MCQOPTIONS
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MCQOPTIONS
This section includes 39 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
How many types of skin cancers can develop by overexposure to ultraviolet rays? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 2. |
Xeroderma pigmentosum is caused by ______________________ |
| A. | UV radiations |
| B. | X-rays |
| C. | Gamma radiations |
| D. | Beta-rays |
| Answer» B. X-rays | |
| 3. |
The NHEJ pathway is used to rectify __________________ in the DNA. |
| A. | nucleotide substitutions |
| B. | double-strand breaks |
| C. | single-strand breaks |
| D. | mismatched basepairs |
| Answer» C. single-strand breaks | |
| 4. |
Which of the following does not introduce double-strand breaks in the DNA? |
| A. | Gamma rays |
| B. | Cancer drugs |
| C. | Free radicals |
| D. | Inherited mutations |
| Answer» E. | |
| 5. |
A mismatched base pair can cause ________________ in the double helix. |
| A. | change in geometry |
| B. | change in location |
| C. | change in size |
| D. | change in alkalinity |
| Answer» B. change in location | |
| 6. |
Which repair system operates to repair DNA strands that are actively transcribed? |
| A. | Double-strand breakage repair |
| B. | Nucleotide excision repair |
| C. | RNA repair |
| D. | Messenger RNA repair |
| Answer» C. RNA repair | |
| 7. |
Which repair system operates to remove the altered bases generated by reactive chemicals present in the diet? |
| A. | Base excision repair |
| B. | Nucleotide excision repair |
| C. | Mismatch repair |
| D. | Double-stranded breakage repair |
| Answer» B. Nucleotide excision repair | |
| 8. |
How many pathways of nucleotide excision repair exist? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 9. |
Mutations in the DNA may be passed to the next generation. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 10. |
Mark the one, which is CORRECT for SOS repair. |
| A. | RecA protein participates |
| B. | A free radical mechanism is involved |
| C. | The repair enzyme functions only once |
| D. | No bases or nucleotides are removed |
| Answer» B. A free radical mechanism is involved | |
| 11. |
Which of the following is NOT the function of the enzyme systems involved in mismatch repair? |
| A. | Recognize mismatched base pair |
| B. | Gene conversion |
| C. | Determine incorrect base from a mismatch |
| D. | Excise incorrect base and carry out repair system |
| Answer» C. Determine incorrect base from a mismatch | |
| 12. |
The correction of changes in DNA by a set of process known as___________ |
| A. | Replication |
| B. | DNA repair |
| C. | Translation |
| D. | Transcription |
| Answer» C. Translation | |
| 13. |
The enzyme photolyase is used in what method of repair? |
| A. | Base excision |
| B. | Photo reactivation |
| C. | Nucleotide excision |
| D. | None of the mentioned |
| Answer» C. Nucleotide excision | |
| 14. |
Recombinational repair is often due to ____________ |
| A. | Incorporation of many incorrect nucleotides by DNA pol |
| B. | Many cystidine dimer and associated large gaps in a strand |
| C. | Many thymidine dimer formations and associated large gaps in a strand |
| D. | All of the mentioned |
| Answer» D. All of the mentioned | |
| 15. |
The enzyme of E.coli is a nuclease that initiates the repair of double stranded DNA breaks by homologous recombination is? |
| A. | DNA glycosylase |
| B. | DNA ligase |
| C. | DNA polymerase |
| D. | RNA polymerase |
| Answer» B. DNA ligase | |
| 16. |
A point mutation that replaces a purine with another purine, or a pyrimidine with another pyramidine ____________ |
| A. | Nonsense mutation |
| B. | Silent mutation |
| C. | Transition mutation |
| D. | Transversion |
| Answer» D. Transversion | |
| 17. |
An alteration in a nucleotide sequence that changes a triplet coding for an amino acid into a termination codon is ____________ |
| A. | Nonsense mutation |
| B. | Mutagenesis |
| C. | Mutation |
| D. | Mutagen |
| Answer» B. Mutagenesis | |
| 18. |
The DNA polymerase involved in base excision repair is ____________ |
| A. | DNA polymerase α |
| B. | DNA polymerase β |
| C. | DNA polymerase σ |
| D. | DNA polymerase γ |
| Answer» C. DNA polymerase σ | |
| 19. |
What is the function of enzyme involved in base excision repair? |
| A. | Addition of correct base |
| B. | Addition of correct nucleotide |
| C. | Removal of incorrect base |
| D. | Removal of phosphodiester bond |
| Answer» D. Removal of phosphodiester bond | |
| 20. |
