ICSE question bank

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108 questions

Class 12 · Biology
3] A scientist is attempting to create a recombinant DNA molecule by combining a plasmid vector and a foreign DNA. A plasmid DNA and a linear DNA of the same size have a single site for the restriction enzyme EcoRI. When cut by the same RE and separated by gel electrophoresis, the plasmid shows one DNA band, and the linear DNA shows two bands.
What causes the difference between the number of DNA bands generated from
the plasmid and from the linear DNA?
Short answer
Class 12 · Biology
(a) The recessive allele ‘b’ occurs with a frequency of 0·8 in a population of
moths that is in Hardy Weinberg Equilibrium. What is the frequency of
homozygous dominant individuals?
(b) List any two differences between Homo habilis and Homo erectus.
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ISC (CLASS XII) SPECIMEN QUESTION PAPER 2026
Short answer
Class 12 · Biology
2] 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.
Mention the scientific name of the organism used to prepare fermented beverages.
Short answer
Class 12 · Biology
3] Study the pedigree chart given below showing the pattern of blood group inheritance in a family.
State the possible blood group(s) of the individual ‘Y’ in 3rd generation.
Short answer
Class 12 · Biology
3] A scientist is attempting to create a recombinant DNA molecule by combining a plasmid vector and a foreign DNA. A plasmid DNA and a linear DNA of the same size have a single site for the restriction enzyme EcoRI. When cut by the same RE and separated by gel electrophoresis, the plasmid shows one DNA band, and the linear DNA shows two bands.
How does EcoRI differ from an exonuclease?
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ISC (CLASS XII) SPECIMEN QUESTION PAPER 2026
Short answer
Class 12 · Biology
Answer the following questions briefly.
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?
1 markShort answer
Class 12 · Biology
Answer the following questions briefly.
The diagram given below represents a specific stage of gestation period. Identify
the structure labelled - B.
1 markDiagram based
Class 12 · Biology
5] During a field excursion, a group of class XII students visited Kaziranga National Park and observed efforts to protect the Indian rhinoceros in its natural habitat. They also toured a botanical garden and a gene bank, where they saw endangered plant species and preserved seeds. Based on this context, answer the following questions:
Is Captive breeding an ex-situ or an in-situ strategy. Justify your answer with a
reason.
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ISC (CLASS XII) SPECIMEN QUESTION PAPER 2026
Short answer
Class 12 · Biology
2] Study the diagram given below and answer the following questions:
How are these DNA fragments visualised?
Diagram based
Class 12 · Biology
Answer the following questions briefly.
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.
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ISC (CLASS XII) SPECIMEN QUESTION PAPER 2026
(b) Even under similar environmental conditions, decomposition of the
exoskeleton of millipedes occurs more slowly than the leaves.
2 marksDiagram based
Class 12 · Biology
3] Study the pedigree chart given below showing the pattern of blood group inheritance in a family.
State the genotypes of the following:
(a) Parents
(b) The individual ‘X’ in the second generation
Short answer
Class 12 · Biology
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.
Short answer
Class 12 · Biology
Answer the following questions briefly.
Anita is suffering from dry and scaly lesions on various parts of the body. What is
the biological name of the causative fungus?
1 markShort answer
Class 12 · Biology
Study the diagram given below and answer the questions that follow.
(a) Name the molecule ‘X’ synthesised by ‘I’ gene. How does this molecule
get inactivated?
(b) Name the enzymes coded respectively by genes- z, y, and a.
(c) Which enzyme binds to the operator to initiate transcription?
Diagram based
Class 12 · Biology
3] A scientist is attempting to create a recombinant DNA molecule by combining a plasmid vector and a foreign DNA. A plasmid DNA and a linear DNA of the same size have a single site for the restriction enzyme EcoRI. When cut by the same RE and separated by gel electrophoresis, the plasmid shows one DNA band, and the linear DNA shows two bands.
What is the advantage of using agarose in gel electrophoresis?
Short answer
Class 12 · Biology
Answer the following questions briefly.
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.
1 markShort answer
Class 12 · Biology
2] 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. --------------------------------------------------------------------------------------------------------------------- ISC (CLASS XII) SPECIMEN QUESTION PAPER 2026 Visit CollegeDekho
Describe the trend observed between viral load and immune response following
initial infection.
Short answer
Class 12 · Biology
Answer the following questions briefly.
Observe the relation between the first two words and then complete the analogy.
Chikungunya: Aedes :: Malaria: ________.
1 markShort answer
Class 12 · Biology
3] A twenty-year old boy, Reshu has become addicted to alcohol.
Suggest any one measure by which addiction can be prevented.
Short answer
Class 12 · Biology
Answer the following questions briefly.
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.
1 markShort answer