CBSE Class 12 Sample Paper 2027 for Biotechnology

FOR CBSE CLASS 12 PREPARATION

CBSE Class 12 Sample
Paper 2027 for
Biotechnology
EXAM YEAR TYPE SUBJECT

CBSE Class 12 2027 Sample Paper Biotechnology

Notes · Sample Papers · Previous Year Papers · Mock Tests

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BIOTECHNOLOGY – CODE NO.la 045
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SAMPLE QUESTION PAPER*
CLASS – XII (2026-27)
Maximum Marks: 70 Time allowed: 3 Hrs

General Instructions:
(i) All questions are compulsory.
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(ii) The question paper has five sections.
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(iii) Section A contains 16 Multiple choice questions of 1 mark each; Section B has 5

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short answer questions of 2 marks each; Section C has 7 short answer questions of
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3 marks each; Section D has two case-based question of 4 marks; Section E has

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three long answer questions of 5 marks each.
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(iv) There is no overall choice. However, internal choices have been provided in some
questions. A student has to attempt only one of the alternatives in such questions.

Q.
SECTION A Marks
No.
1. An organism has 20% of its genome as genes and the genome is divided 1
into four chromosomes. Identify this organism.
A. Arabidopsis thaliana
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B. Humans
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C. Drosophila
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D. Yeast
2.
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Subtilisin is inactivated due to oxidation of amino acid 1
A. histidine
B. methionine
C. aspartate
D. serine
3 The charge relay system in serine proteases helps in 1
A. stabilising the substrate by forming disulfide bonds.
B. activating the serine residue for nucleophilic attack.
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C. lowering the pH of the active site.
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c. o4 D. transporting electrons through the electron transport chain.
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What is the main characteristic of a turbidostat in a continuous microbal 1
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culture system?

g A. Maintains a constant rate of nutrient feed a
a B. Promotes maximum biomass accumulation
C. Increases nutrient supply over time
D. Ensures constant cell concentration
5 Meristem is used as an explant for : 1
A. Obtaining virus resistant plants
B. Promoting somaclonal variations
C. Producing commercially important secondary metabolites

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D. Producing Virus free plants
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6 A student is interested in amplifying a specific region of genome of an 1
organism. Which of the following would actually help her in targeted
amplification?
A. Probes
B. Primers
C. rNTPs
D. ddNTPs
7 There is no increase in the cell concentration in the lag phase due to the 1
following reason -
A. Exhaustion of the medium.
B. Space constraint
C. Accumulation of toxic products
D. Acclimatization to the new environment
8 How does the inclusion of phenol red in many cell culture media 1
demonstrate a practical application of understanding the medium's
properties?
A. Phenol red directly contributes to cell growth by providing essential
nutrients.
B. Phenol red acts as a visual indicator, simplifying pH monitoring and
maintenance of optimal cell culture conditions.
C. Phenol red is essential for maintaining the correct osmolality of the
medium.
D. Phenol red is a necessary cofactor for many enzymatic reactions
within the cell.

9 Somatic embryos are 1
A. identical with zygotic embryos and without seed coats
B. identical with zygotic embryos and with seed coats
C. non-identical with zygotic embryos and without seed coats
D. non-identical with zygotic embryos and with seed coats

10 Which of the following protein pharmaceutical is not produced by CHO cell 1
line?
A. Erythropoietin
B. Factor IX
C. Interleukin 2
D. Monoclonal antibody

11 The correct sequence of steps in the technique of Microarray is: 1
(i) Choosing a cell population
(ii) Conversion to cDNA molecules

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(iii) Extraction of mRNA molecules
(iv) Fluorescent labelling a
(v) Scanning and interpretation
A. (i), (ii), (iv), (iii), (v)
B. (i), (ii), (iii), (v), (vi)
C. (i), (iii), (iv), (ii), (v)
D. (i), (iii), (ii), (iv), (v)

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12 The vectors suitable for transformation of animal cells are: 1
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A. SV 40 vectors and papilloma virus vectors
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B. Cauliflower mosaic virus (CMV) vector and Gemini vectors
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C. Lambda phage and M13 phage vectors
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D. T4 phage vectors
a number 13 to 16, two statements are given one labelled as Assertion (A)
For Questions
and the other labelled as Reason (R). Select the correct answer to these questions from
the codes (A), (B), (C) and (D) as given below.
A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct
explanation of the Assertion (A).
B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct

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explanation of the Assertion (A).

