ISC Biology Specimen Paper 2026 Class 12: CISCE Biology Sample Paper, Download PDF

Particulars

Details

Conducting Body

Council for the Indian School Certificate Examinations (CISCE)

Exam Name

ISC Class 12 Biology Board Exam 2026

Exam Year

2026

Specimen Paper

ISC Biology Specimen Paper 2026 Class 12

Exam Date

Friday, March 6, 2026

Paper Format

Objective + Subjective Questions

Official website

cisce.org

Question Number

Questions

Marks

SECTION A – 20 MARKS

1

Answer the following questions briefly.

(i) Anita is suffering from dry and scaly lesions on various parts of the body. What is the biological name of the causative fungus?

(ii) If the number of chromosomes in an endosperm is 12, then what will be the number of chromosomes in megaspore mother cell?

(iii) Renu was conducting an experiment. She started with a single DNA strand and ran six cycles of PCR to produce number of molecules of DNA.

(iv) At what stage of embryonic development, can the zygote be introduced in the Fallopian tube in ZIFT? 

(v) When a cross is made between tall plants with yellow seeds (TtYy) and tall plants with green seeds (Ttyy), what proportions of phenotype in the offspring could be expected to be tall plants with green seeds?

(vi) A research scholar isolated a new restriction enzyme from Thermus aquaticus strain YT3. It was the fourth restriction enzyme discovered from this strain. Propose a scientifically accurate name for this enzyme using the standard nomenclature rules. 

(vii) Construct a pyramid of numbers for an ecosystem in which a single large aquatic plant supports a population of small herbivorous fish, which are consumed by a larger population of predatory fish such as kingfish.

(viii) Observe the relation between the first two words and then complete the analogy. [1] Chikungunya: Aedes :: Malaria: ________. 

(ix) A young boy named Arjun has sickle-shaped red blood cells. He experiences frequent fatigue, and shows signs of damage to kidney. Genetic analysis reveals a single point mutation in the gene coding for β-globin. 

Which one of the following genetic phenomena is MOST LIKELY responsible for the multiple symptoms observed in Arjun? 

(a) Polygenic inheritance 

(b) Codominance 

(c) Pleiotropy 

(d) Incomplete dominance

(x) Kiwi is a dioecious species. Which of the following methods can be definitely ruled out as a possible mode of pollination in that case? 

(P) Cleistogamous autogamy 

(Q) Chasmogamous autogamy 

(R) Geitonogamy 

(S) Xenogamy

(a) Only (P) and (R) 

(b) Only (P) and (Q) 

(c) Only (Q) and (S) 

(d) Only (P), (Q) and (R)

(xi) Given below are two statements marked Assertion and Reason. Read both the statements carefully and choose the correct option. 

Assertion: An amino acid in polypeptide chain is not always altered even due to change in the third nitrogenous base of codon. 

Reason: The amino acid does not change due to degeneracy of genetic code. 

(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.

(xii) Given below are two statements marked Assertion and Reason. Read both the statements carefully and choose the correct option. 

Assertion: ‘Bt’ toxin gene has been cloned from bacteria E.coli and expressed in plants to provide resistance from insect without the need of insecticides.

Reason: ‘Bt’ toxin is produced in a crystalline state by the above-mentioned bacterium.

(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.

(xiii) Why are tendrils of vine (Vitis) and pea (Pisum) considered to be analogous organs? 

(xiv) Ravi wanted to grow rice in his field. He was very concerned about environment degradation, so he did not want to use chemical fertilisers. Suggest a suitable biological method to Ravi. 

(xv) Answer the following:  

(a) Expand the abbreviation NPP.

(b) Rule of Equivalence states that in DNA, adenine equals thymine and guanine equals cytosine. This is due to base pairing in double helix. thus, purines equal pyrimidines. Which scientist offered this concept?

(xvi) A bilobed dithecous anther has 100 microspore mother cells per microsporangium. How many male gametophytes can this anther produce?

(xvii) The diagram given below represents a specific stage of gestation period. Identify the structure labelled - B.

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

(a) Sameer drew a diagram of human sperm and showed it to his teacher. The teacher rejected the diagram.

(b) Even under similar environmental conditions, decomposition of the exoskeleton of millipedes occurs more slowly than the leaves.

20

SECTION B – 14 MARKS

2

(i) Construct an ideal pyramid of energy when 1000,000 joules of sunlight is available. Label all its trophic levels.

OR

(ii) The graph given below is based on the data collected from a survey conducted on species richness of a group of mammals in three different climatic regions of the world: Brazil, France and Norway. Brazil has nearly 540 species of mammals, France has nearly 303 species of mammals and Norway has 65 species of mammals.

(a) Based on the species richness, identify the location of these countries in the respective climatic regions shown in the graph. 

(b) In which climatic region, will you place India? 

2

3

Given below is the relationship between the HIV levels in the blood and helper T-cell count in a person detected with AIDS. Study the relationship and answer the questions that follow.

(i) Describe the trend observed between viral load and immune response following initial infection.

(ii) Is the virus permanently eliminated from the body? Justify your answer. 

2

4

As a volunteer for an awareness programme in rural areas, you have been asked to design a poster on sexual health, highlighting birth control options available to males. What two contraceptive methods for males will you highlight in the poster that have negligible chances of failure? Mention the working principle for each method.

2

5

Study the diagram given below and answer the following questions: 

(i) Identify the anode end in the diagram.

(ii) How are these DNA fragments visualised?

2

6

Microbes especially yeasts have been used from time immemorial for the production of beverages like wine, beer, whisky brandy, or rum. Depending on the type of the raw materials used for fermentation and type of processing (with or without distillation) different types of alcoholic drinks are obtained. 

(i) Mention the scientific name of the organism used to prepare fermented beverages. 

(ii) Name any one beverage obtained without distillation of fermented broth.

2

7

(i) Ryan had developed a GM organism. Which government organisation will he approach to obtain the clearance for its mass production?

(ii) Which bioactive product is used for the treatment of emphysema? 

2

8

(i) In a barn, there were 30 rats. 5 more rats entered the barn and 6 of the rats were eaten by the cats in one week. If 8 rats were born during the same period, and during the same time, 7 rats left the barn, find the resultant rat population in the barn at the end of one week. 

(ii) Define carrying capacity. 

2

ISC Biology Specimen Paper 2026 Class 12