ISC Class 12 Biology Specimen Paper 2026-27: Download PDF for CISCE Board Exam

Category

Details

Conducting Body

Council for the Indian School Certificate Examinations (CISCE)

Exam Name

ISC Class 12 Biology

Academic Session

2026–27

Exam Date

To be announced 

Paper Type

Theory

Total Marks

70 Marks (Internal Assessment: 30 Marks)

Exam Duration 

3 Hours

Official Website

cisce.org

Question 1

(i) Stuti ate a cake containing nuts and immediately developed swelling of the lips and difficulty in breathing. Identify the chemical responsible for Stuti’s condition. 
(a) Insulin
(b) Histamine
(c) Interferon
(d) Adrenaline

(ii) A survey was conducted to study the age structure of a human population. The data obtained is shown below:

Based on the above data, identify the MOST appropriate shape of the age pyramid for this population.
(a) Pyramidal
(b) Triangular
(c) Urn-shaped
(d) Bell-shaped

(iii) In a single-stranded segment of a DNA molecule, the base ratio (A+T):(G+C) is found to be 0∙3:1. What will be the ratio (A + G):(T + C) for the entire double-stranded DNA molecule?
(a) 1:1
(b) 3:10
(c) 10:3
(d) 13:3

(iv) Identify the vectors used for cloning genes into eukaryotic organisms.
(P) BAC
(Q) Bacteriophages
(R) Ti plasmid
(S) Disarmed retroviruses
(a) Only (P) and (Q)
(b) Only (P) and (R)
(c) Only (Q) and (S)
(d) Only (R) and (S)

(v) In an ecosystem, interspecific interaction of population is explained through certain signs. (+) sign is assigned for beneficial interaction, (-) sign is assigned for harmful interaction, and (0) is assigned for neutral interaction. Which of the following represents amensalism
(a) Species A (-), Species B (0)
(b) Species A (+), Species B (+)
(c) Species A (-), Species B (-)
(d) Species A (+), Species B (0)

(vi) Given below are two statements marked Assertion and Reason. Read both the statements carefully and choose the correct option.
Assertion: Excess dose of cocaine produces a sense of euphoria, increased energy and hallucinations.
Reason: Cocaine interferes with the transport of dopamine leading to abnormalities in the brain. 

(a) Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
(c) Assertion is true and Reason is false.
(d) Both Assertion and Reason are false.

(vii) Given below are two statements marked Assertion and Reason. Read both the statements carefully and choose the correct option.
Assertion: In a majority of flowering plants, the embryo sac development is called monosporic.
Reason: Embryo sac develops from one of the two megaspores formed by meiosis of megaspore mother cell.

(a) Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
(b) Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
(c) Assertion is true and Reason is false.
(d) Both Assertion and Reason are false.

(viii) A patient was found to have a mass of pancreatic cells in the liver producing large
amounts of amylase. Further medical tests revealed a tumor in the pancreas. What type of tumour had developed in the pancreas?

(ix) A research scholar isolated a novel restriction enzyme from Bacillus anthracis strain ZT4. It was the third restriction enzyme to be extracted from this specific
strain. Derive the scientific name for this enzyme by applying the standard rules of biological nomenclature.

(x) Why do leguminous crops fertilise the soil but cereals do not?

(xi) The pie chart given below represents the extent of global biodiversity of invertebrates.

Which specific phylum of invertebrates does ‘B’ represent?

(xii) Construct an ecological pyramid of biomass for the following food chain: Grass → Deer → Fleas

(xiii) Observe the relation between the first two words and complete the analogy.

Sigma factor: Initiation :: __________________: Termination

(xiv) A retroviral RNA undergoes reverse transcription to produce a double-stranded DNA molecule containing a six-nucleotide-long palindromic sequence. A partial segment of this double-stranded DNA is shown below:
5′– GGA --- – 3′
3′– --- --- --- – 5′
Obtain the six nucleotide long palindromic DNA sequence on the 3′ – 5′ strand of DNA.

(xv) A rural area has a population density of 150 individuals per sq. km. If the area is 250 sq. km, what will be the total population of the rural area?

(xvi) Answer the following:
(a) Expand the abbreviation KVIC.
(b) Alexander Fleming had discovered an antibiotic which was later successfully purified by a team of scientists and used to save countless lives. Name the scientists who purified it and established it as a lifesaving drug.

(xvii) State the underlying principle of ELISA test.

(xviii) Give a reason for each of the following statements:

(a) Our government has imposed strict conditions and regulations on Medical Termination of Pregnancy.
(b) In the biolistic method of gene transfer, microparticles are preferred to be made of gold rather than copper

SECTION B – 14 MARKS

Question 2

The image shown below represents an ecological hypothesis proposed by Paul Ehrlich. Study it carefully and answer the following question.

Identify and explain this ecological hypothesis. 

Question 3

An alien gene was ligated by a research scholar at Sal I site of pBR322 plasmid. It affected a selectable marker.
(i) Name the selectable marker which was affected. 

Question 4

A scientist retrieved an embryo from the uterus of a human female just after implantation for the purpose of cloning.

(i) Identify the specific stage of the embryonic development at which the scientist retrieved it.
(ii) Which part of the embryo referred to in subpart (i) is most suitable for cloning?

Question 5

Study the following Venn diagram and answer the questions that follow.

(i) Which contraceptive method occupies the shaded region in the given Venn diagram?
(ii) How does Multiload – 375 function as a contraceptive agent?

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To download complete Question Paper PDF along with marking scheme for ISC Class 12 Biology Specimen Paper 2027 for board exams. Students can tap on the link below and get the PDF for free to download and start their prepration in advance to score good grades in 2027 board exams. 

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