25 questions in 25 minutes on the NTA computer-based test interface, all from Biotechnology: Principles and Processes. +4 / -1 marking, instant score, full solutions. Free, no login.
A chapter test is the fastest honest check on whether a chapter has actually landed. This one draws 25 questions from Biotechnology: Principles and Processes, of which 16 are real NEET previous-year questions and 0 sit at the harder end of the bank. Sit it in one 25-minute block, the way you would in the hall.
Revising first? Read the Biotechnology: Principles and Processes chapter notes, then come back and take this test to check it stuck.
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Duration: 180 minutes · 180 questions · 720 marks maximum
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NEET CBT mock test: common questions
How many questions are in this Biotechnology: Principles and Processes mock test?
25 questions in 25 minutes, marked +4 for a correct answer and -1 for a wrong one, exactly like the real paper. 16 of them are NEET previous-year questions.
Is this the same interface as the real NEET CBT?
Yes. On-screen countdown, colour-coded question palette, Save & Next, Clear Response and Mark for Review, then an instant score with full solutions.
Should I take this before or after revising Biotechnology: Principles and Processes?
Both, and that is the point. Take it cold to find out what you actually do not know, revise from the chapter notes, then retake it to confirm the gap closed.
All 25 questions with answers and solutions
The complete paper in text form, with the correct option and a worked explanation for every question. Sit the timed test above first: the score is only worth having if you earn it. Then open this to revise, or to re-read a question you got wrong without replaying the whole paper.
Show all 25 questions with answers and solutions
Zoology
- Q1DNA fragments generated by restriction endonucleases in a chemical reaction can be separated by:
- restriction mapping
- centrifugation
- electrophoresis
- polymerase chain reaction
Answer: (C) electrophoresis
DNA fragments produced by restriction digestion are separated by gel electrophoresis according to size. PCR amplifies DNA (it does not separate fragments), and restriction mapping is an analysis method, not a separation technique.
- Q2PCR and restriction fragment length polymorphism (RFLP) are the methods used for:
- genetic transformation
- study of enzymes
- DNA sequencing
- genetic fingerprinting
Answer: (D) genetic fingerprinting
PCR and RFLP are techniques used in genetic (DNA) fingerprinting, useful for identifying individuals from biological samples and in parentage disputes. They are not, by themselves, methods of genetic transformation or DNA sequencing.
- Q3In the name EcoRI, the letter ‘R’ stands for:
- The genus Escherichia
- The species coli
- The strain (RY13)
- The order of isolation
Answer: (C) The strain (RY13)
In EcoRI: E = genus Escherichia, co = species coli, R = strain RY13, and I (Roman numeral) = the first enzyme isolated from that strain.
- Q4In isolating DNA, purified DNA finally precipitates as fine threads when which chilled reagent is added?
- Liquid nitrogen
- Chilled water
- Concentrated HCl
- Chilled ethanol
Answer: (D) Chilled ethanol
After removing RNA (RNase) and proteins (protease), the purified DNA is precipitated by adding chilled ethanol, in which the DNA appears as a collection of fine, suspended threads (spooled out).
- Q5A bioreactor provides all the following optimal conditions for product formation EXCEPT:
- Optimum oxygen, substrate, salts and vitamins
- A constant ultraviolet irradiation to kill the culture
- Optimum temperature and pH
- Agitation for uniform mixing
Answer: (B) A constant ultraviolet irradiation to kill the culture
A bioreactor maintains optimum temperature, pH, substrate, vitamins, salts and oxygen, with agitation for mixing. Constant UV irradiation would kill the desired cells and is not a bioreactor function.
- Q6Which one of the following is used as a vector for cloning genes into higher organisms (animal cells)?
- Rhizopus nigricans
- Retrovirus
- Baculovirus
- Salmonella typhimurium
Answer: (B) Retrovirus
Retroviruses are RNA viruses that, having been disarmed, are used as vectors to deliver genes into animal (higher organism) cells. Salmonella and Rhizopus are not gene-cloning vectors for higher organisms in this context.
