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Biotechnology Principles and Processes: questions with answers

Class 12 Biology, Chapter 9 (NCERT). 15 questions by concept. Open “Show answer” for the answer and why.

How to teach this chapter · Common misconceptions & worked visual for this chapter

Core principles of biotechnology

Question 1

Which statement best explains core principles of biotechnology?

  1. (a)The process has no biological mechanism and never depends on evidence.
  2. (b)Modern biotechnology combines genetic engineering with maintained sterile conditions for large-scale culture and product recovery; both molecular design and process engineering are required.
  3. (c)Genetic engineering alone guarantees an industrial product
  4. (d)Biotechnology is only traditional fermentation
Show answer

(b) Modern biotechnology combines genetic engineering with maintained sterile conditions for large-scale culture and product recovery; both molecular design and process engineering are required.

Modern biotechnology combines genetic engineering with maintained sterile conditions for large-scale culture and product recovery; both molecular design and process engineering are required.

Question 2

A learner claims: Biotechnology is only traditional fermentation. Which correction is best?

  1. (a)Biotechnology is only traditional fermentation
  2. (b)The claim is correct because all biological systems behave identically.
  3. (c)Modern biotechnology includes deliberate DNA manipulation and controlled bioprocessing.
  4. (d)Genetic engineering alone guarantees an industrial product
Show answer

(c) Modern biotechnology includes deliberate DNA manipulation and controlled bioprocessing.

Modern biotechnology includes deliberate DNA manipulation and controlled bioprocessing.

Gel electrophoresis and elution

Question 3

Which statement best explains gel electrophoresis and elution?

  1. (a)DNA migrates toward the negative electrode
  2. (b)Negatively charged DNA migrates through agarose toward the positive electrode; smaller fragments generally move farther. A desired band can be cut out and eluted for later steps.
  3. (c)Larger fragments always move faster through agarose
  4. (d)The process has no biological mechanism and never depends on evidence.
Show answer

(b) Negatively charged DNA migrates through agarose toward the positive electrode; smaller fragments generally move farther. A desired band can be cut out and eluted for later steps.

Negatively charged DNA migrates through agarose toward the positive electrode; smaller fragments generally move farther. A desired band can be excised and eluted for later steps.

Question 4

A learner claims: DNA migrates toward the negative electrode. Which correction is best?

  1. (a)Larger fragments always move faster through agarose
  2. (b)The claim is correct because all biological systems behave identically.
  3. (c)DNA migrates toward the negative electrode
  4. (d)The phosphate backbone makes DNA migrate toward the positive electrode.
Show answer

(d) The phosphate backbone makes DNA migrate toward the positive electrode.

The phosphate backbone makes DNA migrate toward the positive electrode.

Restriction enzymes and recognition sites

Question 5

How does a restriction endonuclease locate a palindromic recognition site in double-stranded DNA?

  1. (a)Measuring a fixed distance from an end of the DNA
  2. (b)Matching identical sequences read left to right on the two aligned strands
  3. (c)Selecting a position at random, regardless of sequence
  4. (d)Matching a specific sequence read 5′ to 3′ on each strand
Show answer

(d) Matching a specific sequence read 5′ to 3′ on each strand

A restriction endonuclease recognises a specific base sequence. At a palindromic site, both strands give the same sequence when each is read 5′ to 3′.

Question 6

What products result when many identical linear DNA molecules, each containing two internal EcoRI sites, undergo complete digestion with EcoRI?

  1. (a)Each molecule stays uncut
  2. (b)Three fragments of fixed lengths from each molecule
  3. (c)Fragments of randomly varying lengths from each molecule
  4. (d)Two fragments of fixed lengths from each molecule
Show answer

(b) Three fragments of fixed lengths from each molecule

EcoRI cuts each identical molecule at the same two recognition sites. Two internal cuts in linear DNA produce three fragments with fixed lengths.

Cloning-vector architecture

Question 7

Which statement best explains cloning-vector architecture?

  1. (a)A vector needs no origin of replication
  2. (b)Selectable markers directly identify DNA sequence without selection
  3. (c)The process has no biological mechanism and never depends on evidence.
  4. (d)A useful vector carries an origin of replication, selectable marker and suitable cloning site; copy number, host range and insertional inactivation affect recovery of recombinants.
Show answer

(d) A useful vector carries an origin of replication, selectable marker and suitable cloning site; copy number, host range and insertional inactivation affect recovery of recombinants.

A useful vector carries an origin of replication, selectable marker and suitable cloning site; copy number, host range and insertional inactivation affect recovery of recombinants.

Question 8

A learner claims: A vector needs no origin of replication. Which correction is best?

  1. (a)The claim is correct because all biological systems behave identically.
  2. (b)Selectable markers directly identify DNA sequence without selection
  3. (c)The origin permits autonomous replication and influences copy number.
  4. (d)A vector needs no origin of replication
Show answer

(c) The origin permits autonomous replication and influences copy number.

The origin permits autonomous replication and influences copy number.

Competent hosts and DNA uptake

Question 9

Which statement best explains competent hosts and dna uptake?

  1. (a)All transformants necessarily contain the desired insert
  2. (b)Cells can be made competent by chemical treatment, heat shock, electroporation or biological delivery. Uptake creates transformants, but selection and confirmation are needed to identify desired recombinants.
  3. (c)Every untreated cell takes up naked DNA efficiently
  4. (d)The process has no biological mechanism and never depends on evidence.
Show answer

(b) Cells can be made competent by chemical treatment, heat shock, electroporation or biological delivery. Uptake creates transformants, but selection and confirmation are needed to identify desired recombinants.

