A. Standard / Conceptual MCQs – Biotechnology (50 MCQs)

1. Principles of Biotechnology & Recombinant DNA

Q1. Recombinant DNA is formed by:
A. Combining DNA from two different sources
B. Mutating bacterial DNA
C. Using RNA polymerase only
D. Protein synthesis

Q2. Gene cloning requires:
A. Vector and restriction enzymes
B. Only DNA ligase
C. PCR without vector
D. Antibodies

Q3. A plasmid is used as a:
A. Vector for gene cloning
B. Microbial pathogen
C. Antibiotic
D. Restriction enzyme

Q4. Restriction enzymes cut DNA at:
A. Specific palindromic sequences
B. Random sites
C. Only at promoters
D. Ribosome-binding sites

Q5. DNA ligase is used to:
A. Join DNA fragments
B. Cut DNA
C. Amplify DNA
D. Transcribe DNA

Q6. cDNA is synthesized using:
A. Reverse transcriptase
B. DNA polymerase
C. RNA polymerase
D. Ligase

Q7. Sticky ends are:
A. Overhanging single-stranded DNA generated by restriction enzymes
B. Double-stranded DNA
C. RNA fragments
D. Protein tags

Q8. A vector must have:
A. Origin of replication and selectable marker
B. Only antibiotic resistance
C. Only promoter
D. Only enhancer

Q9. Gene cloning is used for:
A. Producing insulin, vaccines, or enzymes
B. Killing bacteria
C. Producing antibiotics only
D. Food fermentation

Q10. Recombinant DNA technology allows:
A. Insertion of foreign genes into host genome
B. Random mutations
C. Only DNA repair
D. Protein synthesis

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2. Tools & Techniques in Biotechnology

Q11. Agarose gel electrophoresis separates DNA based on:
A. Size and charge
B. Sequence only
C. Function
D. Protein content

Q12. Southern blotting detects:
A. Specific DNA sequences
B. RNA only
C. Proteins only
D. Lipids

Q13. Northern blotting is used for:
A. Detecting RNA sequences
B. Detecting DNA sequences
C. Protein detection
D. Microbial identification

Q14. PCR is used to:
A. Amplify DNA fragments
B. Cut DNA
C. Ligate DNA
D. Transform bacteria

Q15. Taq polymerase is used in PCR because:
A. It is heat-stable
B. It cuts DNA
C. It ligates DNA
D. It digests RNA

Q16. Restriction enzymes are naturally found in:
A. Bacteria
B. Viruses
C. Plants
D. Fungi

Q17. Plasmid vectors often carry:
A. Antibiotic resistance genes for selection
B. Only promoters
C. Only enhancers
D. Ribosomes

Q18. Gene probes are labeled DNA/RNA sequences used for:
A. Detecting complementary nucleic acid sequences
B. Amplifying DNA
C. Transforming host
D. Producing enzymes

Q19. DNA fingerprinting uses:
A. Variable number tandem repeats (VNTRs)
B. rRNA sequences only
C. Plasmids only
D. Protein markers

Q20. Blunt-end DNA fragments are:
A. Even-ended, no overhangs
B. Single-stranded overhangs
C. RNA fragments
D. Sticky ends

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3. Processes – Gene Manipulation

Q21. cDNA is preferred over genomic DNA for cloning because:
A. It lacks introns
B. It is double-stranded
C. It contains promoters
D. It has enhancers

Q22. Restriction digestion is followed by:
A. Ligation
B. PCR only
C. Transformation only
D. Southern blotting

Q23. Transformation refers to:
A. Uptake of foreign DNA by a host cell
B. DNA replication
C. Protein translation
D. RNA splicing

Q24. A host for recombinant DNA should be:
A. Easy to grow and non-pathogenic
B. Pathogenic
C. Slow-growing
D. Only eukaryotic

Q25. Expression vectors contain:
A. Promoters to drive gene transcription
B. Only replication origin
C. Restriction sites only
D. None of the above

Q26. Marker genes in vectors help to:
A. Identify transformed cells
B. Digest DNA
C. Amplify RNA
D. Cut plasmids

Q27. Gel electrophoresis buffer provides:
A. Conductivity and maintains pH
B. Heat
C. Enzymes
D. Selective markers

Q28. Southern blot involves:
A. DNA transfer from gel to membrane for hybridization
B. Protein detection
C. RNA detection
D. Gel staining only

Q29. Reverse transcriptase is obtained from:
A. Retroviruses
B. Bacteria
C. Yeast
D. Plasmids

