Brain Grain · braingrain.in
Botany — Practice Paper · Set 1
Class: 12Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.Groundnut is native of …………….. a) Philippines b) India c) North America d) Brazil[1]
2.The management of forest and afforestation on barren lands is ………………….. a) agroforestry b) Silvopasture c) Social forestry d) Afforestation[1]
3.The active principle trans-tetra hydro canabial is present in a) Opium b) Curcuma c) Marijuana d) Andrographis[1]
4.Virus free plants are developed from a) Organ culture b) Meristem culture c) Protoplast culture d) Cell suspension culture[1]
5.Column A Column B a. Domestication wheat 1. 1926 b. Blast resistant Rice 2. 1940 c. Insect Resistant Cotton 3. 1903 d. Waxy Corn 4. 1953[1]
6.Tobacco produces nicotine, coffee plants produce caffeine, cinchona plant produce quinine it is meant for……………. a. Predators b. Defence mechanism c. Proto cooperation d. Holoparasites[1]
7.Dwarfing gene of wheat is a) pal 1 b) Atomita 1 c) Norin 10 d) pelita 2[1]
8.Which of the given plant produces cardiac glycosides? a. Calotropis c. Nepenthes b. Acacia d. Utricularia[1]
9.pBR322 is most extensively studied a. Foreign gene b. r DNA c. done d. Plasmid DNA of Ecoli.[1]
10.The genotypic ratio of monohybrid cross is a. 3:1 b. 1:2:1 c. 3:1:1 d. 9:3:3:1[1]
11.……………. system is used in mining, Aviation, surveying agricultural and marie ecosystem. a) GIS b) GPS c) BIA d) EIA[1]
12.The position of organisms in food chain is refers to a. Ecosystem b. Trophic level c. Food chain d. Ten percent law[1]
13.For making GMO, the three basic steps that are required are a. Identification of DNA with desirable gene b. Introduction of identified DNA into the host c. Maintenance of introduced DNA in to the host and transfer of DNS to its progeny d. All the above[1]
14.In pea plants, yellow seeds are dominant to green. If a heterozygous yellow seed plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants would you expect in FI generation? a) 9:1 b) 1:3 c) 3:1 d) 50:50[1]
15.Zymology is the study of a. Fermentation & its practical use b. Name of Bioreactors c. Upstream pro^ss d. Downstream process[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.Define pedology[2]
17.How is Sorghum useful?[2]
18.What is Bio-pesticides with example[2]
19.What is ecological pyramid ?[2]
20.Based on the varieties of benefits obtained from ecosystem what are the various types ecosystem services ?[2]
21.What is the endothelium?[2]
22.What does the word’perfume’mean?[2]
23.Name the major tribal communities in Tamil Nadu known for their medicinal knowledge?[2]
24.Choose the incorrect pair a.PBR 322 Ecoli cloning vector b.EcoRl — cIal, Hind 1H Restriction Enzyme c.ROP Protein involved in the replication of the plasmid d.PCR Technique in which multiple copies of the gene (or DNA) of interest is synthesized, invitro[2]
25.Write about Endosperm?[2]
26.What is cybrid?[2]
27.Write the benefits of environmental impact assessment.[2]
28.What are the various altitudinal zonation of vegetation?[2]
29.Column A Column B a. Green Revolution I. Muller and stadler b. Mutation Breeding II. G.H. Shull c. Heterosis III. William S. Gaud d. Director of IARI IV. Dr.B.P. Pal A) a – ii, b – iii, c-iv, d-i B) a – iii, b-ii, c-i, d-iv c) a – iii, b – i, c-ii, d-iv D) a – i, b-iv c-iii, d-ii[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.How does the monosporic embryosac develop?[5]
31.Write about the significance of plant succession.[5]
32.Differentiate continuous variation with discontinuous variation.[5]
33.How are microbial innoculants used to increase the soil fertility?[5]
34.A detached leaf of Bryophyllum produces new plants. How?[5]
35.How does the laws of thermodynamics explain the storage and loss of energy in an ecosystem ? (or) Write about laws of thermodynamics in an ecosystem.[5]
36.‘Pollination in Gymnosperms is different from Angiosperms’ – Give reasons.[5]
37.a. DNA probes are used in the identification of viruses and other pathogen. b. RNA probes are used in the identification of bacteria as pathogens. c. Northern Blotting can also be used in the «identification of pathogenecity of viruses. d. Southern Blotting help as a tool to identify virus and other pathogens.[5]
38.What is Bio-Diversity conservation movement.[5]
39.With regard to transgenic organism & the processes a. Biopharrning genetically engineered pharmaceuticals substances b. Mycoremediation use of bacteria to bring about environmental remediation d. Bioaugmentation use of selected microbes to speed up degradation process d. Bioleaching use of microbes to recover metal pollutants from contaminated place[5]
🔑 Show Answer Key — Set 1
- 1. d) Brazil
- 2. c) Social forestry
- 3. c) Marijuana
- 4. b) Meristem culture
- 5. b) Blast resistant Rice -1940
- 6. b. Defence mechanism
- 7. c) Norin 10
- 8. a. Calotropis
- 9. d) Plasmid DNA of Ecoli
- 10. b) 1:2:1
- 11. b) GPS
- 12. b. Trophic level
- 13. d) All the above
- 14. d) 50: 50
- 15. a) Fermentation & its practical use
- 16. Pedology is the scientific study of soils, including their formation, composition, structure, properties, classification, and distribution. It encompasses the examination of soil profiles, weathering processes, soil horizons, and the various factors that influence soil development such as climate, parent material, topography, organisms, and time. Pedology is essential for understanding soil fertility, land use planning, agriculture, and environmental management.
