Top 50+ Biotechnology Principles and Processes - Biology Questions and Answers For NEET 2024 Exam Preparation

Q1. A bacterial cell was transformed with a recombinant DNA that was generated using a human gene. However, the transformed cells did not produce the desired protein. Reasons could be

1. Amino acid codons for humans and bacteria are different.
2. Human gene may have intron which bacteria cannot process.
3. Human protein is formed but degraded by bacteria.
4. All the above

Answer: (b)

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Q2. Which of the following is not a component of downstream processing?

1. Preservation
2. Purification
3. Expression
4. Separation

Answer: (c)

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Q3. Assertion: Alien DNA if linked to plasmid it can be cloned.

Reason: Plasmid contains ORI.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (b)

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Q4. An enzyme catalysing the removal of nucleotides from the ends of DNA is

1. exonuclease
2. endonuclease
3. DNA ligase
4. Hind II

Answer: (a)

Restriction enzymes belong to a class of enzymes called nucleases, which are of two types

1. Exonucleases remove nucleotides from the ends of the DNA.
2. Endonucleases cuts at specific position within the DNA.

DNA ligase is a sealing enzymes which is also called as genetic gums, which is responsible for joining of two individual fragments of DNA, whereas Hind II is first discovered restriction endonuclease enzyme.

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Q5. The extraction of DNA from a gel piece is known as

1. Elution
2. Spooling
3. AGE
4. Annealing

Answer: (a)

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Q6. The linking of antibiotic resistance gene with the plasmid vector became possible with

1. DNA polymerase
2. endonucleases
3. DNA ligase
4. exonucleases

Answer: (c)

The linking of antibiotic resistance gene with the plasmid vector became possible with DNA ligase. DNA ligase is an enzyme that is able to join together two cut portions of DNA and therefore plays an important role in DNA repair. DNA ligase is also used in recombinant DNA technology as it ensures that the foreign DNA is bound to the plasmid into which it is incorporated.

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Q7. In continuous culture system,

1. biomass produced is high
2. used medium is drained out
3. no new medium is added
4. Both (a) and (b)

Answer: (d)

In continuous culture system, the used medium is continuously drained out from one side, while simultaneously fresh medium is added from the other to maintain the cells in their physiologically most active log phase. This type of method produces a larger biomass leading to higher yield of desired products.

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Q8. The cutting of DNA at specific locations became possible with the discovery of

1. restriction enzymes
2. ligases
3. selectable markers
4. probes.

Answer: (a)

Restriction enzymes recognise specific base sequences in a DNA molecule and cut its strands, e.g., EcoRI cuts DNA strands in the base sequence GAATTC.

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Q9. What type of enzyme is used in recombinant DNA technology to split a specific sugar phosphate bond in each strand of a DNA double helix ?

1. Lipase
2. Restriction enzyme
3. Esterase
4. Ligase

Answer: (b)

An esterase enzyme cleaves ester bonds. The restriction enzyme cleaves sugar phosphate bonds in DNA. The lipase enzyme breaks down fats. The ligase enzyme reforms sugar phosphate bonds after annealing.

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Q10. The host cultured in a continuous culture system where inside the used medium is drained out from one side while fresh medium is added from the other to maintain cells in their physiologically _________ phase.

1. Log
2. Lag
3. Stationary
4. Declining

Answer: (a)

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Q11. E' is

1. $tet^R$ gene
2. $Amp^R$ gene
3. $Chlor^R$ gene
4. $Eco^R$ gene

Answer: (a)

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Q12. Which of the following is not necessary to execute a polymerase chain reaction successfully?

1. Short DNA base primers
2. All four DNA bases
3. DNA polymerase
4. DNA library

Answer: (d)

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Q13. For selectable marker.

1. It helps to select the host cells which contain the vector and eliminate the non-transformants.
2. Genes encoding resistance to antibiotics like ampicillin, chloramphenicol, tetracycline or kanamycin, are useful selectable markers for E.coli.

Which of the statements given above are correct?

1. Only II
2. Only I
3. I and II
4. None of these

Answer: (c)

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Q14. Statement 1: In recombinant DNA technology, human genes are often transferred into bacteria (prokaryotes) or yeast (eukaryote).
Statement 2: Both bacteria and yeast multiply very fast to form huge population which express the desired gene.

1. Statement -1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement – 1
2. Statement- 1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
3. Statement - 1 is True, Statement- 2 is False
4. Both the Statements are False.

Answer: (b)

Bacteria and yeast are easily grow in culture medium and multiply very fast so it is best for making the many copies of recombinant DNA, and express character of desired gene.

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Q15. Which match is correct for the enzyme which is used to extract DNA in following organism?

1. Fungus–Chitinase
2. Plant cell–Cellulose
3. Bacteria–Lysozyme
4. All are correct

Answer: (d)

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Q16. Which of the following is not required in the preparation of a recombinant DNA molecule?

