MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 13 Mcqs, each offering curated multiple-choice questions to sharpen your Molecular Biology knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The expression of the tryptophan operon is independent of the availability of tryptophan in culture media. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2. |
Which of the following is true about tryptophan operon? |
| A. | Tetramer of identical subunits |
| B. | The RNA product is very stable |
| C. | The Trp repressor binds to the tryptophan |
| D. | The Trp repressor is the product of the Trp operon |
| Answer» D. The Trp repressor is the product of the Trp operon | |
| 3. |
Tryptophan operon in E. coli is a repressible operon. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4. |
The lac operon is regulated by cAMP by ___________ |
| A. | Binding to lac repressor |
| B. | Binding to operator |
| C. | Binding to promoter |
| D. | Binding to catabolite activator protein |
| Answer» E. | |
| 5. |
Glucose, as the carbon source, is the first choice by bacteria even if other sugars are available. The mechanism behind this selectivity is ___________ |
| A. | Operon repression |
| B. | Glucose utilization |
| C. | Enzyme repression |
| D. | Catabolite repression |
| Answer» E. | |
| 6. |
Which of the following is not present in the -galactosidase structural gene and thus is not transcribed by the same promoter? |
| A. | Lac A |
| B. | Lac I |
| C. | Lac Z |
| D. | Lac Y |
| Answer» C. Lac Z | |
| 7. |
Choose the correct pair among the following. |
| A. | The DNA sequence to which stigma factor binds enhancer |
| B. | The DNA sequence to which RNA polymerase binds operator |
| C. | The DNA sequence that codes for a protein structural gene |
| D. | The DNA sequence to which repressors binds promoter |
| Answer» D. The DNA sequence to which repressors binds promoter | |
| 8. |
Operons are ___________ |
| A. | of approximately uniform size |
| B. | found in some eukaryotes |
| C. | not able to bind to proteins |
| D. | smaller in lower eukaryotes and longer in higher eukaryotes |
| Answer» C. not able to bind to proteins | |
| 9. |
Which of the following is not an example of allosteric regulation? |
| A. | Inactivation of nitrogenase by ADP ribosylation |
| B. | Catabolite repression by CAP in E. coli |
| C. | Regulation of phosphofructokinase activity |
| D. | Regulation of lac operon by allolactose |
| Answer» B. Catabolite repression by CAP in E. coli | |
| 10. |
The proteins of which of the following genes are regularly needed for cellular activity? |
| A. | Regular genes |
| B. | Smart genes |
| C. | Structural genes |
| D. | Housekeeping genes |
| Answer» E. | |
| 11. |
Recruitment of RNA polymerase to the promoter is a ___________ |
| A. | Covalent binding |
| B. | Cooperative binding |
| C. | Protein-protein interaction |
| D. | Van der Waals forces |
| Answer» C. Protein-protein interaction | |
| 12. |
The site where repressor binds the DNA is the ______________ |
| A. | Promoter |
| B. | Terminator |
| C. | Operator |
| D. | ORF |
| Answer» D. ORF | |
| 13. |
In case of transcription which is the rate limiting step? |
| A. | Binding of RNA polymerase |
| B. | Unwinding of DNA duplex |
| C. | Promoter escape |
| D. | Formation of the open complex |
| Answer» B. Unwinding of DNA duplex | |