Biotechnology: Principles and Processes NEET PYQReal NEET & AIPMT 2005–2021 questions, year-tagged, with solutions
By the RankUp team, founded by Dr. Deepak Sahu (MBBS Gold Medalist, NEET PG AIR 1731) · Updated
Every Biotechnology: Principles and Processes question from the NEET & AIPMT papers on this site (2005–2021), newest first. Each is tagged with its paper. Tap an option to check your answer and read the explanation.
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Biotechnology: Principles and Processes previous year questions
55 questions. Tap an option to check your answer.
Q1NEET 2021
DNA strands on a gel stained with ethidium bromide when viewed under UV radiation, appear as :
Not quite — the answer is B.
Ethidium bromide intercalates into DNA and fluoresces under UV light, so the separated DNA fragments are seen as bright orange bands. They are not visible as bands without the stain and UV exposure.
Q2NEET 2021
During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out :
Not quite — the answer is B.
After the cell is lysed and RNA, proteins and other molecules are removed with enzymes, adding chilled ethanol makes the purified DNA come out of solution as fine threads. RNA is removed earlier by ribonuclease, not precipitated at this step.
Q3NEET 2021
Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction) ?
Not quite — the answer is A.
Each PCR cycle first denatures the double-stranded DNA by heat, then lets the primers anneal to the single strands, and finally extends the primers using a thermostable DNA polymerase. Extension cannot come before annealing because the polymerase needs a primer to start.
Q4NEET 2021
Plasmid pBR322 has PstI restriction enzyme site within gene ampᴿ that confers ampicillin resistance. If this enzyme is used for inserting a gene for β-galactoside production and the recombinant plasmid is inserted in an E.coli strain
Not quite — the answer is A.
PstI cuts inside the ampicillin resistance gene, so inserting a foreign gene there disrupts it by insertional inactivation and the recombinant plasmid can no longer make the host resistant to ampicillin. The transformed cells therefore cannot both resist ampicillin and express the new gene.
Q5NEET 2021
A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is :
Not quite — the answer is C.
Restriction endonucleases recognise palindromic nucleotide sequences, which read the same on both strands in the 5′→3′ direction, and cut at specific positions within them. Okazaki fragments and poly-A tails are unrelated to restriction sites.
Q6NEET 2021
During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first ?
Not quite — the answer is C.
The first step of PCR, denaturation, needs a very high temperature (about 94 °C) to separate the two DNA strands, so it is affected first if that temperature is not reached. Ligation is not a PCR step at all.
Q7NEET 2020 · Q7
Choose the correct pair from the following:
Not quite — the answer is A.
DNA ligase joins DNA fragments, for example sealing a gene into a vector. Polymerases synthesise DNA rather than break it, nucleases break phosphodiester bonds rather than separate strands, and it is endonucleases, not exonucleases, that cut at specific positions within the DNA.
Q8NEET 2020 · Q18
In gel electrophoresis, separated DNA fragments can be visualized with the help of:
Not quite — the answer is B.
After gel electrophoresis the DNA is stained with ethidium bromide and seen as bright orange bands under UV light. Acetocarmine is a chromosome stain used in light microscopy, and ethidium bromide does not fluoresce usefully under infrared.
Q9NEET 2020 · Q21
The specific palindromic sequence which is recognized by EcoRI is:
Not quite — the answer is A.
EcoRI recognises the palindrome 5'-GAATTC-3' paired with 3'-CTTAAG-5', which reads the same on both strands in the 5'→3' direction. GGATCC is the BamHI site, and writing CTTAAG as the top 5'→3' strand is not the EcoRI site.
Q10NEET 2020 · Q27
Match the organism with its use in biotechnology. (a) Bacillus thuringiensis | (i) Cloning vector (b) Thermus aquaticus | (ii) Construction of first rDNA molecule (c) Agrobacterium tumefaciens | (iii) DNA polymerase (d) Salmonella typhimurium | (iv) Cry proteins Select the correct option from the following:
Not quite — the answer is B.