1. DNA ligase
2. Restriction endonuclease
3. DNA fragments
4. E. coli

Answer: (d)

E. coli is not required in the preparation of recombinant DNA molecules.

On the other hand, restriction endonuclease and DNA ligase can be used to make a stable recombinant DNA molecule with DNA fragments that have been obtained from different organisms.

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Q17. The linking of antibiotic resistance gene with the plasmid vector became possible with

1. DNA ligase
2. exonucleases
3. DNA polymerase
4. endonucleases.

Answer: (a)

The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid. The cutting of DNA at specific locations became possible with the discovery of the so-called 'molecular scissors' – restriction enzymes. The cut piece of DNA was then linked with the plasmid DNA.

This plasmid DNA acts as vector to transfer the piece of DNA attached to it. The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends.

This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.

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Q18. A single strand of nucleic acid tagged with a radioactive molecule is called

1. plasmid
2. selectable marker
3. vector
4. probe.

Answer: (d)

Probes are single stranded, radiolabelled molecules of nucleic acids with known sequence. The probes having sequence complementary to the gene to be identified are supplied. They bind with the particular gene segment. Radiation imaging identifies the location of that particular segment which bind with probe. Probes are used as identification tool.

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Q19. During heat shock to the bacterium, the temperature used for giving thermal shock is

1. liquid nitrogen
2. 100°C
3. 52°C
4. 42°C

Answer: (d)

During heat shock to the bacterium, the temperature used for giving thermal shock is 42º C. This enables the bacteria to take up the recombinant DNA.

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Q20. Restriction' in restriction enzyme refers to

1. cutting of DNA at specific position only
2. cleaving of phosphodiester bond in DNA by the enzyme
3. prevention of the multiplication of bacteriophage in bacteria
4. All of the above

Answer: (a)

The restriction enzymes are known as 'molecular scissors and are responsible for cutting DNA. These enzymes belong to a class of enzymes called nucleases. They are of two types:

1. Exonucleases : Cut DNA at the ends
2. Endonucleases : Make cuts at specific positions within the DNA.

These enzymes are present in bacteria to provide a type of defense mechanism called the 'restriction-modification system'.

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Q21. Assertion: Insertion of recombinant DNA within the coding sequence of b-galactosidase results in colourless colonies.

Reason: Presence of insert results in inactivation of enzyme b-galactosidase known as insertional inactivation.

1. If Assertion is true but Reason is false.
2. If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
3. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
4. If both Assertion and Reason are false.

Answer: (c)

Alternative markers have been developed that can differentiate recombinants from non-recombinants based upon their ability to produce colour in presence of a chromogenic substrate. The plasmid in the bacteria, lacking an insert produces blue coloured colonies, while those plasmids with an insert do not produce any colour due to insertional inactivation of enzyme, β-galactosidase.

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Q22. Restriction enzyme belongs to which class of enzymes?

1. Exonucleases
2. Ligases
3. Nucleases
4. Proteases

Answer: (c)

Restriction enzymes belong to a larger class of enzymes called nucleases, which are of two kinds, i.e. exonucleases and endonucleases.

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Q23. The first restriction enzyme was isolated from

1. Haemophilus influenzae
2. E. coli
3. Pseudomonas
4. Xanthomonas

Answer: (a)

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Q24. Which one of the following palindromic base sequences in DNA can be easily cut at about the middle by some particular restriction enzyme?

1. 5'.............GATATG.............3'3'.............CTACTA.............5'
2. 5'.............CGTTCG.............3'3'.............ATGGTA.............5'
3. 5'.............GAATTC.............3'3'.............CTTAAG.............5'
4. 5'.............CACGTA.............3'3'.............CTCAGT.............5'

Answer: (c)

Palindromic sequences in DNA molecule are group of bases that forms the same sequence when read in both forward and backward direction. In the given question, only option (c) represent a palindromic sequence.

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Q25. Transgenic plants are produced by inserting desired genes in

1. $T_i$ plasmids
2. pBR322
3. Lambda phage
4. None of these

Answer: (a)

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Q26. The correct order of steps in Polymerase Chain Reaction (PCR) is

1. Annealing, Extension, Denaturation
2. Denaturation, Extension, Annealing
3. Extension, Denaturation, Annealing
4. Denaturation, Annealing, Extension

Answer: (d)

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Q27. In bacterial cells, the membrane is digested with the help of enzyme

1. lysozyme
2. cellulase
3. chitinase
4. lipase

Answer: (a)

In bacterial cells, the cell wall (membrane) is digested with the help of the enzyme lysozyme. On the other hand,

• Cellulase and chitinase enzymes are used for the digestion of plant and fungal cell walls, respectively.
• Lipids can be removed with the treatment of the enzyme lipase.

