each cell are differentThey actually have different DNA in the two types of cells.The genome of the different cells changes
- 13. Multiple Choice
lac operon was proposed by
Meselson and Stahl
Jacob and Monod
Hershey and Chase
Watson and Crick
- 14. Multiple Choice
The regulation of an operon by repressor is referred to as
negative regulation
positive regulation
both a and b
neutral regulation
- 15. Multiple Choice
In the lac operon the inducer is
allolactose
glucose
galactose
all of the above
- 16. Multiple ChoiceMost gene regulation happens at which step along the way?translationtranscriptionsignal transductionDNA replication
- 17. Multiple Choice
For a repressible operon to be transcribed, which of the following must be true?
A corepressor must be present.
RNA polymerase and the active repressor must be present.
RNA polymerase must bind to the promoter, and the repressor must be inactive and not blocking the promoter region.
RNA polymerase cannot be present, and the repressor must be inactive.
- 18. Multiple Choice
Which of the following statements regarding the trp operon is true?
The operator region produces the mRNA that codes for the repressor.
The regulatory gene is not transcribed in the presence of the repressor.
Repressor proteins are inactivated by the presence of the repressor. .
The trp operon is always activated unless deactivated by a repressor
- 19. Multiple Choice
Why is the transcription of structural genes of the trp operon turned off in the presence of tryptophan?
Tryptophan is the repressor that binds to the operator, preventing transcription.
The structural genes are used to make tryptophan, which would not be needed if tryptophan is available.
Tryptophan has no effect on the transcription of the structural genes.
Tryptophan RNA polymerase from finding the promoter of the trp operon, preventing structural gene transcription.
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