- 1(current)
Q. No.Which of the following statements is correct about the role of regulatory proteins in transcription in prokaryotes?
| 1. | They only increase the expression |
| 2. | They only decrease the expression |
| 3. | They interact with RNA polymerase but do not affect the expression |
| 4. | They can act both as activators and as repressors |
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
What would be the actual inducer for the lac operon?
| 1. | lactose | 2. | allolactose |
| 3. | ß-galactosidase | 4. | galactose |
Gene regulation governing lactose operon of E. coli that involves the lac I gene products is:
| 1. | positive and inducible because it can be induced by lactose. |
| 2. | negative and inducible because repress or protein prevents transcription. |
| 3. | negative and repressible because repress or protein prevents transcription. |
| 4. | feedback inhibition because excess of β galactosidase can switch off transcription. |
Expression of the lac operon was completely repressed. This will lead to:
| 1. | The low level of lacZ, lacY, and lacA gene expression will continue. |
| 2. | Allolactose would accumulate within the cell and become toxic. |
| 3. | Lactose would not be converted into the inducer and the operon could not be induced. |
| 4. | The cell will not be able to use glucose as well. |
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
The lac I gene in an E. coli bacterium is mutated. What will be the effect on the regulation of lactose metabolism in this cell?
| 1. | Regulation will be normal. |
| 2. | There will be a constitutive expression of the lac Z gene. |
| 3. | Beta-galactosidase and lactose permease will not be produced in the cell. |
| 4. | The lac repressor will be synthesized continuously at a slow rate. |
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
E. coli cells with a mutated z gene of the lac operon cannot grow in a medium containing only lactose as the source of energy because-
| 1. | They cannot synthesize functional beta-galactosidase |
| 2. | They cannot transport lactose from the medium into the cell |
| 3. | The lac operon is constitutively active in these cells |
| 4. | In the presence of glucose, E. coli cells do not utilize lactose |
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
- 1(current)
Q. No.
© 2024 GoodEd Technologies Pvt. Ltd.