Biotechnology: Principles and Processes Mock Test – Class 12 Biology

1. A graph from an agarose-gel experiment has DNA fragment size on the horizontal axis and relative migration distance from the loading well on the vertical axis. Under otherwise comparable electrophoretic conditions, which qualitative trend should the graph show?

2. Two laboratories work with the same microorganism. Laboratory P changes its genetic material before introducing it into a host strain. Laboratory Q grows a selected strain under carefully controlled sterile conditions to manufacture a biological product. The major techniques emphasised by P and Q, respectively, are

3. Two production cultures contain the same recombinant organism:

Which relationship is best supported?

4. In a bacterial restriction-modification system, two DNA molecules contain the same recognition sequence. Molecule P carries the protective modification characteristic of the host, whereas molecule Q lacks that modification. If the corresponding restriction enzyme is active, which outcome is most consistent with the system?

5. A microorganism has already been engineered to carry a desired gene. It produces the required product in a small sterile flask, but an industrial batch repeatedly fails because the large culture becomes contaminated. Which intervention addresses the unresolved biotechnology problem most directly?

6. A cloning vector contains a functional β-galactosidase coding sequence with a cloning site located within that sequence. What is the expected effect if foreign DNA is successfully inserted at the cloning site?

7. A cloned gene has been successfully introduced into a suitable host and is being expressed. At laboratory scale, the desired recombinant protein can subsequently be

8. A proposed cloning vector has a functional ori and antibiotic-resistance marker. However, the chosen restriction enzyme cuts at six sites scattered throughout the plasmid. Which redesign would most directly improve cloning predictability?

9. After cloning foreign DNA at the BamHI site within tetR of pBR322, a plasmid-bearing colony shows the phenotype ampR tetS. Which molecular interpretation best explains this pattern?

10. Agrobacterium tumefaciens is useful in biotechnology because its natural biology demonstrates an ability to

11. A bacterial cell contains many copies of a cloned foreign gene, but no detectable protein encoded by that gene is produced. Which conclusion is most appropriate?

12. Assertion: Loss of tetracycline resistance can indicate successful insertion of foreign DNA into the BamHI site of tetR in pBR322.
Reason: Insertion of foreign DNA within a functional marker gene can interrupt expression of that marker.

13. Two samples contain the same type of protein. Sample P was produced naturally by the original organism without recombinant-DNA manipulation. Sample Q was produced by a different host after a cloned gene from the original organism was introduced and expressed. Which statement is correct?

14. A plasmid carries both an antibiotic-resistance marker and a β-galactosidase screening region. After antibiotic selection, all surviving colonies are known to be transformants. Why can the subsequent colour test provide additional information?

15. A harvested culture contains the target protein together with cells and numerous unwanted molecules. After one operation, the target protein is recovered into a separate fraction but still contains several contaminants. Which distinction is most appropriate?

16. A recombinant therapeutic drug has completed appropriate clinical evaluation, but final quality-control testing of the current manufactured lot detects an unacceptable contaminant. Which conclusion is most appropriate?

17. A DNA preparation still contains substantial RNA and protein when chilled ethanol is added. Fine thread-like material precipitates and can be wound onto a glass rod. Which conclusion is most appropriate?

18. Vector DNA and foreign DNA both contain the EcoRI recognition site and are cut with EcoRI. Which sequence of events best explains how this promotes recombinant formation?

19. A stirred-tank bioreactor includes both a sterile-air inlet and a steam-sterilisation arrangement. Which distinction between these two features is correct?

20. A competent bacterial population receives recombinant plasmid DNA carrying ampR. After transformation, the cells are plated on ampicillin-containing medium. Colonies appear only at some positions. What can be concluded most directly about the surviving colonies?

21. In one lane of an agarose gel, fragment P travels twice as far from the well as fragment Q during the same electrophoresis run. What is the safest conclusion based on the principles of agarose gel electrophoresis?

22. Consider the following statements about bacterial restriction-modification systems:
I. Modification can involve methylation of specific DNA sequences.
II. Restriction endonucleases cut DNA.
III. Methylation and restriction represent exactly the same enzymatic activity.
IV. The system provides a conceptual basis for sequence-specific DNA discrimination.
Which option is correct?

23. In a bacterial restriction-modification system, the host's recognition sites are appropriately protected, but the modification activity is experimentally lost while the restriction endonuclease remains active. Which prediction is most reasonable?

