Fundamental Processes test

1. Which histone modification is most strongly associated with transcription activation?

2. Double strand breaks are primarily repaired by:

3. Which sequence is recognized during scanning model of eukaryotic initiation?

4. Which polymerase is required for mitochondrial DNA replication?

5. Mutation in SR proteins will affect:

6. A mutation arises due to incorporation of wrong base during replication. Which pathway fixes it immediately?

7. Which order of events is correct?

8. Which statement is true?

9. A cell line lacks telomerase. What phenotype is expected after multiple divisions?

10. A lacI repressor mutant cannot bind operator. Predict operon activity:

11. Which step in 5’ capping is directly dependent on CTD phosphorylation of RNA Pol II?

12. A DNA polymerase mutant has intact 5’→3’ polymerase, lacks 3’→5’ exonuclease, but retains 5’→3’ exonuclease. What happens?

13.

Mutations:

• 5’ GU donor site

• Branch point A

•   3’ AG acceptor

Which outcome is correct?

14.

Cells treated with:

• Tetracycline → blocks A-site tRNA binding

• Chloramphenicol → inhibits peptidyl transferase

• Streptomycin → causes misreading

Polysome profile:

15.

A researcher constructs two mutant promoters:

• Mutant 1: TATA box deleted

• Mutant 2: DPE (downstream promoter element) mutated

• Mutant 3: CTD of RNA Pol II cannot be phosphorylated

Which prediction is correct?

16.

Cells are UV-irradiated to form thymine dimers. Three knockouts:

• XPA (NER)

• DNA ligase

• MSH2 (MMR)

Which result is correct?

17.

An E. coli strain has mutations in three genes:

• dnaA: defective initiation

• dnaQ: defective proofreading

• ligase: defective nick sealing

When tested:

• Mutant A cannot open oriC.

• Mutant B replicates but accumulates point mutations.

• Mutant C accumulates Okazaki fragments.

Which assignment is correct?

18. Match the chemical agents that interfere in oxidative phosphorylation process with their respective mode of action

Choose the correct combination from below:

19. Ciprofloxacin is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class. The target of antibiotic ciprofloxacin is

20. A polypeptide antibiotic isolated from the genus Streptomyces which intercalates into DNA, preventing the progression of RNA polymerase(s) and initiation of DNA replication both prokaryotes and eukaryotes is

21.

• Following statements have been made about removal of supercoiling produced by DNA unwinding at the replication fork:

A. Accumulation of supercoils is the result of DNA helicase activity during unwinding of DNA

B. Problem of DNA supercoiling is valid only for circular chromosomes of bacteria and not for the linear chromosomes

C. Supercoiling of DNA is removed by topoisomerases by breaking either one or both strands of DNA on the unreplicated DNA in front of replication fork.

D. Both topoisomerase I and topoisomerase can remove positive super-coiling during replication

Which one of the following options has all correct statements?

22. Reverse transcriptase of retero virus is-

23. Reproduction of Φ x 174, a single stranded DNA phage involves several steps. A few statements are given below to explain the mechanism.
A. The single stranded Φ X 174 DNA is converted into a double-stranded replicative form (RF)
B. Replication of double stranded replicative form results in the production of single stranded phages, about 50% of which are +ve sense phages and the remaining are -ve sense phages
C. Replication of the double stranded replicative form results in the production of only -ve sense phages
D. Replication of the double stranded replicative form results in the production of only +ve sense phages
Choose the option that correctly describes the process

24. Which post-translational modification marks proteins for degradation via the proteasome pathway?

25. Which of the following is an RNA-dependent RNA polymerase?

26. In eukaryotes, splicing occurs in:

27. The CTD (C-terminal domain) of RNA Pol II is important for:

28. Which of the following enzymes is involved in DNA supercoiling during replication?

29.

Which of the following translation inhibitors specifically binds to the 50S ribosomal subunit?

30. In mismatch repair, the newly synthesized strand is identified in E. coli by:

31. Which of the following is a eukaryotic transcription factor required for promoter clearance of RNA Pol II?

32. The lac operon in E. coli is induced when:

33. Which of the following histone modifications is generally associated with active transcription?

34. In eukaryotes, RNA polymerase III is responsible for synthesis of:

35. The Shine-Dalgarno sequence is recognized by:

36. Which DNA repair mechanism corrects thymine dimers formed by UV irradiation?

37. During DNA replication, Okazaki fragments are synthesized on:

38. In E. coli, which factor helps RNA polymerase to recognize promoter sequences and initiate transcription?

39. Which of the following post-transcriptional modifications occurs only in eukaryotes and not in prokaryotes?

40. The proofreading function of DNA polymerase is carried out by:

41. Which of the following is true for telomerase?

42. Which of the following inhibitors blocks eukaryotic transcription by RNA Pol II?

43. Which of the following proteins is required for mismatch repair (MMR) in humans?

44. In eukaryotic translation initiation, the recognition of start codon AUG requires:

45. The process of splicing of pre-mRNA involves

46. In prokaryotic transcription termination, Rho-dependent termination requires:

47. Which one of the following statements about DNA replication in E. coli is NOT correct?

48. During eukaryotic transcription initiation, which of the following events occurs first?