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C. Assertion (A) is true, but Reason (R) is false.

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D. Assertion (A) is false, but Reason (R) is true.
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13 Assertion: Proteins have been engineered to show minimum deleterious 1
effects.
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Reason: Proteins are the main molecules which provide stimulus for
immunity.
14 Assertion: The Somatic cell hybridization offers an excellent alternative 1
for obtaining distant hybrids.
Reason: Somatic hybrids are created by fusing intact cells of distantly
related plants.
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Assertion: Auxins are added to the culture medium if callus induction is
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desired.

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Reason: Nature and quantity of auxin added depends on source of

las explant.
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ag 16 Assertion: Genetic variation between individuals is exploited in DNA 1
fingerprinting.
Reason: Not all genetic variations are useful in DNA fingerprinting.

SECTION B

17 What is specific growth rate in microbial growth kinetics? Write the 2
relation between specific growth rate and doubling time.

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18 Attempt either option A or B. 2

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A. Give any four requirements to carry out the polymerase chain
reaction.
OR
B. Describe any two methods to directly introduce foreign DNA into the
host cells.
19 A researcher is using baffle flasks for small scale microbial culture in the 2
lab. How are baffle flasks different from ordinary flasks?
20 What is protoplast culture? Write any two of its uses. 2
21 Explain the key difference between polyclonal and monoclonal antibodies 2
in terms of their binding specificity to antigens. How does this difference
arise from their cellular origins?
SECTION C
22 A kidney transplant patient is prescribed OKT3 to prevent acute rejection. 3
Explain how OKT3 modifies T-cell activity?

23 Write about any three ways that allow us to perform gene analysis using 3
Bioinformatics.
24 A. Identify the parts of fermenter which are labelled as X, Y and Z. 3

B. “A transgene may be added, which encodes an enzyme to modify a
metabolite produced by the organism to yield a new product of
interest”. Will this be considered as strain improvement? Justify giving
an example.
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A. What is the capacity of a small scale biofermentor used in
laboratories? Mention any two uses of such bioreactors.
B. “A transgene may be added, which encodes an enzyme to modify a

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a improvement? Justify
metabolite produced by the organism to yield
interest”. Will this be considered as strain
giving an example.
Attempt either option A or B. 3
25 A. A group of Indian scientists observed that group of patients feeding
on whey are responding better to retro-viral therapy as compared to
those who are not taking it. What could be the possible scientific
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explanation for this therapeutic effect?
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OR
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B. Write about the three parameters that define the dietary value of
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proteins.
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A. Illustrate the steps involved in the generation of RFLP.
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B. What is the RFLP pattern expected in case of identical twins.
27 3

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Look at the diagram and answer the following questions
A. Derive at the original DNA sequence by reading above given
autoradiogram.
B. Why are ddNTPs used along with dNTPs in the enzymatic
method of DNA sequencing?
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C. How is a dNTP chemically different from a ddNTP?

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The sequence of the strand of DNA complementary to the
a strand is
5’ ACGCCCGAGTAGCCCAGA 3’
A. Write the sequence of the original strand.
B. Which method is commonly used to sequence DNA?
C. Why is automated DNA sequencing considered safer?