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Q28. Polyethylene glycol method is used for

1. energy production from sewage
2. seedless fruit production
3. biodiesel production
4. gene transfer without a vector

Answer: (d)

Direct gene transfer is the transfer of naked DNA into plant cells, but the presence of rigid plant cell wall acts as a barrier to uptake. Therefore, protoplasts are the favoured target for direct gene transfer.

Polyethylene glycol mediated DNA uptake is a direct gene transfer method that utilizes the interaction between PEG, naked DNA, salts and the protoplast membrane to effect transport of the DNA into the cytoplasm.

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Q29. DNA finger-printing refers to

1. techniques used for molecular analysis of different specimens of DNA
2. analysis of DNA samples using imprinting device
3. molecular analysis or profiles of DNA samples
4. techniques used for identification of fingerprints of individuals

Answer: (c)

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Q30. There is a restriction endonuclease called EcoRI. What does .co part in it stand for ?

1. Coelom
2. Colon
3. Coenzyme
4. coli

Answer: (d)

EcoRI is an endonuclease enzyme isolated from strains of E.coli and a part of restriction modified system. So, .co part stands for coli.

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Q31. Biotechnology deals with techniques of using which of the following to produce product and processes useful to humans?

1. Live organism
2. Enzyme from organism
3. Vitamins
4. Both (a) and (b)

Answer: (d)

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Q32. Significance of heat shock method in bacterial transformation is to facilitate.

1. Uptake of DNA through membrane transport proteins
2. Binding of DNA to the cell wall
3. Uptake of DNA through transient pores in the bacterial cell wall
4. Expression of antibiotic resistance gene

Answer: (c)

In the process of chemical method, the cell is treated with specific concentration of a divalent cation such as calcium to increase pore size in cell wall. Later the cells are incubated with recombinant DNA on ice, which is followed by placing them briefly at 42°C and then putting it again on ice. this process is called heat shock method. The bacteria now takes up the recombinant DNA.

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Q33. Find out the pairs, which are correctly matched.

1. A-(2); B-(1); C-(4); D-(3)
2. A-(4); B-(1); C-(2); D-(3)
3. A-(4); B-(1); C-(3); D-(2)
4. A-(1); B-(4); C-(2); D-(3)

Answer: (b)

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Q34. Which one of the following techniques made it possible to genetically engineer living organisms?

1. X-ray diffraction
2. Recombinant DNA techniques
3. Heavier isotope labelling
4. Hybridization

Answer: (b)

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Q35. Two microbes found to be very useful in genetic engineering are

1. Vibrio cholerae and a tailed bacteriophage
2. Escherichia coli and Agrobacterium tumefaciens
3. crown gall bacterium and Caenorhabditis elegans
4. Diplococcus sp. and Pseudomonas sp.

Answer: (b)

E.coli contains many important standard cloning vectors widely used in gene cloning experiments like pBR322 contains origin of replication (ori). Other cloning vectors like PACYC177, pBR324, PRK 64.6 contain ampicillin resistance gene they are also found in E.coli. Among higher plants, Ti plasmid of Agrobacterium tumefaciens and Ri plasmid of A. rhizogenes is the best known vector.

T-DNA from Ti or Ri plasmid of Agrobacterium is considered to be a very potential vector for cloning experiments with higher plants.

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Q36. Which one is a true statement regarding DNA polymerase used in PCR?

1. It is isolated from a virus.
2. It serves as a selectable marker.
3. It is used to ligate introduced DNA in recipient cells.
4. It remains active at high temperature.

Answer: (d)

In PCR, Taq polymerase is used which is obtained from Thermus aquaticus bacteria. It is a relatively thermostable enzyme thus used in PCR as during the process the step involving denaturation of DNA strands requires high temperature.

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Q37. Find the true statement.

1. Some bacterial cell may have copy number of plasmid that varies from 15–100.
2. Ori means origin of transcription.
3. Vector should have many recognition sites for commonly used restriction enzymes so that alien DNA can attach to any one of the sites easily.
4. $tet^R$ gene in pBR322 can be cleaved by PvuI and PstI.

Answer: (a)

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Q38. A kind of biotechnology involving manipulation of DNA is called

1. denaturation
2. genetic engineering
3. DNA replication
4. renaturation

Answer: (b)

Genetic engineering is the manipulation of genes by man in vitro. Genetic engineering refers to artificial synthesis, isolation, modification, combination, addition and repair of the genetic material (DNA) to alter the phenotype of the host organism to suit human needs. Three techniques of genetic engineering are:

1. rDNA (recombinant DNA technology)
2. gene cloning/gene amplification
3. gene therapy

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Q39. Transgenic plants are the ones

1. Produced by a somatic embryo in artificial medium.
2. Grown in artificial medium after hybridization in the field.
3. Generated by introducing foreign DNA into a cell and regenerating a plant from the cell.
4. Produced after protoplast fusion in an artificial medium.

