SECOND YEAR HIGHER SECONDARY
EXAMINATION, 2025 SAY
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PART A: BOTANY
I. Answer any 3 questions from 1 to 5. Each carries 1 score. (3 x 1=3)
Choose the correct answer.
a) Stratification
b) Humus
c) Detritus
d) Standing crop
a) Stanley Cohen and Herbert Boyer
b) Watson and Crick
c) Verhulst-Pearl and Ramdeo Misra
d) Georgy Gause and P. Maheswary
Sea anemone and clown fish: Commensalism
Fig Flower and Wasp: ________
| a) | The stalk of ovule | Chalaza |
| b) | Protective envelopes of ovule | Integuments |
| c) | Small opening of ovule | Hilum |
| d) | Junction between ovule and funicle | Micropyle |
II. Answer any 9 questions from 6 to 16. Each carries 2 scores. (9 X 2 = 18)
• The first letter of the name comes from the genus and the next two letters come from the species of the prokaryotic cell from which they were isolated.
• The next letter is derived from the name of the strain.
• Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria.
a) Identify the type of age pyramid for human population.
b) Label age pyramid marked as A, B, C.
a) Stable population pyramid.
b) A: Post-reproductive, B: Reproductive, C: Pre-reproductive.
• Free-nuclear endosperm: The primary endosperm nucleus (PEN) undergoes successive nuclear divisions without wall formation, resulting in a large number of free nuclei.
• Cellular endosperm: Nuclear division is immediately followed by cell wall formation, making the endosperm cellular from the beginning.
a) Name the population interaction exit between copepodes and marine fishes.
b) Write the role of predation in an ecosystem.
a) Parasitism (Ectoparasitism).
b) Predators act as conduits for energy transfer across trophic levels and help keep prey populations under control.
• Cross-pollination (Xenogamy) and Geitonogamy are only possible in chasmogamous flowers.
• Reason: Chasmogamous flowers have exposed anthers and stigma, allowing pollen from other flowers to reach them. Cleistogamous flowers never open, so only self-pollination (Autogamy) is possible.
| Trophic levels | Number of individuals |
|---|---|
| TC (Tertiary Consumer) | 3 |
| SC (Secondary Consumer) | 354000 |
| PC (Primary Consumer) | 708000 |
| PP (Primary Producer) | 5842000 |
1. Birth rate: Refers to per capita births in a population over a given period.
2. Death rate: Refers to per capita deaths in a population over a given period.
(Other attributes include Sex ratio and Age distribution).
• Bt cotton contains inactive protoxins produced by Bacillus thuringiensis.
• When the insect ingests the plant, the protoxin is converted into an active form due to the alkaline pH of its gut.
• The activated toxin binds to the surface of midgut epithelial cells and creates pores, causing cell swelling and lysis, which eventually leads to the death of the insect.
a) What is productivity?
b) Name the types of productivity.
a) Productivity is the rate of biomass production per unit area over a time period.
b) Gross Primary Productivity (GPP) and Net Primary Productivity (NPP).
a) Name the two types of bioreactors labelled as a and b.
b) What are the optimal growth conditions provided by bioreactors to produce rDNA protein?
a) a: Simple stirred-tank bioreactor
b: Sparged stirred-tank bioreactor.
b) Bioreactors provide optimal growth conditions such as temperature, pH, substrate, salts, vitamins, and oxygen.
| Column A | Column B |
|---|---|
| a) Agrobacterium tumefaciens | i) Pest resistant plant |
| b) Bacillus thuringiensis (Bt) | ii) Genetically engineered insulin |
| c) Meloidegyne incognitia | iii) Gene transfer in plants |
| d) Escherichia coli | iv) Bt Cotton |
| Column A | Column B |
|---|---|
| a) Agrobacterium tumefaciens | iii) Gene transfer in plants |
| b) Bacillus thuringiensis (Bt) | iv) Bt Cotton |
| c) Meloidegyne incognitia | i) Pest resistant plant |
| d) Escherichia coli | ii) Genetically engineered insulin |
III. Answer any 3 questions from 17 to 20. Each carries 3 scores. (3 X 3 = 9)
a) Write one difference between dicot embryo and monocot embryo.
b) Mark the parts of dicot embryo labelled as A, B, C and D.
a) Dicot embryos have two cotyledons, while monocot embryos have only one cotyledons (scutellum).
b) A: Plumule, B: Cotyledons, C: Radicle, D: Root cap.
1. A large number of plants can be produced in a very short duration.
2. The plants produced are genetically identical to the original plant (somaclones).
3. Healthy plants can be recovered from diseased plants by using meristem culture.
a) Define decomposition.
b) Fill in the blanks with the steps of decomposition.
c) Write two climatic factors affecting decomposition.
a) Decomposition is the process by which complex organic matter is broken down into inorganic substances like carbon dioxide, water, and nutrients by decomposers.
b) A: Leaching, B: Humification.
c) Temperature and soil moisture.
a) Identify the plasmid.
b) Describe the role of tetR and ampR in rDNA technology.
c) State the function of rop.
a) pBR322.
b) They act as selectable markers which help in identifying and eliminating non-transformants and selectively permitting the growth of the transformants.
c) 'rop' codes for the proteins involved in the replication of the plasmid.