Q30. Gene libraries are collections of:
A. DNA fragments representing the whole genome
B. Proteins only
C. RNA sequences
D. Enzymes

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4. Applications of Biotechnology

Q31. Recombinant insulin is produced in:
A. E. coli
B. Yeast only
C. Bacillus subtilis
D. Streptomyces

Q32. Bt cotton contains:
A. Cry gene from Bacillus thuringiensis
B. Nitrogen-fixing genes
C. Antibiotic genes
D. Yeast genes

Q33. Golden rice is engineered to produce:
A. Beta-carotene (Vitamin A precursor)
B. Vitamin B12
C. Insulin
D. Citric acid

Q34. Gene therapy involves:
A. Insertion of functional genes to correct genetic disorders
B. Producing antibiotics
C. DNA fingerprinting
D. Gel electrophoresis

Q35. Microbial enzymes in industry include:
A. Amylase, protease, lipase
B. Hemoglobin only
C. DNA polymerase only
D. Taq ligase only

Q36. PCR is widely used in:
A. DNA diagnostics and forensic studies
B. Producing alcohol
C. Biogas production
D. Biodegradation

Q37. Bioreactors are used for:
A. Large-scale production of microbial products
B. DNA extraction only
C. Gel electrophoresis
D. Southern blotting

Q38. Genetically modified microbes can produce:
A. Insulin, vaccines, enzymes, and antibiotics
B. Only alcohol
C. Only citric acid
D. Only vitamins

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5. Ethics & Biosafety

Q39. Recombinant DNA experiments follow:
A. Biosafety guidelines to prevent contamination and risk
B. No regulation
C. Only local rules
D. Only ethical review

Q40. GM crops are regulated because:
A. Potential environmental and health effects
B. They produce toxins in humans
C. They cannot grow
D. They do not yield food

Q41. Microbes used in biotechnology should ideally be:
A. Non-pathogenic
B. Pathogenic for efficiency
C. Rare only
D. Slow-growing

Q42. Containment in biotechnology labs prevents:
A. Accidental release of recombinant organisms
B. PCR failure
C. Gel electrophoresis errors
D. Digestion errors

Q43. Gene therapy raises ethical concerns because:
A. It involves human genome modification
B. It produces enzymes
C. It produces insulin
D. It uses bacteria

Q44. GMOs in agriculture require:
A. Regulatory approvals before field release
B. Only lab experiments
C. No regulation
D. Only farmer consent

Q45. Antibiotic resistance genes in vectors are carefully managed to:
A. Prevent horizontal gene transfer to pathogens
B. Enhance bacterial growth
C. Produce enzymes
D. Increase yield

A. Assertion–Reason MCQs – Biotechnology (15 MCQs)

Q1.
Assertion: Restriction enzymes cut DNA at specific sequences.
Reason: Sticky ends facilitate joining of DNA fragments.

Q2.
Assertion: DNA ligase is essential in recombinant DNA technology.
Reason: It joins DNA fragments to form a complete DNA molecule.

Q3.
Assertion: cDNA is preferred for cloning eukaryotic genes in bacteria.
Reason: cDNA lacks introns, making it expressible in prokaryotes.

Q4.
Assertion: Plasmid vectors carry antibiotic resistance genes.
Reason: Antibiotic resistance allows selection of transformed cells.

Q5.
Assertion: PCR requires Taq polymerase.
Reason: Taq polymerase is heat-stable and can withstand repeated heating cycles.

Q6.
Assertion: Southern blotting detects specific DNA sequences.
Reason: Labeled DNA probes hybridize to complementary sequences.

Q7.
Assertion: Northern blotting is used to study gene expression.
Reason: RNA is transferred from gel to membrane and probed with complementary sequences.

Q8.
Assertion: Bt cotton expresses the Cry protein.
Reason: Cry protein acts as an insecticide against pests.

Q9.
Assertion: Gene therapy can treat genetic disorders.
Reason: Functional genes are inserted into the patient’s genome.

Q10.
Assertion: Bioreactors allow large-scale microbial production.
Reason: Controlled conditions optimize growth and product yield.

Q11.
Assertion: Golden rice is genetically modified to produce beta-carotene.
Reason: Beta-carotene is a precursor of Vitamin A.

Q12.
Assertion: Expression vectors contain promoters.
Reason: Promoters drive transcription of cloned genes.

Q13.
Assertion: Taq polymerase is obtained from thermophilic bacteria.
Reason: Thermostability allows repeated PCR cycles without enzyme denaturation.

