Class XII · Biology practice

Biotechnology Principles and Processes PYQs

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39 questions in this collection · Page 2 of 4

Question 11 of 39
🟢 NEET 2021 📘 CLASS XII

Biotechnology Principles And Processes

During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out:
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Question 12 of 39
🟢 NEET 2021 📘 CLASS XII

Biotechnology Principles And Processes

DNA strands on a gel stained with ethidium bromide when viewed under UV radiation, appear as:
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Question 13 of 39
🟢 NEET 2021 📘 CLASS XII

Biotechnology Principles And Processes

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

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Explanation:

In pBR322, the ampR gene provides ampicillin resistance. If PstI cuts within ampR to insert a β-galactoside gene, ampR is disrupted, so the plasmid can no longer confer ampicillin resistance. Therefore, transformed E. coli would not survive ampicillin unless ampR remains functional. Hence, option 1 is correct. Options 2 and 4 assume both resistance and new function, which is unlikely when ampR is inactivated by insertion. Option 3 about lysis is not a general consequence of such recombination.

🧠 Did You Know?

In blue-white screening, insertion of a foreign gene into lacZ (β-galactosidase gene) often disrupts beta-galactosidase production, helping identify recombinant colonies.

💡 NCERT Memory Line:

Restriction enzymes create cuts at specific sites; inserting foreign DNA into a plasmid can disrupt a gene (e.g., ampR) and alter antibiotic resistance.

Question 14 of 39
🟢 NEET 2021 📘 CLASS XII

Biotechnology Principles And Processes

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?
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Question 15 of 39
🟢 NEET 2021 📘 CLASS XII

Biotechnology Principles And Processes

A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is:
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Question 16 of 39
🟢 NEET (Oct)2020 📘 CLASS XII

Biotechnology Principles And Processes

Match the following techniques or instruments with their usage:
Column-I Column-II
(A)Bioreactor (I)Separation of DNA fragments
(B)Electrophoresis (II)Production of large quantities of products
(C)PCR (III)Detection of pathogen, based on antigen - antibody reaction
(D)ELISA (IV)Amplification of nucleic acids
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Question 17 of 39
🟢 NEET (Oct)2020 📘 CLASS XII

Biotechnology Principles And Processes

First discovered restriction endonuclease that always cuts DNA molecule at a particular point by recognising a specific sequence of six base pairs is:
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Question 18 of 39
🟢 NEET (Oct)2020 📘 CLASS XII

Biotechnology Principles And Processes

Select the correct statement from the following:

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Explanation:

Option 3 is correct. Restriction enzyme digestions involve incubating purified DNA with restriction enzymes under optimum conditions to cut DNA at specific sequences. This is a standard step in gene cloning as per NCERT.

🧠 Did You Know?

Gel electrophoresis (option 1) is for separating DNA fragments, not amplifying them. PCR (option 4) amplifies DNA, not isolates or separates it. Ligation by DNA ligase (not listed) joins gene and vector (a different process from what PCR or restriction digestion does).

💡 NCERT Memory Line:

Restriction enzymes cut DNA at specific sites; PCR amplifies target DNA segments; gel electrophoresis separates DNA fragments by size.

Question 19 of 39
🟢 NEET (Oct)2020 📘 CLASS XII

Biotechnology Principles And Processes

In a mixture, DNA fragments are separated by:
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Question 20 of 39
🟢 NEET (Oct)2020 📘 CLASS XII

Biotechnology Principles And Processes

In Recombinant DNA technology antibiotics are used:

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Explanation:

In recombinant DNA technology, antibiotics are used as selectable markers. Bacteria that have taken up the recombinant plasmid usually carry an antibiotic resistance gene. When grown on a medium containing the antibiotic, only those cells with the plasmid survive, enabling easy identification of successful transformants.

🧠 Did You Know?

Selectable markers help distinguish cells that have incorporated the desired DNA from those that have not.

💡 NCERT Memory Line:

Antibiotics in the culture medium select only the transformed cells that contain the marker gene.

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