PART B: ZOOLOGY
I. Answer any 3 questions from 1 to 5. Each carries 1 score. (3 x 1 = 3)
a) AUG is a stop codon
b) UAG is a stop codon
c) AUG is a initiator codon
d) UAG is a initiator codon
(22A+XX, 22A+XO, 23A+XX, 22A+XXY)
(a) ET: Embryo Transfer.
(b) IUI: Intra-Uterine Insemination.
II. Answer any 9 questions from 6 to 16. Each carries 2 scores. (9 X 2 = 18)
a) Identify the figure.
b) How many histone molecules are present in the histone core?
c) Distinguish between Euchromatin and Heterochromatin.
a) Nucleosome.
b) 8 molecules (Histone octamer).
c) Euchromatin: Loosely packed, stains light, and is transcriptionally active. Heterochromatin: Densely packed, stains dark, and is transcriptionally inactive.
| A | B |
|---|---|
| Filariasis | Rhinovirus |
| Malaria | Trichophyton |
| Ringworm | Ascaris |
| Ascariasis | Wuchereria |
| Plasmodium |
| A | B |
|---|---|
| Filariasis | Wuchereria |
| Malaria | Plasmodium |
| Ringworm | Trichophyton |
| Ascariasis | Ascaris |
a) Mature ovum with follicle cells
b) Embryo with 8-16 cells
c) Perimetrium, Myometrium and Endometrium
d) Acrosome, middle piece, tail
a) Graafian follicle.
b) Morula.
c) Uterine wall (Uterus layers).
d) Sperm (Spermatozoon).
a) Give the scientific name of the organism used by Morgan for his experiments.
b) What was the reasons for selecting fruit fly as the experimental material?
a) Drosophila melanogaster.
b) They could be grown on simple synthetic medium, had a short life cycle (2 weeks), produced many offspring, and showed clear hereditary variations.
a) Identify and write the embryonic stage.
b) Name the parts labelled as A & B.
c) Write the function of 'B'.
a) Blastocyst.
b) A: Trophoblast, B: Inner cell mass.
c) The inner cell mass gets differentiated into the embryo.
Isolation of DNA → A → B → Transferring of separated DNA fragments to synthetic membrane → C → D
A: Digestion of DNA by restriction endonucleases.
B: Separation of DNA fragments by electrophoresis.
C: Hybridisation using labelled VNTR probe.
D: Detection of hybridised DNA fragments by autoradiography.
During Darwin's voyage to an island, he observed small black birds with variety of beaks as shown in the above figure.
a) Name the bird and the island.
b) What is the phenomenon depicted here?
a) Bird: Darwin's Finches. Island: Galapagos Islands.
b) Adaptive Radiation.
a) Name the principle.
b) Mention any two factors that affect this equilibrium.
a) Hardy-Weinberg Principle.
b) Gene migration, Genetic drift, Mutation, Genetic recombination, or Natural selection (Any two).
a) Identify the molecule.
b) Expand CMI.
c) Name the immunoglobulin produced during allergic condition.
a) Antibody (Immunoglobulin).
b) Cell-Mediated Immunity.
c) IgE.
a) What is STI?
b) Write any two measures that you can follow to prevent STI.
a) Sexually Transmitted Infections.
b) Avoid sex with unknown partners/multiple partners; Always use condoms during coitus.
| A | B |
|---|---|
| Trichoderma polysporum | Statin |
| Monascus purpureus | Ethanol |
| Saccharomyces cerevisiae | Lactic acid |
| Aspergillus niger | Cyclosporin A |
| Citric acid |
| A | B |
|---|---|
| Trichoderma polysporum | Cyclosporin A |
| Monascus purpureus | Statin |
| Saccharomyces cerevisiae | Ethanol |
| Aspergillus niger | Citric acid |
III. Answer any 3 questions from 17 to 20. Each carries 3 scores. (3 X 3 = 9)
a) The given surgical procedure is known as ________.
b) Which part is removed or tied up in this surgery?
c) Name the sterilisation method in females.
a) Vasectomy.
b) Vas deferens.
c) Tubectomy.
b) Name any two biodiversity hotspots in India.
a) A: Amazon rain forest/Tropical rain forests, B: Extinction of Steller's sea cow/Passenger pigeon, C: Alien species invasion, D: Co-extinctions.
b) Western Ghats and Himalayas.
a) Identify the process.
b) Name the enzyme involved in this process.
c) What is splicing?
a) Transcription (in Bacteria).
b) DNA-dependent RNA polymerase.
c) Splicing is the process in eukaryotes where introns are removed and exons are joined together.
a) Which polypeptide is abnormal?
b) Identify this autosome linked recessive disorder.
c) Give another example for autosomal linked recessive blood disease.
a) Polypeptide B.
b) Sickle-cell anaemia.
c) Thalassemia.