- Q7Manipulation of DNA in genetic engineering became possible due to the discovery of:
- restriction endonuclease
- DNA ligase
- primase
- transcriptase
Answer: (A) restriction endonuclease
The discovery of restriction endonucleases – enzymes that cut DNA at specific sequences – made precise manipulation of DNA possible, because digesting DNA with them generates a defined, isolatable set of fragments. Ligase joins (it follows cutting); transcriptase and primase are not the enabling discovery here.
- Q8The first restriction endonuclease discovered, which always cuts the DNA molecule at a particular point by recognising a specific sequence of six base pairs, is:
- Thermostable DNA polymerase
- EcoRI
- HindII
- Adenosine deaminase
Answer: (C) HindII
HindII (isolated by Smith, Wilcox and Kelly in 1968) was the first restriction endonuclease characterised; it cuts DNA at a fixed point within a specific recognition sequence of six base pairs. Adenosine deaminase and DNA polymerase are not restriction enzymes.
- Q9A specific recognition sequence that is identified by endonucleases to make cuts at specific positions within the DNA is the:
- poly(A) tail sequence
- palindromic nucleotide sequence
- Okazaki sequences
- degenerate primer sequence
Answer: (B) palindromic nucleotide sequence
Restriction endonucleases recognise palindromic nucleotide sequences (reading the same 5’→3′ on both strands) and cut DNA at specific positions within them. Okazaki fragments and poly(A) tails relate to replication and mRNA processing, not restriction sites; primers are for synthesis, not recognition.
- Q10The linking of an antibiotic-resistance gene with the plasmid vector became possible with:
- DNA polymerase
- DNA ligase
- exonucleases
- endonucleases
Answer: (B) DNA ligase
DNA ligase joins the cut ends of the antibiotic-resistance gene and the plasmid vector, making a new combination of autonomously replicating recombinant DNA. Endonucleases cut (not join), and polymerase/exonucleases do not seal fragments together.
- Q11A DNA sequence linked to an origin of replication, enabling it to replicate within a host, is called a:
- Codon
- Operon
- Cistron
- Replicon
Answer: (D) Replicon
A piece of DNA that can replicate because it carries an origin of replication (ori) is called a replicon. Operon is a regulatory gene cluster, codon is a triplet, and cistron is a gene coding for a polypeptide.
- Q12In the restriction endonuclease named EcoRI, what does the ‘co’ part stand for?
- coli
- Coenzyme
- Colon
- Coelom
Answer: (A) coli
In naming restriction enzymes the first letter is the genus and the next two letters the species. In EcoRI: E = Escherichia, co = coli (species), R = strain RY13, I = first enzyme isolated. So ‘co’ stands for the species coli.
- Q13During agarose gel electrophoresis of DNA, the fragments move toward the anode because DNA is negatively charged. Which fragments travel the farthest?
- The smallest fragments
- The largest fragments
- Only circular fragments
- All fragments move equally
Answer: (A) The smallest fragments
Smaller DNA fragments face less resistance in the agarose sieve and migrate farther from the well, while larger fragments move more slowly and remain nearer the well.
- Q14Stirred-tank bioreactors have been designed primarily for:
- availability of oxygen throughout the process
- addition of preservatives to the product
- purification of the product
- ensuring anaerobic conditions in the culture vessel
Answer: (A) availability of oxygen throughout the process
A stirred-tank bioreactor is usually cylindrical with a stirrer/agitator that ensures even mixing and uniform availability of oxygen throughout the vessel (aided by a sparger). Purification and preservative addition are downstream steps, and the cultures are aerobic, not anaerobic.
- Q15In gel electrophoresis, separated DNA fragments can be visualised with the help of:
- acetocarmine in UV radiation
- ethidium bromide in UV radiation
- acetocarmine in bright blue light
- ethidium bromide in infrared radiation
Answer: (B) ethidium bromide in UV radiation
Separated DNA fragments are stained with ethidium bromide and viewed under UV radiation, where the DNA-bound dye fluoresces as bright orange bands. Acetocarmine is a chromosome stain, and UV (not infrared) is the correct illumination.
- Q16Which of the following is the correct sequence of steps in a PCR (Polymerase Chain Reaction)?