24. Assertion: A thermostable DNA polymerase is particularly suitable for PCR.
Reason: PCR repeatedly includes a high-temperature DNA-denaturation stage that would inactivate many ordinary enzymes.

25. A stirred-tank bioreactor is commonly designed with a cylindrical body and a curved base. An important functional advantage of stirring in such a system is to

26. A recombinant plasmid carrying a foreign DNA insert is initially maintained normally in a bacterial population. A mutation later makes its origin of replication non-functional, while the selectable marker and insert remain physically intact. If no alternative replication mechanism is available, what is the most likely long-term outcome during repeated cell division?

27. A plasmid contains a foreign gene and enters a bacterial cell successfully. The selectable marker is functional, so the cell survives antibiotic treatment, but the plasmid is gradually lost from descendants. Which vector feature is the strongest candidate for the defect?

28. A researcher mistakenly interprets every blue colony in a β-galactosidase insertional-inactivation experiment as recombinant. Why is this interpretation incorrect?

29. A cloning experiment uses one restriction enzyme to cut the desired source DNA and a second enzyme to open the vector. The two enzymes generate overhangs that cannot base-pair with each other. What is the most likely result?

30. Two PCR reactions use the same template DNA:

Which conclusion is best supported?

31. Two PCR reactions contain the same primer pair, free nucleotides and thermostable DNA polymerase and are subjected to the same correctly programmed thermal cycles. Reaction P also contains the target DNA template, whereas reaction Q contains no template DNA. P produces the expected amplification product but Q does not. Which inference best isolates the role of the missing component?

32. Biotechnology, in its broad sense, is best described as the use of

33. Two transformed bacterial colonies carry pBR322-derived plasmids:

The cloning experiment inserted foreign DNA at the BamHI site within tetR. Which interpretation is most appropriate?

34. The plasmid pBR322 contains several functionally important regions. Match the feature with its most appropriate description.

35. Four observations are obtained from different stages of one recombinant-protein project:

Which sequence represents increasing progression through the production pathway?

36. Four DNA-isolation preparations show the following results:

Which preparation most strongly indicates successful ribonuclease treatment, successful protease treatment and effective DNA precipitation?

37. In a successful sticky-end cloning reaction, complementary vector and insert ends have already paired. What additional molecular event is required to make the recombinant DNA structurally stable?

38. Consider the following statements about a bioreactor:
I. It supports biological conversion of raw materials into desired products.
II. It may contain microbial, plant, animal or human cells.
III. Its operation depends on maintaining appropriate environmental conditions.
IV. Its principal function is to separate DNA fragments according to size.
Which option is correct?

39. During agarose gel electrophoresis, DNA fragments migrate toward the positive electrode primarily because DNA

40. In the restriction-enzyme name EcoRI, which part most directly represents the bacterial strain designation?

41. A production vessel begins developing heavy foam while pH, temperature and oxygen readings remain within their intended ranges. Which response most directly addresses the observed process problem?

42. Samples from a bioreactor are withdrawn every hour. The sampling data show stable pH and temperature but a progressive fall in dissolved oxygen followed by a decline in product formation. Which interpretation is most reasonable?

43. A PCR reaction produces a large quantity of the desired DNA segment. The amplified DNA is then introduced directly into bacterial culture without first being joined to a replicating vector. Which limitation remains most important if long-term intracellular maintenance is required?

44. Disarmed Ti-plasmid vectors and disarmed retroviral vectors are adapted from very different natural systems. What engineering principle do they share?

45. In a β-galactosidase insertional-inactivation system, antibiotic selection produces plasmid-bearing colonies. Of these, are non-coloured and are blue under the stated chromogenic conditions. Which conclusion is most appropriate?

46. Which statement best distinguishes competence-mediated bacterial transformation, micro-injection and disarmed-vector delivery?

47. A target protein has been synthesised inside recombinant cells, but most of it remains mixed with cellular material and culture-medium components. Which operation belongs immediately to the post-biosynthetic phase?

48. Source DNA and vector DNA are both cut with the same suitable restriction enzyme, producing complementary sticky ends. Before ligase is added, what molecular event is most likely to occur?

49. A product has been separated from most of the culture material but still contains several unwanted molecules at concentrations unacceptable for final use. Which downstream objective remains incomplete?

50. In the restriction enzyme name EcoRI, the Roman numeral I indicates