Biotechnology: Principles and Processes — NEET Botany MCQs with answers

Biotechnology: Principles and Processes is a Class 12 Botany chapter in the NEET (UG) syllabus. NEET720 has 757 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.

Topics covered

Tools of Recombinant DNA Technology · Techniques · Processes of Recombinant DNA Technology · Principles and Processes · Applications · Principles of Biotechnology · Principles of Biotechnology · Tools of Recombinant DNA Technology · Processes of Recombinant DNA Technology · Applications of Biotechnology · Human Welfare/Biotechnology · Biotechnology · Recombinant DNA technology · Restriction enzymes · Cloning vectors · Gene cloning vectors · Gene transfer methods · PCR steps · Elution · Competent cells · Bioreactors · Cloning history · Cutting and joining DNA · Genomic vs cDNA libraries · Human insulin production · Molecular scissors · Selectable markers · Molecular diagnostics · Exonuclease vs endonuclease · Vector requirements · Multiple cloning site · Chromatography · Isolation of DNA · Precipitation of DNA · Cloning site placement · Restriction enzyme applications · Recombinant protein production organisms · Amplification via cloning · DNA extraction obstacles · Concept of transformation

8 free Biotechnology: Principles and Processes practice questions with answers

Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.

1. Question 1 · easy · Processes of Recombinant DNA Technology

   Arrange the following steps of recombinant DNA technology in the correct order in which they are normally carried out: (i) Cutting of DNA at specific locations, (ii) Isolation of DNA, (iii) Insertion of recombinant DNA into the host, (iv) Ligation of DNA fragment with vector.

   • A.(ii) → (i) → (iv) → (iii)
   • B.(i) → (ii) → (iii) → (iv)
   • C.(ii) → (iv) → (i) → (iii)
   • D.(iv) → (ii) → (i) → (iii)
   Show answer and explanation

   Answer: A. (ii) → (i) → (iv) → (iii)

   The process begins with isolating DNA from the cell, then cutting it with restriction enzymes, then ligating it with a vector to form recombinant DNA, and finally inserting this into a host cell.

   The logical and experimental order of rDNA technology is: isolation of genetic material (DNA must first be obtained in pure form) → cutting of DNA and vector using the same restriction enzyme to generate compatible ends → ligation of the gene of interest with the vector DNA using DNA ligase to form the recombinant DNA → insertion of this recombinant DNA into a host cell/organism for propagation and expression. Any order that cuts or ligates before isolation, or ligates before cutting, is biologically impossible since you cannot cut or join a molecule that has not first been obtained.

   Common mistake: Students sometimes think cutting or ligation can precede isolation of DNA from the cell.

   Key point: rDNA technology always proceeds: isolate DNA → cut with restriction enzyme → ligate into vector → insert into host.

2. Question 2 · medium · Processes of Recombinant DNA Technology

   Which enzyme is used to break open a bacterial cell wall as the first step in isolating its DNA?

   • A.Cellulase
   • B.Lysozyme
   • C.Chitinase
   • D.Ribonuclease
   Show answer and explanation

   Answer: B. Lysozyme

   Lysozyme digests the peptidoglycan layer of bacterial cell walls, releasing the cell contents including DNA.

   Different organisms have differently composed cell walls, so different lytic enzymes are used to break them open: lysozyme for bacteria (peptidoglycan wall), cellulase for plant cells (cellulose wall), and chitinase for fungi (chitin wall). Ribonuclease and protease act later in the isolation process to remove RNA and protein contaminants respectively, not to lyse the cell wall.

   Common mistake: Confusing lysozyme (bacteria) with cellulase (plants) or chitinase (fungi).

   Key point: Lysozyme–bacteria, cellulase–plant, chitinase–fungi: match the lytic enzyme to the cell wall it digests.

3. Question 3 · medium · Processes of Recombinant DNA Technology

   A researcher wants to isolate DNA from a fungal culture. Which enzyme should be used to break open the fungal cell wall?

   • A.Lysozyme
   • B.Cellulase
   • C.Chitinase
   • D.Protease
   Show answer and explanation

   Answer: C. Chitinase

   Fungal cell walls are made of chitin, so chitinase is used to lyse fungal cells during DNA isolation.

   Since fungal cell walls are composed mainly of chitin, chitinase is the appropriate enzyme to degrade the wall and release cellular contents for DNA isolation. Lysozyme acts on bacterial peptidoglycan, cellulase acts on plant cellulose, and protease removes contaminating proteins after lysis rather than breaking the wall.

   Common mistake: Applying lysozyme or cellulase to fungal cells instead of chitinase.

   Key point: Chitinase is specific to fungal (chitin) cell walls during DNA isolation.

4. Question 4 · easy · Processes of Recombinant DNA Technology

   Why must DNA be isolated in a relatively pure form before it can be cut with restriction enzymes?

   • A.Because restriction enzymes cannot recognise DNA that is inside an intact nucleus, regardless of contaminants
   • B.Because impure DNA is always double the correct molecular weight
   • C.Because unpurified DNA cannot be visualised under UV light at all
   • D.Because DNA exists in the cell along with other macromolecules such as RNA, proteins, polysaccharides and lipids that must be removed before manipulation
   Show answer and explanation

   Answer: D. Because DNA exists in the cell along with other macromolecules such as RNA, proteins, polysaccharides and lipids that must be removed before manipulation

   DNA in the cell is associated with RNA, proteins and other macromolecules, so it must be purified before enzymatic manipulation.