Bacillus thuringiensis gives cry proteins, Thermus aquaticus gives the thermostable Taq DNA polymerase, Agrobacterium tumefaciens (Ti plasmid) is used as a cloning vector, and a plasmid of Salmonella typhimurium was used to make the first rDNA molecule. Hence cry proteins, DNA polymerase, cloning vector, first rDNA is the correct order.
Q11NEET 2020 · Q78
The sequence that controls the copy number of the linked DNA in the vector, is termed:
Not quite — the answer is B.
The origin of replication (ori) is where replication starts, and it also controls the copy number of the linked DNA in the vector. Selectable markers help pick transformants, and palindromic and recognition sequences are restriction enzyme sites.
Q12NEET 2019 · Q113
Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes ?
Not quite — the answer is D.
Large volumes (100–1000 litres) of culture are grown in bioreactors, which provide optimal temperature, pH, aeration and mixing. A sludge digester is used in sewage treatment, not enzyme production.
Q13NEET 2019 · Q122
DNA precipitation out of a mixture of biomolecules can be achieved by treatment with :
Not quite — the answer is B.
In the NCERT protocol, purified DNA is precipitated by adding chilled ethanol and appears as fine threads. Chloroform is used to remove proteins, not to precipitate DNA.
Q14NEET 2019 · Q145
Following statements describe the characteristics of the enzyme Restriction Endonuclease. Identify the incorrect statement.
Not quite — the answer is B.
A restriction endonuclease recognises a specific palindromic sequence and cuts the sugar-phosphate backbone of both strands at specific positions, so the claim that it cuts only one of the two strands is the incorrect statement. Cutting at an identified position within the DNA is exactly what an endonuclease does, so that statement is correct.
Q15NEET 2018 · Q101
The correct order of steps in Polymerase Chain Reaction (PCR) is
Not quite — the answer is D.
Each PCR cycle first denatures double-stranded DNA by heat, then lets the primers anneal to the single strands at a lower temperature, and finally Taq polymerase extends the primers. Extension cannot happen before annealing because the polymerase needs a primer to start from.
Q16NEET 2017 · Q56
A gene whose expression helps to identify transformed cell is known as:
Not quite — the answer is A.
A selectable marker, such as a gene for ampicillin or tetracycline resistance, lets transformants be picked out because only they survive on the selective medium. A vector or plasmid is the carrier of the DNA, not the identifying gene.
Q17NEET 2017 · Q80
DNA fragments are:
Not quite — the answer is B.
The phosphate groups of the sugar–phosphate backbone carry negative charges, so all DNA fragments are negatively charged and move towards the anode in electrophoresis. Size changes how fast they move, not the sign of their charge.
Q18NEET 2017 · Q84
The process of separation and purification of expressed protein before marketing is called:
Not quite — the answer is B.
After biosynthesis in the bioreactor, the product is separated, purified, formulated with preservatives and put through quality control; these steps together are downstream processing. Upstream processing is the earlier stage of preparing the organism and growing it.
Q19NEET 2017 · Q105
The DNA fragments separated on an agarose gel can be visualised after staining with:
Not quite — the answer is D.
DNA in the gel is stained with ethidium bromide and seen as bright orange bands under UV light. Bromophenol blue is only a tracking dye that shows how far the run has gone, and does not stain DNA bands.
Q20NEET 2017 (Gujarati paper) · Q123
Restriction endonucleases are:
Not quite — the answer is B.
Restriction endonucleases are made by bacteria to cut the DNA of invading bacteriophages, restricting their growth, which is a defence mechanism. Joining DNA molecules is done by DNA ligase, and DNA synthesis in vitro needs DNA polymerase.
Q21NEET 2016 Phase 2 · Q125
Stirred-tank bioreactors have been designed for
Not quite — the answer is C.
The stirrer in a stirred-tank bioreactor mixes the contents and spreads sterile air bubbles evenly, so oxygen is available throughout the culture. Purification and preservation belong to downstream processing, and the design supplies air rather than keeping conditions anaerobic.
Q22NEET 2016 Phase 2 · Q126
A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using
Not quite — the answer is D.