Answer: (c)

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Q40. Stirred-tank bioreactors have been designed for the

1. addition of preservatives to the product
2. purification of the product
3. availability of oxygen throughout the bioreactor
4. ensuring anaerobic conditions in the culture vessel

Answer: (c)

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Q41. When scientists make an animal superior by view of genotype, introducing some foreign genes in it, is called

1. tissue culture
2. genetic engineering
3. immunization
4. biotechnology

Answer: (b)

Genetic engineering is an experimental manipulation of genetic material, especially for industrial or medical uses. It encompasses the techniques of gene cloning, the DNA modification by changes in sequence arrangement or deletion, and the introduction of novel genes into cells and organisms.

It may prove possible to advantageously modify the genes of farmed animals, to correct genetic deficiencies of the human by inserting novel genes. This can be done by breakage of a DNA molecule at two desired places into another DNA molecule of the desired animal.

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Q42. Which of the following is not a feature of the plasmids?

1. Independent replication
2. Single-stranded
3. Transferable
4. Circular structure

Answer: (b)

Plasmids are extra-chromosomal, selfreplicating, usually circular, double-stranded DNA molecules that serve as vectors which carry foreign DNA segment and replicate inside host cell.

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Q43. Which one is a true statement regarding DNA polymerase used in PCR?

1. It is isolated from a virus.
2. It serves as a selectable marker.
3. It is used to ligate introduced DNA in recipient cells.
4. It remains active at high temperature

Answer: (d)

In PCR, Taq polymerase is used which is obtained from Thermus aquaticus bacteria. It is a relatively thermostable enzyme thus used in PCR as during the process the step involving denaturation of DNA strands requires high temperature.

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Q44. The best cloning organism for genetic engineering and biotechnology is

1. Pseudomonas
2. Agrobacterium
3. E. coli
4. Lambda phage

Answer: (c)

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Q45. Genetic engineering is possible, because

1. the phenomenon of transduction in bacteria is well underwood
2. restriction endonucleases purified from bacteria can be used in vitro
3. we can cut DNA at specific sites by endonucleases like DNase I
4. we can see DNA by electron microscope.

Answer: (b)

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Q46. Silencing of mRNA has been used in producing transgenic plants resistant to

1. Nematodes
2. Bollworms
3. Bacterial blights
4. White rusts

Answer: (a)

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Q47. Rising of dough is due to

1. Production of $CO_2$
2. Multiplication of yeast
3. Emulsification
4. Hydrolysis of wheat flour starch into sugars

Answer: (a)

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Q48. Statement 1: Interferons are effective against viruses.

Statement 2: Proteins which can be synthesized only by genetic engineering are effective against viruses.

1. Statement -1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement – 1
2. Statement- 1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
3. Statement - 1 is True, Statement- 2 is False
4. Both the Statements are False.

Answer: (c)

Interferons are proteins that are effective against most viruses. They are naturally produced by virus infected cells. The proteins interact with adjacent cells and make them resistant to virus attack. Now interferons are also being manufactured through genetic engineering. Interferons control the multiplication of virus particles by inhibiting their protein synthesis.

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Q49. In vitro clonal propagation in plants is characterized by

1. electrophoresis and HPLC
2. Northern blotting
3. PCR and RAPD
4. microscopy

Answer: (c)

Clonal propagation can be characterized by PCR and RAPD. The polymerase chain reaction (PCR) technique, generates microgram (µg) quantities of DNA copies (upto billion copies) of the desired DNA (or RNA) segment, present even as a single copy in the initial preparation, in a matter of few hours. RAPD stands for Random Amplification of Polymorphic DNA.

It is a type of PCR, but the segments of DNA that are amplified are random. No knowledge of the DNA sequence for the targeted gene is required, as the primers will bind somewhere in the sequence, but it is not certain exactly where. Its resolving power is much lower than targeted, species specific DNA comparison methods, such as short tandem repeats.

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Q50. Biolistics (gene-gun) is suitable for

1. Transformation of plant cells.
2. Disarming pathogen vectors.
3. DNA finger printing.
4. Constructing recombinant DNA molecules.

Answer: (d)

Biolistic (gene gun) is direct gene transferred method for constructing recombinant DNA. The gene gun was invented by John C. Sanford with Edward Wolf. A gene gun can be used to genetically infect cells or whole organisms with foreign DNA by aiming the barrel of the gun and firing.

The micro shot projectiles in the biolistic gene gun are made of microscopic (or nano) sized gold or platinum powders. These expensive powders are soaked in DNA or RNA (in raw or plasmid form) that are engineered for insertion into the genome of the cells or organisms under the gun.

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