   Inside the cell nucleus, DNA coexists with RNA, proteins, polysaccharides and lipids. To manipulate DNA with restriction enzymes and other tools, it must first be obtained free of these other cellular components in a relatively pure form. This is achieved by lysing the cell, then treating the lysate with RNase to remove RNA and protease to remove proteins, followed by purification steps such as ethanol precipitation.

   Common mistake: Believing enzymes cannot act on DNA inside the nucleus rather than understanding the contamination issue.

   Key point: DNA must be freed from RNA, protein and other macromolecules before it can be enzymatically manipulated.

5. Question 5 · medium · Processes of Recombinant DNA Technology

   Statement I: RNA present in the cell lysate is removed by treatment with the enzyme ribonuclease. Statement II: Proteins associated with DNA are removed by treatment with protease enzymes. In light of the above statements, choose the most appropriate answer.

   • A.Both Statement I and Statement II are correct
   • B.Statement I is correct but Statement II is incorrect
   • C.Statement I is incorrect but Statement II is correct
   • D.Both Statement I and Statement II are incorrect
   Show answer and explanation

   Answer: A. Both Statement I and Statement II are correct

   Both statements correctly describe standard steps in DNA isolation: RNase removes RNA and protease removes protein contaminants.

   After cell lysis, the crude extract contains DNA along with RNA and proteins. Ribonuclease (RNase) specifically degrades RNA, while protease enzymes degrade protein, allowing these contaminants to be separated from DNA during subsequent purification. Both processes are essential and factually accurate steps of DNA isolation as described in the rDNA technology workflow.

   Common mistake: Assuming only one of RNA or protein removal is enzymatically achieved, or confusing RNase with restriction enzymes.

   Key point: RNase removes RNA; protease removes protein — both are used to purify DNA before it can be manipulated.

6. Question 6 · medium · Processes of Recombinant DNA Technology

   After treatment with lytic enzymes, RNase and protease, purified DNA is finally precipitated out of solution by the addition of:

   • A.Warm distilled water
   • B.Chilled ethanol
   • C.Concentrated hydrochloric acid
   • D.Restriction endonuclease buffer
   Show answer and explanation

   Answer: B. Chilled ethanol

   Chilled ethanol is added to the purified aqueous DNA solution, causing the DNA to precipitate out as visible fine threads.

   Once RNA, proteins and other macromolecules have been removed, purified DNA can be precipitated by adding chilled ethanol. The DNA becomes insoluble in the ethanol–water mixture and precipitates out, appearing as fine collected threads that can be spooled out with a glass rod — a hallmark visual step of DNA isolation protocols.

   Common mistake: Confusing the precipitation step with cutting/ligation steps that come later in the process.

   Key point: Chilled ethanol precipitates purified DNA, which appears as fine collected threads.

7. Question 7 · medium · Processes of Recombinant DNA Technology

   In the standard sequence of recombinant DNA technology, which step immediately follows the cutting of DNA at specific locations using restriction enzymes (assuming PCR amplification is not used in this particular protocol)?

   • A.Isolation of DNA from the cell
   • B.Obtaining the desired product from the host organism
   • C.Insertion of recombinant DNA into the host cell
   • D.Ligation of the DNA fragment with a vector to form recombinant DNA
   Show answer and explanation

   Answer: D. Ligation of the DNA fragment with a vector to form recombinant DNA

   After cutting DNA with restriction enzymes, the fragment is ligated with a vector to form recombinant DNA, before insertion into a host.

   Once DNA has been cut at specific locations with restriction enzymes (and optionally amplified by PCR), the resulting DNA fragment of interest is joined (ligated) with vector DNA using DNA ligase to form recombinant DNA. This recombinant DNA is only afterward inserted into a host cell. Skipping straight to insertion or to obtaining the product without ligation is not possible.

   Common mistake: Jumping ahead in the sequence and assuming host insertion or product recovery happens right after cutting.

   Key point: Cutting DNA is always followed by ligation into a vector, never directly by host insertion or product recovery.

8. Question 8 · easy · Processes of Recombinant DNA Technology

   Before it can be manipulated using biotechnology tools, DNA must first be isolated because inside the cell it exists:

   • A.In the nucleus along with other macromolecules such as RNA, proteins, polysaccharides and lipids
   • B.Freely dissolved outside the cell in the surrounding medium
   • C.Only as free nucleotides that must first be polymerised before isolation
   • D.Bound irreversibly to the restriction enzyme that will later cut it
   Show answer and explanation

   Answer: A. In the nucleus along with other macromolecules such as RNA, proteins, polysaccharides and lipids

   DNA exists within the cell nucleus alongside other macromolecules, so it must be isolated and purified before manipulation.

   Because DNA in vivo is intimately associated with RNA, proteins, polysaccharides and lipids within the cell (largely in the nucleus in eukaryotes), it must be released from the cell and purified away from these other components before it can be cut, ligated or otherwise manipulated using biotechnology tools.

   Common mistake: Overlooking that DNA purification is required simply because of its cellular context, not any inherent property of DNA itself.

   Key point: DNA isolation is necessary because DNA naturally coexists with RNA, protein and other macromolecules in the cell.

Questions about Biotechnology: Principles and Processes for NEET

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