Cells can be made competent by chemical treatment, heat shock, electroporation or biological delivery. Uptake creates transformants, but selection and confirmation are needed to identify desired recombinants.

Question 10

A learner claims: Every untreated cell takes up naked DNA efficiently. Which correction is best?

  1. (a)Competence or a delivery method is usually required for efficient uptake.
  2. (b)The claim is correct because all biological systems behave identically.
  3. (c)Every untreated cell takes up naked DNA efficiently
  4. (d)All transformants necessarily contain the desired insert
Show answer

(a) Competence or a delivery method is usually required for efficient uptake.

Competence or a delivery method is usually required for efficient uptake.

DNA isolation and controlled cutting

Question 11

Which statement best explains dna isolation and controlled cutting?

  1. (a)Restriction digestion works independently of buffer and temperature
  2. (b)The process has no biological mechanism and never depends on evidence.
  3. (c)DNA isolation should leave nucleases active
  4. (d)Intact DNA is released by breaking membranes and removing proteins, RNA and other contaminants; purified DNA and vector are cut under compatible enzyme conditions.
Show answer

(d) Intact DNA is released by breaking membranes and removing proteins, RNA and other contaminants; purified DNA and vector are cut under compatible enzyme conditions.

Intact DNA is released by breaking membranes and removing proteins, RNA and other contaminants; purified DNA and vector are cut under compatible enzyme conditions.

Polymerase chain reaction

Question 12

Which statement best explains polymerase chain reaction?

  1. (a)Denaturation is the DNA-synthesis step
  2. (b)PCR cycles through denaturation, primer annealing and thermostable-polymerase extension to amplify the sequence between two primers exponentially when reagents and target are suitable.
  3. (c)The process has no biological mechanism and never depends on evidence.
  4. (d)PCR amplifies every DNA sequence equally without primers
Show answer

(b) PCR cycles through denaturation, primer annealing and thermostable-polymerase extension to amplify the sequence between two primers exponentially when reagents and target are suitable.

PCR cycles through denaturation, primer annealing and thermostable-polymerase extension to amplify the sequence between two primers exponentially when reagents and target are suitable.

Bioreactor design and control

Question 13

Which statement best explains bioreactor design and control?

  1. (a)A bioreactor is merely a larger unmonitored flask
  2. (b)Maximum foam always improves oxygen transfer
  3. (c)Stirred-tank bioreactors maintain mixing, aeration, pH, temperature, foam control and sampling so cells experience reproducible growth and production conditions at scale.
  4. (d)The process has no biological mechanism and never depends on evidence.
Show answer

(c) Stirred-tank bioreactors maintain mixing, aeration, pH, temperature, foam control and sampling so cells experience reproducible growth and production conditions at scale.

Stirred-tank bioreactors maintain mixing, aeration, pH, temperature, foam control and sampling so cells experience reproducible growth and production conditions at scale.

Downstream processing and quality

Question 14

Which statement best explains downstream processing and quality?

  1. (a)Crude broth can be used directly as every medicine
  2. (b)Downstream processing ends when cells finish growing
  3. (c)After biosynthesis, a product is separated, purified, formulated and quality-tested. Standards depend on the intended use. Therapeutics need especially strict purity and sterility.
  4. (d)The process has no biological mechanism and never depends on evidence.
Show answer

(c) After biosynthesis, a product is separated, purified, formulated and quality-tested. Standards depend on the intended use. Therapeutics need especially strict purity and sterility.

After biosynthesis, a product is separated, purified, formulated and quality-tested; standards depend on the intended use, with therapeutics requiring especially stringent purity and sterility.

Ligation, transformation and screening

Question 15

Which statement best explains ligation, transformation and screening?

  1. (a)DNA ligase cuts at recognition sites
  2. (b)The process has no biological mechanism and never depends on evidence.
  3. (c)Antibiotic resistance proves that the desired insert is present
  4. (d)DNA ligase joins compatible vector and insert ends. The ligation mixture is introduced into competent cells, selected for vector uptake and screened to distinguish recombinant clones.
Show answer

(d) DNA ligase joins compatible vector and insert ends. The ligation mixture is introduced into competent cells, selected for vector uptake and screened to distinguish recombinant clones.

DNA ligase joins compatible vector and insert ends. The ligation mixture is introduced into competent cells, selected for vector uptake and screened to distinguish recombinant clones.

Common misconception in Biotechnology Principles and Processes

Open full misconception guide →

Does antibiotic survival prove the target gene is present?

Wrong

Every colony that grows on the antibiotic must contain the desired DNA insert.

Why it feels right. I assume the selection step tests the entire cloning result.

Right

A resistance marker selects for the marker. A separate check can confirm the insert.

Worked example

Empty plasmid
Marker retained→Colony grows→Shorter PCR product
Plasmid with insert
Marker retained→Colony grows→Longer PCR product
The resistance marker allows both plasmids to pass selection. PCR can then distinguish different insert sizes.
  1. If a plasmid retains its resistance marker whether or not it has an insert, cells with either plasmid can grow.
  2. A PCR test spanning the insertion site can distinguish the two by product size.