DNA ligase seals the sugar-phosphate backbone between the matching sticky ends of the vector and insert, forming the recombinant plasmid. EcoRI only cuts DNA, and Taq polymerase and polymerase III synthesise new strands rather than join fragments.
Q23NEET 2016 Phase 2 · Q127
Which of the following is not a component of downstream processing?
Not quite — the answer is D.
Downstream processing starts after the product is made and includes separation, purification and formulation with preservatives. Expression of the gene in the host happens earlier, during the bioreactor stage, so it is not part of downstream processing.
Q24NEET 2016 Phase 2 · Q128
Which of the following restriction enzymes produces blunt ends?
Not quite — the answer is B.
EcoRV cuts both strands at the same point in the middle of its recognition site GATATC, giving blunt ends. SalI, XhoI and HindIII make staggered cuts and leave sticky single-stranded overhangs.
Q25NEET 2016 Phase 1 · Q123
Which of the following is not a feature of the plasmids?
Not quite — the answer is D.
Plasmids are extrachromosomal, circular, double-stranded DNA molecules that replicate independently of the chromosome and can be transferred between cells. They are not single-stranded.
Q26NEET 2016 Phase 1 · Q132
The taq polymerase enzyme is obtained from:
Not quite — the answer is A.
Taq polymerase is a heat-stable DNA polymerase isolated from the thermophilic bacterium Thermus aquaticus, which lets it survive the high denaturation temperature in PCR. The other bacteria are not its source.
Q27NEET 2016 Phase 1 · Q151
Which of the following is a restriction endonuclease?
Not quite — the answer is A.
Hind II, from Haemophilus influenzae, was the first restriction endonuclease isolated and cuts DNA at a specific recognition sequence. DNase I cuts DNA non-specifically, while proteases and RNases do not act on DNA.
Q28AIPMT 2014
Which vector can clone only a small fragment of DNA?
Not quite — the answer is B.
Plasmids can accept only small inserts (roughly up to 10 kb). Cosmids carry about 40–45 kb, BACs about 100–300 kb and YACs even larger fragments, which is why they are used for big genomic DNA pieces.
Q29NEET 2013
DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by
Not quite — the answer is C.
DNA fragments, being negatively charged, move towards the anode through an agarose gel and are separated by size in gel electrophoresis. PCR amplifies DNA and does not separate fragments.
Q30NEET 2013
Which of the following is not correctly matched for the organism and its cell wall degrading enzyme?
Not quite — the answer is C.
Methylase adds methyl groups to DNA and does not break down cell walls, so pairing it with algae is the wrong match. Lysozyme breaks bacterial walls, cellulase plant walls and chitinase fungal walls.
Q31AIPMT 2012 Mains
Biolistics (gene-gun) is suitable for
Not quite — the answer is B.
In biolistics, gold or tungsten microparticles coated with DNA are shot into cells, a method suited to transforming plant cells. Disarming pathogens and joining DNA to vectors are done with enzymes, not a gene gun.
Q32AIPMT 2012 Mains
In genetic engineering, the antibiotics are used
Not quite — the answer is A.
Antibiotic-resistance genes on a vector act as selectable markers: only transformed cells survive on medium containing the antibiotic. The replication start site is the ori, not an antibiotic sequence.
Q33AIPMT 2012 Mains
Which one of the following represents a palindromic sequence in DNA ?
Not quite — the answer is A.
5′–GAATTC–3′ reads the same 5′→3′ on both strands (the EcoRI site), which makes it a palindrome. In the other options the second strand does not read the same as the first in the 5′→3′ direction.
Q34AIPMT 2012 Prelims
Which one of the following is a case of wrong matching ?
Not quite — the answer is C.
A vector DNA (such as a plasmid) carries the foreign gene into the host cell and lets it replicate; it is not a site of tRNA synthesis. Callus, somatic hybridisation and micropropagation are all correctly described.
Q35AIPMT 2012 Prelims
A single strand of nucleic acid tagged with a radioactive molecule is called
Not quite — the answer is A.
A probe is a single-stranded DNA or RNA tagged with a radioactive (or fluorescent) molecule that hybridises with its complementary sequence and is detected by autoradiography. Vectors and plasmids carry genes into hosts, and selectable markers identify transformants.