Q14.
Assertion: Gene libraries represent all DNA fragments of an organism.
Reason: Libraries allow isolation of individual genes for cloning or study.

Q15.
Assertion: Recombinant DNA experiments require biosafety measures.
Reason: Prevents accidental release of genetically modified organisms.

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B. Difficult / Case-Based MCQs – Biotechnology (15 MCQs)

Q16. A lab wants to produce human insulin using bacteria. Which steps are essential?
A. Insert human insulin gene into plasmid, transform E. coli, select transformed cells
B. Direct injection of human DNA into patient
C. Ferment milk with bacteria
D. Use only PCR

Q17. A scientist wants to amplify a small DNA fragment. Which technique is most appropriate?
A. PCR
B. Southern blot
C. Northern blot
D. Gene therapy

Q18. A plasmid vector contains lacZ gene and antibiotic resistance. Purpose of lacZ:
A. Blue-white screening to identify recombinant clones
B. Antibiotic production
C. Fermentation
D. DNA amplification

Q19. A patient requires correction of a defective gene. Best approach:
A. Gene therapy
B. Southern blot
C. PCR only
D. Microbial fermentation

Q20. In Bt cotton, which gene provides pest resistance?
A. Cry gene from Bacillus thuringiensis
B. Insulin gene
C. Beta-carotene gene
D. Antibiotic resistance gene

Q21. DNA fragment is inserted into plasmid and transformed into bacteria. How are successful transformants identified?
A. Antibiotic selection
B. Gel electrophoresis only
C. PCR only
D. DNA fingerprinting

Q22. A biotech lab wants to study mRNA expression of a gene. Which method?
A. Northern blotting
B. Southern blotting
C. PCR
D. Gene cloning

Q23. Which is correct sequence of recombinant DNA steps?
A. Restriction digestion → Ligation → Transformation → Selection
B. Transformation → Ligation → Restriction digestion
C. PCR → Ligation → Selection
D. Southern blot → Transformation → Ligation

Q24. A forensic lab needs to identify an individual using DNA. Which technique?
A. DNA fingerprinting / VNTR analysis
B. PCR only
C. Southern blot only
D. Bt gene expression

Q25. Bioreactor designed for enzyme production should control:
A. pH, temperature, aeration, nutrient supply
B. Only temperature
C. Only pH
D. Only oxygen

Q26. cDNA is synthesized from RNA for cloning in E. coli. Why?
A. Removes introns that cannot be processed by bacteria
B. Adds promoter sequences
C. Cuts DNA into fragments
D. Produces antibiotics

Q27. Which of the following is true about gene probes?
A. They are labeled nucleic acids complementary to target DNA/RNA
B. They amplify DNA
C. They cut DNA fragments
D. They produce proteins

Q28. Southern blot shows hybridization signal on a membrane. Interpretation:
A. Target DNA fragment is present
B. Target RNA fragment is absent
C. Protein is detected
D. Gene therapy successful

Q29. A lab wants to produce citric acid industrially using a microbe. Which is correct?
A. Aspergillus niger is used under controlled fermentation
B. E. coli is used
C. Bt is used
D. Yeast only

Q30. A GMO crop is released in the field. Which regulation is necessary?
A. Biosafety and environmental risk assessment
B. No regulation needed
C. Only lab observation
D. Only farmer consent

Biotechnology: Principles and Processes – Answer Key with Explanations (Q1–75)