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28 3

A. Based on the visual cues, Identify the technique which is depicted
here?
B. Expand ICM. From which developmental stage is it obtained, and
why is this stage ideal for pluripotency research?
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A. Differentiate between finite and continuous cell lines based on their
lifespan in culture.
B. Herceptin is a monoclonal antibody used to treat HER2 - positive
breast cancer. Based on the information provided, what is the role of
the HER2 receptor in cancer cell growth, and how does Herceptin
interfere with this process to inhibit cancer progression?
SECTION D
29 Chronic Myelogenous Leukemia is caused due to Reciprocal translocation 4
mutation between chromosome 9 and 22 that forms an extra-long
chromosome 9 and extra small chromosome 22 containing the fused
gene regions. Refer to the schematic view representing metaphase
chromosome and answer the question that follow:

A. Identify the gene region P and Q in the given diagram.
B. What is the extra small resultant chromosome 22 called?
Attempt either subpart C or D.
C. Apart from Karyotyping, which other technique can be used to
detect CML in patients? State the principle of the technique.
OR
D. Why is Karyotyping not, a preferred method to find out the severity
of CML disease?
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For Visually impaired students
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Chronic Myelogenius Leukemia is caused due to reciprocal translocation
between chromosome 9 and 22 that forms an extra-long chromosome 9
and an extra small chromosome 22 containing the fused gene regions.
Both the chromosomes are metaphase arrested and visible during
Karyotyping. Answer the questions that follow:
A. What are the names given to both the gene regions of chromosome
9 and 22 that fuse?
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B. What is the extra small chromosome 22 known as?
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Attempt either subpart C or D.
mfrom Karyotyping, which other technique can be used to las e m
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C. Aparte g
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detect CML in patients? What is its principle?
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D. Why is Karyotyping not, a preferred method to find out the severity
of CML disease?
30 Mass spectrometry 4

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(MS) has emerged as an important tool for characterisation. A protein with
a molecular weight of 10,000 dalton generates five different peaks with
the ions containing 5, 4, 3, 2, and 1 charges, respectively, as shown
below.
A. What happens if there is a loss of charge from a biomolecule?
B. Mass spectrometry is an analytical tool. Justify the statement.
Attempt either subpart C or D.
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the m/z ratio each for protein ions containing 4 and.2
c. o C. Calculate s e m
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charges.
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OR

ag D. A protein has a molecular weight of 20,000 daltons and it forms two
protein ions containing 6 and 7 charges, what will be its
mass/charge ratio?
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Mass spectrometry (MS) has emerged as an important tool in
biotechnology. It is extremely useful in obtaining protein structural

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information such as peptide mass or amino acid sequences. The
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molecular ions are generated either by a loss or gain of a charge (e.g.
electron ejection, protonation or deprotonation). After the ions are formed,
they can be separated according to their m/z ratio and finally detected.
A. What happens if there is a loss of charge from a biomolecule? Give
two reasons.
B. Mass spectrometry is an analytical tool. Justify the statement.
Attempt either subpart C or D.
C. Name the major components of a mass spectrometer.
OR
D. How is MALDI used to volatilize and protonate proteins?
SECTION E
31 Attempt either option A or B. 5
A. Few restriction enzymes break the phosphodiester bond in such a
manner that single stranded overhang ends are generated in the DNA
strand. EcoRI is one such a restriction enzyme.
I. Write the sequence for restriction site for enzyme EcoRI. Give a
name to the kind of ends generated here.
II. If the following DNA strand is digested by EcoRI, how many DNA
fragments will be generated. Write the sequence of these double
stranded DNA fragments with their respective polarity.
5’ GTATTAGCTGAATTCTATAAAACG 3’
3’ CATAATCGACTTAAGATATTTTGC 5’
III. Why is EcoRI named so?
OR
B. A gene X was introduced into cloning vector pUC19 at LacZ gene site.
What will be the impact on the recombinant plasmids? Also suggest a
possible way by which we can differentiate recombinants from non-
recombinant plasmids.
32 Attempt either option A or B. 5
A.
I. A company plans to release a new insect-resistant GM crop.
Evaluate three potential bioethical concerns in plant genetic
engineering.
II. What was the need to develop “Flavr Savr”?
OR
B.
I. How can the transgenic plants be used as factories to produce
biodegradable plastics?
II. What are artificial seeds and mention any one application? Explain
diagrammatically.

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33 Attempt either option A or B.
A.
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I. Describe the technique developed by O’farrell to study proteomics.
II. Name any two properties that can be manipulated using protein
Engineering.
OR
B.
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I. Why is sickle cell anaemia called a molecular disease?
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II. Who developed peptide mapping? Describe the technique.
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