Q36AIPMT 2012 Prelims
For transformation, micro-particles coated with DNA to be bombarded with gene gun are made up of
Not quite — the answer is A.
In biolistics (gene gun), DNA is coated onto high-velocity microparticles of gold or tungsten and fired into plant cells. Silver, platinum, zinc and silicon are not used.
Q37AIPMT 2012 Prelims
Which one is a true statement regarding DNA polymerase used in PCR ?
Not quite — the answer is A.
The DNA polymerase used in PCR is Taq polymerase from the bacterium Thermus aquaticus, which stays active at the high temperatures used to denature DNA. It is isolated from a bacterium, not a virus, and it does not ligate DNA or act as a selectable marker.
Q38AIPMT 2011 Mains
Which one of the following techniques made it possible to genetically engineer living organisms?
Not quite — the answer is C.
Recombinant DNA technology, cutting and joining DNA with restriction enzymes and ligase and inserting it into a host, made it possible to genetically engineer organisms. Isotope labelling and X-ray diffraction were tools for studying DNA, and hybridization is conventional breeding.
Q39AIPMT 2011 Prelims
Agarose extracted from sea weeds finds use in
Not quite — the answer is A.
Agarose, a polysaccharide extracted from seaweeds, forms the gel matrix used in gel electrophoresis to separate DNA fragments by size. It plays no matrix role in spectrophotometry or PCR.
Q40AIPMT 2011 Prelims
Given below is a sample of a portion of DNA strand giving the base sequence on the opposite strands. What is so special shown in it? 5′ ____ GAATTC ____ 3′ 3′ ____ CTTAAG ____ 5′
Not quite — the answer is A.
The sequence 5′-GAATTC-3′ reads the same on the opposite strand when both are read 5′→3′, so it is a palindromic sequence. This is the recognition site of EcoRI. Nothing in it indicates deletion or a start codon (AUG/ATG).
Q41AIPMT 2011 Prelims
There is a restriction endonuclease called EcoRI. What does "co" part in it stand for?
Not quite — the answer is A.
Restriction enzymes are named after their source: in EcoRI, 'E' is the genus Escherichia, 'co' is the species coli, 'R' is the strain RY13 and 'I' the order of isolation.
Q42AIPMT 2010 Mains · Q9
Which of the following are used in gene cloning?
Not quite — the answer is D.
Plasmids are small, autonomously replicating, extrachromosomal circular DNA molecules of bacteria and are the commonest cloning vectors (e.g. pBR322). Mesosomes and nucleoids are bacterial cell structures and lomasomes are fungal membrane bodies; none of them carry foreign DNA.
Q43AIPMT 2010 Mains · Q49
In genetic engineering, a DNA segment (gene) of interest, is transferred to the host cell through a vector. Consider the following four agents (A-D) in this regard and select the correct option about which one or more of these can be used as a vector/vectors Statements (A) A bacterium (B) Plasmid (C) Plasmodium (D) Bacteriophage
Not quite — the answer is D.
The standard cloning vectors are plasmids and bacteriophages, because both replicate inside bacteria and can carry inserted DNA. Plasmodium is a protozoan parasite and is never used as a vector.
Q44AIPMT 2010 Prelims · Q191
Stirred-tank bioreactors have been designed for
Not quite — the answer is A.
A stirred-tank bioreactor uses a stirrer and a sparging system to mix the contents evenly and keep oxygen available throughout the culture. Purification and adding preservatives belong to downstream processing, not to the bioreactor.
Q45AIPMT 2010 Prelims · Q194
Which one of the following is used as vector for cloning genes into higher organisms?
Not quite — the answer is A.
Retroviruses can turn normal animal cells cancerous, but when disarmed they are used as vectors to deliver genes into animal cells. Baculoviruses are used as biocontrol agents against insects, and Salmonella and Rhizopus are not cloning vectors.
Q46AIPMT 2010 Prelims · Q197
Restriction endonucleases are enzymes which
Not quite — the answer is B.
