A transcription factor G can act as either a repressor or an activator of operon M, depending on its conformational state.
In one conformational state, transcription factor G binds site 1 in the promoter of operon M. When bound to site 1, it is an activator of operon M transcription. Factor G cannot bind to site 1 if ligand X is bound to it.
When factor G binds to ligand X, factor G undergoes a conformational change such that it now binds site 2 in the promoter and represses operon M. Because of the way in which it acts, ligand X would be called a(n) ____.
Imagine that there is a mutation in the gene that encodes transcription factor G such that operon M is always transcribed.
Which of these mutations in the gene that encodes transcription factor G is consistent with that outcome?
More than one answer may be correct.
'The mutation changes transcription factor G such that it ___'
cannot bind site 1
cannot bind site 2
cannot bind to ligand X
cannot dissociate from ligand X once it has bound
Continuing with the system in Questions 4 and 5, imagine that you are now analyzing mutations in the promoter of operon M. If site 1 is mutated such that factor G cannot bind, operon M will never be ____
repressed
activated
If site 2 is mutated such that factor G cannot bind, operon M will never be ____
repressed
activated
Still on system described in Q4,5,6,7. If there is a mutation in the DNA encoding biosynthesis genes such that ligand X cannot be made, operon M will never be ___
repressed
activated
A transcription factor G can act as either a repressor or an activator of operon M, depending on its conformational state.
In one conformational state, transcription factor G binds site 1 in the promoter of operon M. When bound to site 1, it is an activator of operon M transcription. Factor G cannot bind to site 1 if ligand X is bound to it.
When factor G binds to ligand X, factor G undergoes a conformational change such that it now binds site 2 in the promoter and represses operon M. Because of the way in which it acts, ligand X would be called a(n) ____.
Imagine that there is a mutation in the gene that encodes transcription factor G such that operon M is always transcribed.
Which of these mutations in the gene that encodes transcription factor G is consistent with that outcome?
More than one answer may be correct.
'The mutation changes transcription factor G such that it ___'
| cannot bind site 1 |
| cannot bind site 2 |
| cannot bind to ligand X |
| cannot dissociate from ligand X once it has bound Continuing with the system in Questions 4 and 5, imagine that you are now analyzing mutations in the promoter of operon M. If site 1 is mutated such that factor G cannot bind, operon M will never be ____
|
Related textbook solutions
Related questions
1. What is the term when the product of a biochemical pathway inhibits the activity of the first enzyme of a pathway?
| feedback inhibition. | ||
| activator inhibition. | ||
| diffusional regulation. | ||
| enzyme activation. |
2. Through control of gene expression, prokaryotes respond to changing __________ conditions.
| internal | ||
| protein | ||
| environmental | ||
| genetic |
3. A protein that negatively regulates transcription by binding to the operator is known as the
| operon | ||
| repressor | ||
| activator | ||
| inducer |
4. During attenutation, when tryptophan levels are high, the ________ stem-loop forms and transcription ________ the trpL gene.
| 1-2, ends just past | ||
| 3-4, ends just past | ||
| 1-2, continues beyond | ||
| 3-4, continues beyond |
5. The process of turning on the expression of a gene in response to a substance in the environment is called:
| constituation. | ||
| repression. | ||
| induction. | ||
| catabolism. |
6. What is a function of some specific transcription factors?
| to bind to the promoter region of the gene to facilitate the proper alignment of the RNA polymerase | ||
| to bind to the centromere to induce meiosis | ||
| to bind to enhancer regions to help regulate gene transcription | ||
| to bind to the operator to recruit sigma factor |
7. How does exposing an E.coli cell to glucose affect the regulation of the lac operon via CAP?
| cAMP binds to CAP and transcription is increased. | ||
| cAMP binds to CAP and transcription is decreased. | ||
| cAMP does not bind to CAP and transcription is increased. | ||
| cAMP does not bind to CAP and transcription is decreased. |
8. The lac repressor protein works when mutations in the repressor gene and structural genes are:
| in cis or in trans. | ||
| in trans only. | ||
| in cis only. | ||
| in both prokaryotes and eukaryotes. |
