TRB PG Assistant - Microbial genetics – transformation, conjugation, transduction Online Test (MCQ Quiz)

1. What is the process by which a bacterial cell takes up naked DNA from its environment called?

A) Transduction B) Conjugation C) Transformation D) Replication

2. Which Nobel Prize winners are credited with discovering transformation in bacteria?

A) Watson and Crick B) Griffith and Avery C) Meselson and Stahl D) Hershey and Chase

3. Transformation in bacteria requires the uptake of what type of genetic material?

A) Plasmid DNA B) Viral DNA C) Naked DNA D) Mitochondrial DNA

4. Which mechanism of horizontal gene transfer involves direct cell-to-cell contact?

A) Transformation B) Transduction C) Recombination D) Conjugation

5. In bacterial conjugation, what is the structure that facilitates the transfer of genetic material?

A) Flagellum B) Pilus C) Capsule D) Ribosome

6. What is the term for a plasmid that can integrate into the bacterial chromosome?

A) Episome B) Replicon C) Operon D) Transposon

7. What is the primary role of the F factor in bacterial conjugation?

A) To degrade foreign DNA B) To mediate pilus formation and DNA transfer C) To initiate DNA replication D) To provide antibiotic resistance

8. Which type of gene transfer involves bacteriophages acting as vectors?

A) Transformation B) Conjugation C) Transduction D) Replication

9. What is a bacteriophage?

A) A type of bacteria B) A virus that infects bacteria C) A structure for bacterial movement D) A protein involved in gene expression

10. In transduction, bacterial DNA is transferred from one bacterium to another via:

A) Direct contact B) A pilus C) A bacteriophage D) Environmental DNA uptake

11. What are the two main types of transduction?

A) Lytic and Lysogenic B) Generalized and Specialized C) Positive and Negative D) Direct and Indirect

12. Which type of transduction involves the random packaging of any part of the bacterial genome into a phage head?

A) Specialized Transduction B) Lysogenic Transduction C) Generalized Transduction D) Lytic Transduction

13. Specialized transduction occurs when a prophage excises imprecisely from the bacterial chromosome, carrying adjacent bacterial genes. This is associated with which phage cycle?

A) Lytic cycle B) Lysogenic cycle C) Replication cycle D) Transformation cycle

14. What is a prophage?

A) A free phage particle B) A bacterial cell resistant to phages C) The integrated form of a temperate bacteriophage within the bacterial chromosome D) A specialized structure for DNA transfer

15. Which of the following is NOT a mechanism of horizontal gene transfer in bacteria?

A) Transformation B) Transduction C) Conjugation D) Vertical Gene Transfer

16. Transformation is a natural process in some bacteria but can also be induced artificially in the lab using methods like:

A) Centrifugation and heating B) Electroporation and chemical treatment C) Sonication and irradiation D) Lysozyme treatment and osmotic shock

17. Competence in bacteria refers to:

A) The ability to form biofilms B) The ability to take up foreign DNA C) The ability to move using flagella D) The ability to produce toxins

18. Conjugation typically requires a donor cell with a plasmid that carries genes for:

A) Ribosome synthesis B) Cell wall formation C) Pilus formation and DNA transfer D) Photosynthesis

19. What is the term for a bacterium that has received foreign DNA through transformation, conjugation, or transduction?

A) Wild-type B) Recombinant C) Auxotroph D) Prototroph

20. Bacterial conjugation can lead to the spread of antibiotic resistance genes because these genes are often located on:

A) The bacterial chromosome only B) Plasmids C) Ribosomes D) The cell wall

21. Generalized transduction can be used to transfer genes that are:

A) Located only near the origin of replication B) Located anywhere on the bacterial chromosome C) Located only on plasmids D) Located only in the operon

22. Specialized transduction is limited to transferring genes that are:

A) Randomly distributed on the chromosome B) Located near the integration site of the prophage C) Located on plasmids D) Essential for phage replication

23. The bacterium Streptococcus pneumoniae is naturally competent, meaning it can readily undergo:

A) Conjugation B) Transduction C) Transformation D) Binary Fission

24. Hfr (High frequency of recombination) cells are formed when:

A) A plasmid is lost from the cell B) The F factor integrates into the bacterial chromosome C) A bacteriophage infects the cell D) The cell undergoes transformation

25. During conjugation involving Hfr cells, what is typically transferred to the recipient cell?

A) The entire F factor B) A portion of the bacterial chromosome C) Only the pilus D) A complete F plasmid

26. What is the term for a bacteriophage that can integrate into the bacterial genome and replicate with it?

A) Lytic phage B) Temperate phage C) Virulent phage D) Filamentous phage

27. The discovery of transformation by Frederick Griffith in 1928 used which organism?

A) Escherichia coli B) Bacillus subtilis C) Streptococcus pneumoniae D) Staphylococcus aureus

28. Which of the following is a key difference between transformation and transduction?

A) Transformation involves plasmids, transduction involves bacteriophages. B) Transformation requires direct cell contact, transduction does not. C) Transformation uses naked DNA, transduction uses DNA carried by a phage. D) Transformation is always artificial, transduction is always natural.