Restriction endonucleases recognise a specific palindromic sequence and cut the DNA at specific positions within the molecule. Removing nucleotides from the ends is what exonucleases do.
Q47AIPMT 2010 Prelims · Q200
Which one of the following palindromic base sequences in DNA can be easily cut at about the middle by some particular restriction enzyme?
Not quite — the answer is D.
5′-GAATTC-3′ / 3′-CTTAAG-5′ reads the same 5′→3′ on both strands, which makes it a true palindrome. It is the EcoRI recognition site, which is cut between G and A. The other pairs are not even complementary strands, let alone palindromes.
Q48AIPMT 2009 Prelims · Q55
Polyethylene glycol method is used for:
Not quite — the answer is D.
Polyethylene glycol (PEG) makes plant protoplast membranes permeable or fuse, so naked DNA can be taken up directly; it is a vectorless (direct) gene transfer method. It has nothing to do with biodiesel or seedless fruits.
Q49AIPMT 2009 Prelims · Q58
Which one of the following is commonly used in transfer of foreign DNA into crop plants?
Not quite — the answer is B.
Agrobacterium tumefaciens naturally transfers a piece of its Ti plasmid (T-DNA) into dicot plant cells, and the disarmed Ti plasmid is used as a vector to deliver genes into crop plants. Meloidogyne incognita is a nematode pest and Trichoderma is a biocontrol fungus, not a vector.
Q50AIPMT 2008 Prelims · Q185
Gel electrophoresis is used for
Not quite — the answer is C.
In agarose gel electrophoresis negatively charged DNA fragments move toward the anode, and the gel's sieving effect separates them by size, smaller ones travelling farther. Cutting DNA is done by restriction enzymes and joining by ligase.
Q51AIPMT 2008 Prelims · Q193
The linking of antibiotic resistance gene with the plasmid vector became possible with
Not quite — the answer is B.
Cohen and Boyer joined the antibiotic resistance gene to the plasmid using DNA ligase, which seals the sugar-phosphate backbone between the cut ends. Restriction endonucleases only cut DNA; they do not join fragments.
Q52AIPMT 2006 Prelims · Q157
Microbes found to be very useful in genetic engineering are :
Not quite — the answer is A.
E. coli is the main host for cloning vectors, and Agrobacterium tumefaciens is used to transfer genes into plants through its Ti plasmid. Caenorhabditis elegans is a nematode, not a microbe.
Q53AIPMT 2006 Prelims · Q177
Restriction endonuclease :
Not quite — the answer is B.
A restriction endonuclease recognises a specific palindromic base sequence and cuts DNA at or near that site. It does not cut randomly or make DNA.
Q54AIPMT 2005 Prelims · Q122
Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain ?
Not quite — the answer is C.
Endonucleases cut phosphodiester bonds within a DNA or RNA chain; restriction enzymes are an example. Exonucleases remove nucleotides only from the ends. Lipases and proteases act on fats and proteins.
Q55AIPMT 2005 Prelims · Q131
Production of a human protein in bacteria by genetic engineering is possible because :
Not quite — the answer is D.
Because the genetic code is universal, bacterial ribosomes read a human gene's codons as the same amino acids and so make the human protein. Bacteria cannot splice introns (cDNA is used for that reason), and gene regulation differs between bacteria and humans.
How often Biotechnology: Principles and Processes came up
Questions from this chapter in each paper on this site.
- NEET 2021: 6
- NEET 2020: 5
- NEET 2019: 3
- NEET 2018: 1
- NEET 2017: 4
- NEET 2017 (Gujarati paper): 1
- NEET 2016 Phase 2: 4
- NEET 2016 Phase 1: 3
- AIPMT 2014: 1
- NEET 2013: 2
- AIPMT 2012 Mains: 3
- AIPMT 2012 Prelims: 4
- AIPMT 2011 Mains: 1
- AIPMT 2011 Prelims: 3
- AIPMT 2010 Mains: 2
- AIPMT 2010 Prelims: 4
- AIPMT 2009 Prelims: 2
- AIPMT 2008 Prelims: 2
- AIPMT 2006 Prelims: 2
- AIPMT 2005 Prelims: 2
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