- Extension, Denaturation, Annealing
- Denaturation, Annealing, Extension
- Annealing, Denaturation, Extension
- Denaturation, Extension, Annealing
Answer: (B) Denaturation, Annealing, Extension
In PCR, the template is first denatured at ~95°C (strands separate), then primers anneal at a lower temperature (~50°C), and finally Taq polymerase extends the primers. So the order is Denaturation → Annealing → Extension.
- Q17Which of the following is a restriction endonuclease?
- HindII
- RNase
- Protease
- DNase I
Answer: (A) HindII
HindII is a restriction endonuclease (the first one characterised). Protease degrades proteins, RNase degrades RNA, and DNase I is a non-specific nuclease – none of these recognise a specific palindromic site the way a restriction endonuclease does.
- Q18The DNA fragments separated on an agarose gel can be visualised after staining with:
- ethidium bromide
- acetocarmine
- aniline blue
- bromophenol blue
Answer: (A) ethidium bromide
DNA fragments are stained with ethidium bromide, an intercalating fluorescent dye, and viewed under UV light where they appear as bright orange bands. The other dyes listed are not used to visualise DNA on a gel under UV.
- Q19Which of the following is NOT one of the three key research advances that enabled modern biotechnology?
- Availability of cloning vectors to amplify and join genes
- Discovery of restriction enzymes
- Discovery of DNA polymerase enzymes and cloning techniques
- Invention of the light microscope
Answer: (D) Invention of the light microscope
The three enabling advances were restriction enzymes, cloning vectors, and enzymes like DNA polymerase with gene-cloning methods. The light microscope predates and is unrelated to these molecular advances.
- Q20Under what condition are DNA bands separated by gel electrophoresis visualised?
- Stained with ethidium bromide and exposed to UV light
- Stained with safranin under a microscope
- Stained with iodine in visible light
- Exposed to X-rays without staining
Answer: (A) Stained with ethidium bromide and exposed to UV light
DNA is stained with the intercalating dye ethidium bromide and exposed to UV radiation, where bound DNA appears as bright orange bands. The desired band can then be cut out and eluted.
- Q21The most commonly used type of bioreactor is the:
- Packed-bed reactor
- Photobioreactor
- Trickling filter
- Stirred-tank bioreactor
Answer: (D) Stirred-tank bioreactor
The stirred-tank (and sparged stirred-tank) bioreactor is the most commonly used type. It is usually cylindrical, has an agitator for mixing and oxygen distribution, and controls for temperature, pH, and foam.
- Q22The DNA molecule to which the gene of interest is integrated for cloning is called the:
- vector
- transformer
- template
- carrier
Answer: (A) vector
A vector is the DNA molecule used as a vehicle to carry the foreign gene of interest into a host cell where it is replicated and/or expressed; the resulting molecule is recombinant DNA. ‘Template’ and ‘transformer’ are not used for this carrier role.
- Q23Commonly used vectors for human genome sequencing are:
- T-DNA
- BAC and YAC
- Expression vectors
- T/A cloning vectors
Answer: (B) BAC and YAC
BAC (Bacterial Artificial Chromosome) and YAC (Yeast Artificial Chromosome) carry very large DNA inserts and were the workhorse vectors of the Human Genome Project. T-DNA is for plant transformation; expression and T/A vectors serve other purposes.
- Q24In recombinant DNA technology, antibiotics are used:
- to impart disease-resistance to the host plant
- to keep the medium bacteria-free
- to detect alien DNA
- as selectable markers
Answer: (D) as selectable markers
In rDNA technology, antibiotic-resistance genes act as selectable markers: cells carrying the vector survive on antibiotic-containing medium while non-transformants die, allowing selection of transformants. They are not added to sterilise the medium or confer disease resistance.
- Q25Which of the following is used as a natural vector to deliver genes into plant cells?
- Bacteriophage lambda only
- Retrovirus
- Plasmid pBR322
- Ti plasmid of Agrobacterium tumefaciens
Answer: (D) Ti plasmid of Agrobacterium tumefaciens
The Ti (tumour-inducing) plasmid of Agrobacterium tumefaciens is disarmed and used to deliver genes into plant cells. Retroviruses are used for animal cells; pBR322 and lambda are general bacterial vectors.