If the mutation has a negligible effect on the function of a gene, it is known as a ____________ |
| A. | Silent mutation |
| B. | Frame shift mutation |
| C. | Substitution mutation |
| D. | Insertion mutation |
| Answer» B. Frame shift mutation | |
| 21. |
WHICH_OF_THE_FOLLOWING_IS_NOT_THE_FUNCTION_OF_THE_ENZYME_SYSTEMS_INVOLVED_IN_MISMATCH_REPAIR??$ |
| A. | Recognize mismatched base pair |
| B. | Gene conversion |
| C. | Determine incorrect base from a mismatch |
| D. | Excise incorrect base and carry out repair system |
| Answer» C. Determine incorrect base from a mismatch | |
| 22. |
RECOMBINATIONAL_REPAIR_IS_OFTEN_DUE_TO?$ |
| A. | Incorporation of many incorrect nucleotides by DNA pol |
| B. | Many cystidine dimer and associated large gaps in a strand |
| C. | Many thymidine dimer formation and associated large gaps in a strand |
| D. | All of these |
| Answer» D. All of these | |
| 23. |
Mark_the_one,_which_is_CORRECT_for_SOS_repair.$ |
| A. | RecA protein participates |
| B. | A free radical mechanism is involved |
| C. | The repair enzyme functions only once |
| D. | No bases or nucleotides are removed |
| Answer» B. A free radical mechanism is involved | |
| 24. |
The_enzyme_photolyase_is_used_in_what_method_of_repair |
| A. | Base excision |
| B. | Photo reactivation |
| C. | Nucleotide excision |
| D. | None of these |
| Answer» C. Nucleotide excision | |
| 25. |
Mark the one, which is NOT a subunit of ABC exinuclease? |
| A. | UvrA |
| B. | UvrB |
| C. | UvrC |
| D. | UvrF |
| Answer» E. | |
| 26. |
The enzyme of E.coli is a nuclease that initiates the repair of double stranded DNA breaks by homologous recombinatio? |
| A. | DNA glycosylase |
| B. | DNA ligase |
| C. | DNA polymerase |
| D. | RNA polymerase |
| Answer» B. DNA ligase | |
| 27. |
Which of the following enzyme works in the nucleotide excision repair? |
| A. | DNA photolyase |
| B. | ABC exinuclease |
| C. | DNA glycosylase |
| D. | RecA |
| Answer» C. DNA glycosylase | |
| 28. |
A point mutation that replaces a purine with another purine, or a pyrimidine with another pyramidine |
| A. | Nonsense mutation |
| B. | Silent mutation |
| C. | Transition mutation |
| D. | Transversion |
| Answer» D. Transversion | |
| 29. |
Name the enzyme which initiates base excision repair process? |
| A. | RNA polymerase |
| B. | DNA polymerase |
| C. | DNA photolyase |
| D. | DNA glycosylase |
| Answer» E. | |
| 30. |
An alteration in a nucleotide sequence that changes a triplet coding for an amino acid into a termination codon is |
| A. | Nonsense mutation |
| B. | Mutagenesis |
| C. | Mutation |
| D. | Mutagen |
| Answer» B. Mutagenesis | |
| 31. |
Name the repair system which involves the removal of the damaged segment of DNA? |
| A. | Recombinational repair |
| B. | Direct repair |
| C. | Excision repair |
| D. | Mismatched repair |
| Answer» D. Mismatched repair | |
| 32. |
The DNA polymerase involved in base excision repair is |
| A. | DNA polymerase α |
| B. | DNA polymerase β |
| C. | DNA polymerase σ |
| D. | DNA polymerase γ |
| Answer» C. DNA polymerase ‚âà√¨‚àö√¢ | |
| 33. |
Which of the following enzyme is used in photoreactivation process? |
| A. | DNA ligase |
| B. | DNA photolyase |
| C. | DNA polymerase |
| D. | Primase |
| Answer» C. DNA polymerase | |
| 34. |
The function of enzyme involved in base excision repair is |
| A. | Addition of correct base |
| B. | Addition of correct nucleotide |
| C. | Removal of incorrect base |
| D. | Removal of phosphodiester bond |
| Answer» D. Removal of phosphodiester bond | |
| 35. |
Name the repair system for UV mediated damage of DNA? |
| A. | Exchange of homologous segments |
| B. | DNA glycosylase |
| C. | Nucleotide excision repair |
| D. | Photoreactivation |
| Answer» E. | |
| 36. |
Which of the following has the self-repairing mechanisms? |
| A. | DNA and RNA |
| B. | DNA, RNA and protein |
| C. | Only DNA |
| D. | DNA and proteins |
| Answer» D. DNA and proteins | |
| 37. |
The genome can maintain its essential cellular function even without DNA repair. |
| A. | True |
| B. | False |
| Answer» C. | |
| 38. |
Which of the following mechanisms will remove uracil and incorporate the correct base? |
| A. | Direct repair |
| B. | Base excision repair |
| C. | Mismatch repair |
| D. | Nucleotide excision repair |
| Answer» C. Mismatch repair | |
| 39. |
If the mutation has a negligible effect on the function of a gene, it is known as a |
| A. | Silent mutation |
| B. | Frame shift mutation |
| C. | Substitution mutation |
| D. | Insertion mutation |
| Answer» B. Frame shift mutation | |