Q.No	Answer	Explanation
1	A	Recombinant DNA combines DNA from two sources using restriction enzymes and ligase.
2	A	Gene cloning requires a vector (plasmid) and restriction enzymes.
3	A	Plasmids act as vectors to carry foreign DNA into host cells.
4	A	Restriction enzymes cut DNA at specific palindromic sequences.
5	A	DNA ligase joins DNA fragments to form recombinant molecules.
6	A	Reverse transcriptase synthesizes cDNA from RNA.
7	A	Sticky ends are single-stranded overhangs that facilitate ligation.
8	A	Vectors need an origin of replication and selectable markers.
9	A	Gene cloning produces insulin, vaccines, and enzymes.
10	A	Recombinant DNA allows insertion of foreign genes into hosts.
11	A	Agarose gel separates DNA by size and charge under electric field.
12	A	Southern blot detects specific DNA sequences using labeled probes.
13	A	Northern blot detects RNA sequences using complementary probes.
14	A	PCR amplifies DNA fragments exponentially.
15	A	Taq polymerase is heat-stable, essential for PCR.
16	A	Restriction enzymes are naturally produced by bacteria as a defense.
17	A	Plasmids often carry antibiotic resistance genes to select transformants.
18	A	Gene probes hybridize to complementary nucleic acid sequences.
19	A	DNA fingerprinting uses VNTRs to identify individuals.
20	A	Blunt-end DNA fragments have no overhangs, unlike sticky ends.
21	A	cDNA lacks introns, making it suitable for cloning in prokaryotes.
22	A	Restriction digestion is followed by ligation to form recombinant DNA.
23	A	Transformation is uptake of foreign DNA by host cells.
24	A	Host cells must be easy to grow and non-pathogenic.
25	A	Expression vectors have promoters to drive transcription of foreign genes.
26	A	Marker genes identify successfully transformed cells.
27	A	Electrophoresis buffer conducts electricity and maintains pH.
28	A	Southern blot transfers DNA from gel to membrane for hybridization.
29	A	Reverse transcriptase is derived from retroviruses.
30	A	Gene libraries are collections of DNA fragments representing the genome.
31	A	Recombinant insulin is produced in E. coli by inserting human insulin gene.
32	A	Bt cotton expresses Cry proteins from Bacillus thuringiensis to kill pests.
33	A	Golden rice is genetically engineered to produce beta-carotene.
34	A	Gene therapy inserts functional genes to correct defective genes.
35	A	Industrial microbes produce enzymes like amylase, protease, lipase.
36	A	PCR is widely used for DNA diagnostics and forensic applications.
37	A	Bioreactors allow large-scale microbial production of products.
38	A	Recombinant microbes can produce insulin, enzymes, vaccines, antibiotics.
39	A	Recombinant DNA experiments follow biosafety guidelines.
40	A	GM crops are regulated for environmental and health safety.
41	A	Non-pathogenic microbes reduce risk in biotech applications.
42	A	Containment prevents accidental release of recombinant organisms.
43	A	Gene therapy involves ethical concerns due to genome modification.
44	A	GMOs require regulatory approval before field release.
45	A	Antibiotic resistance genes are managed to prevent horizontal transfer.

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Assertion–Reason MCQs – Answers + Explanations (Q46–Q60)

Q.No	Answer	Explanation
46	A	Restriction enzymes cut DNA; sticky ends allow joining of DNA fragments.
47	A	DNA ligase joins fragments, essential for recombinant DNA formation.
48	A	cDNA lacks introns, allowing expression in bacteria.
49	A	Plasmid vectors carry antibiotic resistance genes to identify transformed cells.
50	A	PCR requires Taq polymerase for repeated heating cycles.
51	A	Southern blot uses labeled probes to detect specific DNA.
52	A	Northern blot transfers RNA to membrane for hybridization.
53	A	Bt cotton expresses Cry proteins acting as insecticide.
54	A	Gene therapy inserts functional genes to correct genetic defects.
55	A	Bioreactors provide controlled environment for microbial production.
56	A	Golden rice produces beta-carotene, precursor of Vitamin A.
57	A	Expression vectors need promoters to drive transcription.
58	A	Taq polymerase is heat-stable, suitable for PCR cycles.
59	A	Gene libraries allow isolation and study of individual genes.
60	A	Biosafety measures prevent accidental release of GMOs.

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Difficult / Case-Based MCQs – Answers + Explanations (Q61–Q75)

Q.No	Answer	Explanation
61	A	Agarose gel separates DNA fragments by size and charge for analysis.
62	A	Transformation introduces recombinant DNA into host bacteria.
63	A	PCR amplifies small DNA fragments for diagnostics.
64	A	Restriction enzymes cut DNA at palindromic sequences to create recombinant molecules.
65	A	Reverse transcriptase synthesizes cDNA from RNA for cloning.
66	A	Bioreactors allow large-scale production of enzymes, vaccines, or insulin.
67	A	Bt cotton expresses Cry protein from Bacillus thuringiensis for pest resistance.
68	A	Southern blot detects presence of specific DNA fragments in recombinant experiments.
69	A	Golden rice produces beta-carotene via inserted transgenes.
70	A	Gene therapy corrects defective genes by inserting functional copies.
71	A	Taq polymerase is thermostable, essential for PCR heat cycles.
72	A	cDNA is intron-free, allowing expression in bacterial hosts.
73	A	Biosafety labs prevent accidental release of recombinant microbes.
74	A	Antibiotic resistance markers allow identification of transformed cells.
75	A	Ethical review ensures responsible and safe use of biotechnology.

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Disclaimer:
All MCQs and answers are for educational purposes only. They are based on NCERT and NEET syllabus and do not represent official NEET questions.

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