29. Bacterial conjugation can be mediated by plasmids that are:

A) Extrachromosomal DNA molecules B) Integrated into the chromosome C) Part of the ribosome structure D) Involved in cell wall synthesis

30. What is the primary function of the genes encoded by the F factor in conjugation?

A) Metabolic pathways B) Antibiotic resistance C) Pilus synthesis and DNA transfer machinery D) Cell division

31. A bacteriophage that exclusively follows the lytic cycle is termed:

A) Temperate B) Lysogenic C) Virulent D) Avirulent

32. The process of generalized transduction allows for the transfer of:

A) Specific genes only B) Any bacterial gene C) Only genes located on plasmids D) Only genes near the origin of replication

33. Which mechanism of gene transfer is most efficient for transferring large segments of the bacterial chromosome?

A) Transformation B) Specialized Transduction C) Conjugation (especially Hfr) D) Generalized Transduction

34. The ability of a bacterial cell to accept and integrate foreign DNA through transformation depends on the presence of:

A) A pilus B) A temperate phage C) Specific uptake systems and competence factors D) A conjugation plasmid

35. During transduction, the DNA fragment transferred to the recipient cell originates from:

A) The phage genome B) The donor bacterium's chromosome or plasmid C) The recipient bacterium's chromosome D) A plasmid in the phage

36. What is the term for a bacterial cell that is capable of accepting DNA during transformation?

A) Donor cell B) Recipient cell C) Competent cell D) Hfr cell

37. What is the role of the pilus in bacterial conjugation?

A) To degrade foreign DNA B) To attach to the recipient cell and initiate DNA transfer C) To replicate the donor's DNA D) To provide energy for the process

38. Which type of transduction is characterized by the transfer of specific bacterial genes that are located adjacent to the prophage integration site?

A) Generalized Transduction B) Lytic Transduction C) Specialized Transduction D) Virulent Transduction

39. The discovery of the genetic role of DNA by Avery, MacLeod, and McCarty in 1944 provided strong evidence for:

A) The mechanism of conjugation B) The transforming principle C) The structure of the pilus D) The process of transduction

40. What is the main difference between the F+ and F- bacterial states in conjugation?

A) F+ cells have the F factor, F- cells do not. B) F+ cells can only receive DNA, F- cells can only donate. C) F+ cells are always integrated into the chromosome, F- cells are not. D) F+ cells are resistant to phages, F- cells are not.

41. Which of the following is a limitation of transformation as a method of gene transfer?

A) It requires a bacteriophage. B) It can only transfer genes from closely related species. C) The efficiency can be low, and only certain bacteria are naturally competent. D) It requires direct cell-to-cell contact.

42. The process where a virus injects its genetic material into a bacterium is called:

A) Transformation B) Conjugation C) Transduction D) Transfection

43. When a bacteriophage infects a bacterium and integrates its DNA into the host chromosome, it is in the:

A) Lytic cycle B) Replication cycle C) Lysogenic cycle D) Transformation cycle

44. What is the term for a bacterial cell that has acquired new genetic traits through horizontal gene transfer?

A) Protogenote B) Parental cell C) Recombinant cell D) Wild-type cell

45. Which of these processes allows for the transfer of genetic material between bacteria that are not necessarily closely related?

A) Binary fission B) Vertical gene transfer C) Horizontal gene transfer (transformation, conjugation, transduction) D) DNA replication

46. The 'jumping genes' or transposons can move between plasmids and chromosomes, and can be transferred via conjugation, potentially influencing genetic variation.

A) True, as transposons are mobile genetic elements transferred during conjugation. B) False, transposons are fixed genetic elements. C) True, but only during transformation. D) False, transposons are only found in eukaryotes.

47. In specialized transduction, the bacterial genes transferred are typically those that are:

A) Located randomly on the chromosome. B) Adjacent to the integrated prophage DNA. C) Part of the F plasmid. D) Essential for the lytic cycle.

48. What is the primary advantage of horizontal gene transfer for bacteria?

A) Faster reproduction rate B) Increased genetic diversity and adaptation C) Improved cell wall structure D) Enhanced flagellar motility

49. The F factor in conjugation carries genes essential for pilus formation and DNA transfer, making it a key determinant of the process.

A) True, the F factor encodes the machinery for conjugation. B) False, conjugation is mediated by the bacterial chromosome. C) True, but only in specialized transduction. D) False, the pilus is formed by the recipient cell.

Microbial genetics – transformation, conjugation, transduction - Online Test

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