Class 12/Question Bank/Competency Based
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
BioNotesBioNotesCreated by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Competency Based Questions on Principles of Biotechnology
1. Analyze the Process: A student is performing a PCR reaction. After 30 cycles, he observes no amplification of the target gene. Upon checking the protocol, he finds he used human DNA polymerase instead of Taq polymerase. Why did the reaction fail? a) Human polymerase cannot add nucleotides. b) Human polymerase is not thermostable and denatures at 94°C during the denaturation step. c) Human polymerase requires a different pH. d) Primers do not bind to human polymerase.
2. Evaluate the Cloning Strategy: You want to clone a human gene into E. coli. The gene contains introns. Which of the following should you use as the starting material to ensure the bacteria produces the correct protein? a) Genomic DNA b) mRNA c) cDNA (Complementary DNA made from mRNA) d) tRNA
3. Predict the Result: In Blue-White screening, a researcher inserts a gene of interest successfully into the lacZ gene of a plasmid vector. When these bacteria are plated on X-gal medium, the colonies will appear: a) Blue, because the enzyme is active. b) White, because the enzyme is inactivated (Insertional Inactivation). c) Blue, because the gene enhances enzyme activity. d) Colorless/Transparent because the bacteria die.
4. Assertion (A): Restriction endonucleases are called "molecular scissors". Reason (R): They cut DNA at random locations to generate fragments. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
5. Bioprocess Control: In a stirred-tank bioreactor, the "sparger" system malfunctions. Which parameter will be most immediately and critically affected? a) Temperature b) pH c) Dissolved Oxygen availability d) Foam level
6. Identify the Enzyme: Which enzyme is essential for joining the "sticky ends" of a vector and a foreign gene to form a recombinant DNA molecule? a) DNA Polymerase b) Exonuclease c) DNA Ligase d) Alkaline Phosphatase
7. Transformation Logic: Why are bacterial cells treated with Calcium Chloride () before transformation? a) To kill the bacteria. b) To make the cell wall permeable to DNA (Competence). c) To provide nutrients for the DNA. d) To activate the restriction enzymes.
8. Analyze the Gel: In agarose gel electrophoresis, DNA fragments separate based on size. Where would you find the smallest DNA fragments? a) Near the cathode (negative electrode) where DNA was loaded. b) Near the anode (positive electrode), furthest from the well. c) In the middle of the gel. d) DNA does not move in an electric field.
9. Selectable Marker: A plasmid vector has two antibiotic resistance genes: Ampicillin () and Tetracycline (). A foreign gene is inserted into the site. A recombinant colony will be: a) Resistant to both Ampicillin and Tetracycline. b) Sensitive to both. c) Resistant to Ampicillin but sensitive to Tetracycline. d) Resistant to Tetracycline but sensitive to Ampicillin.
10. Downstream Processing: Which of the following is not a part of downstream processing? a) Separation of the product. b) Purification of the product. c) Genetic engineering of the host cell. d) Clinical trials (quality control).
11. PCR Components: If you forget to add "Primers" to your PCR mixture, what will happen? a) Non-specific amplification will occur. b) No new DNA strands will be synthesized. c) The DNA will not denature. d) Taq polymerase will degrade the template.
12. Vector Choice: Which vector would be most suitable for transferring a gene into a plant cell? a) pBR322 b) Retrovirus c) Ti plasmid (Agrobacterium) d) Lambda Phage
13. Palindromic Sequence: Which of the following sequences is a palindrome (read same 5'->3' on both strands)? a) 5'-G A A T T C-3' b) 5'-C C T A G G-3' c) 5'-A T G C T G-3' d) 5'-A G C T-3'
14. Process Sequence: Correct order of rDNA steps: a) Isolation -> Ligation -> Cutting -> Transformation. b) Cutting -> Isolation -> Transformation -> Ligation. c) Isolation -> Cutting -> Ligation -> Transformation. d) Transformation -> Cutting -> Ligation -> Isolation.
15. Critical Thinking: Why is ethidium bromide used in gel electrophoresis? a) To cut the DNA. b) To visualize DNA under UV light (it intercalates). c) To make the DNA heavier. d) To give a negative charge to DNA.
A biotech company wants to produce human insulin on a large scale. They isolate the human insulin gene. Scenario A: They insert the gene directly into a bacterial genome without a vector. Scenario B: They insert the gene into a high-copy-number plasmid vector and transform E. coli.
16. Evaluate: Which scenario is likely to produce insulin? a) Scenario A only. b) Scenario B only. c) Both. d) Neither.
17. Reasoning: Why does Scenario A fail? a) Bacteria degrade human DNA instantly. b) The DNA cannot replicate because it lacks an "Origin of Replication" (ori) which the vector provides. c) The gene is too large. d) Bacteria don't have insulin receptors.
18. Optimization: To maximize production in Scenario B, the company uses a Stirred-tank Bioreactor. What is the specific role of the "Stirrer"? a) To cut the DNA. b) To maintain even temperature and oxygen availability throughout the tank. c) To kill unwanted bacteria. d) To precipitate the insulin.
A student creates a recombinant plasmid by inserting gene X into the BamHI site of the pBR322 vector. The BamHI site is located within the Tetracycline resistance gene (). The vector also has an Ampicillin resistance gene ().
19. Predict: What will be the phenotype of the transformants containing the recombinant plasmid? a) b) c) d)
20. Method: How will the student select these recombinant bacteria from non-recombinants? a) They will grow on Tetracycline plates. b) They will grow on Ampicillin plates but die on Tetracycline plates (Replica Plating). c) They will be blue in color. d) They will be fluorescent.
21. Troubleshooting: If the student finds colonies growing on both Ampicillin and Tetracycline plates, what does this indicate? a) The ligation was successful. b) The ligation failed, and the plasmid re-circularized without the gene (Non-recombinant). c) The bacteria mutated. d) Gene X confers tetracycline resistance.
Investigators find a tiny drop of blood at a crime scene. The amount of DNA is too small for standard fingerprinting.
22. Strategy: Which technique must be used first to make the sample usable? a) Gel Electrophoresis. b) PCR (Polymerase Chain Reaction). c) Southern Blotting. d) Centrifugation.
23. Process: During this technique, the temperature is raised to 94°C. What happens to the DNA at this step? a) It replicates. b) It denatures (strands separate). c) Primers anneal. d) It gets cut by restriction enzymes.
24. Enzyme: Why is the enzyme from Thermus aquaticus used in this specific process? a) It is faster than human enzymes. b) It is thermostable and survives the 94°C heating step. c) It proofs-read errors. d) It works at 0°C.
25. Designing a Vector: You need to design a new cloning vector for yeast.
26. Troubleshooting a Bioreactor: Problem: The cell growth in your bioreactor has suddenly stopped, and the pH has dropped significantly.
27. Analogy Creation: Create a real-world analogy for Recombinant DNA Technology.
28. Ethical Evaluation: "Biopiracy" involves using bio-resources of a country without authorization.
29. Visualizing the Process: Draw a schematic of Agarose Gel Electrophoresis.
30. Formulating a Hypothesis: Observation: Restriction enzymes in bacteria cut foreign viral DNA but do not cut the bacteria's own DNA, even though the recognition sequences might be present.
31. Critical Comparison: Compare PCR inside a test tube vs. DNA Replication inside a living cell.