- 17. It is used to feed poultry, birds, pigs, cattle. Source of fermented alcoholic beverage.
- 18. Bio-pesticides are biologically based agents or preparations used for the control of plant pests and diseases. They are derived from living organisms or their byproducts and are environmentally friendly alternatives to synthetic chemical pesticides. A common example of bio-pesticide is Trichoderma, a fungus that acts as a biocontrol agent against various plant pathogens and pests. Other examples include Bacillus thuringiensis (Bt), which produces toxins lethal to insect larvae, and various entomopathogenic fungi and bacteria. Bio-pesticides are safer for the environment, non-toxic to humans and beneficial organisms, and help maintain ecological balance in agricultural systems.
- 19. An ecological pyramid is a graphical representation that illustrates the relationship between different trophic levels in an ecosystem. It depicts the structure and function of the ecosystem by showing the biomass, number of individuals, or energy content at each successive trophic level, starting from producers at the base and moving up through primary, secondary, and tertiary consumers.
- 20. The varieties of benefits obtained from ecosystems are generally categorized into four main types of ecosystem services. Provisioning services include the direct products obtained from ecosystems such as food, fresh water, fuel, fiber, and medicinal plants. Regulating services are the benefits obtained from the regulation of ecosystem processes, including air quality maintenance, climate regulation, water purification, pollination, and pest control. Supporting services are the natural processes that maintain all other ecosystem services, such as nutrient cycling, soil formation, and primary production. Cultural services are the non-material benefits that people obtain from ecosystems, inc…
- 21. In Asteraceae species, the inner layer of the integument becomes specialized to nourish the developing embryo sac and is called the integumentary tapetum or endothelium. This specialized layer plays a crucial role in providing nutrients and other essential substances required for the proper development and maturation of the female gametophyte, ensuring successful reproduction in these flowering plants.
- 22. ‘Perfume’ is a word derived from Latin. Per (through) and fumus (to smoke) means through smoke. Age old tradition of burning scented woods at religious ceremonies.
- 23. The major tribal communities in Tamil Nadu known for their extensive medicinal knowledge are the Irulas, Malayalis, Kurumbas, Paliyans, and Kaanis. These indigenous communities have preserved traditional knowledge of medicinal plants and their therapeutic applications over generations. Their understanding of local flora and its medicinal properties represents valuable ethnobotanical knowledge that has been developed through long-term interaction with the natural environment and traditional healing practices.
- 24. The incorrect pair is c) ROP – Protein involved in the replication of the plasmid. ROP (Repressor of Primer) is actually a protein that regulates and inhibits the replication of the plasmid rather than being involved in promoting its replication. The other pairs are correct: PBR 322 is indeed a cloning vector used in E. coli, EcoRI, ClaI, and HindIII are all restriction enzymes, and PCR is the technique in which multiple copies of a gene or DNA of interest are synthesized in vitro.
- 25. The endosperm is a nutritive tissue that develops from the fusion of the polar nuclei with one sperm nucleus during double fertilization in flowering plants. After the zygote divides to form the embryo, the endosperm continues to develop and accumulate nutrients such as starch, proteins, and oils. This tissue serves as the primary source of nutrition for the developing embryo during seed development and germination. The endosperm is also a regulatory structure that controls the growth and development of the embryo through the production of various signaling molecules and hormones. In many seeds, the endosperm remains as a storage tissue that nourishes the seedling during the early stages…
- 26. A cybrid is a fusion product obtained when protoplasts from two different plant cells, where at least one protoplast lacks a nucleus, are fused together. The term cybrid is derived from cytoplasmic hybrid, indicating that the resulting cell contains cytoplasm from both parent cells but the nucleus typically comes from only one parent. This technique is used to combine desirable cytoplasmic traits from different species while maintaining nuclear genetic material from a selected parent, creating novel combinations that cannot be achieved through conventional breeding methods.
- 27. A healthier environment. Maintenance of biodiversity Decrased resource usage. Reduction in gas emission and environment damage.
- 28. The various altitudinal zonation of vegetation from lower to higher elevations includes tropical rainforests at lower altitudes, grasslands or deserts at intermediate elevations, deciduous forests at moderate elevations, coniferous forests at higher elevations, and tundra and snow at the highest elevations. This pattern of vegetation zonation with increasing altitude is similar to latitudinal zonation because temperature decreases with altitude just as it decreases with latitude. Each altitudinal zone supports vegetation adapted to the specific temperature, moisture, and atmospheric conditions at that elevation.
- 29. c) a-iii, b-i, c-ii, d-iv. The correct matching is: Green Revolution – William S. Gaud (a-iii), Mutation Breeding – Muller and Stadler (b-i), Heterosis – G.H. Shull (c-ii), and Director of IARI – Dr. B.P. Pal (d-iv). These represent the key scientists and concepts associated with major developments in plant breeding and agricultural improvement.
- 30. Functional megaspore is the first cell of embryosac or female gametophyte. Megaspore elongates along micropylar – chalaza! axis. Nucleus undergoes mitosis without wall formation. A central vacuole expands and pushed the nuclei towards the opposite poles. Each nucleus divide mitotically twice. Thus 4 nuclei are formed at each pole. Eight nuclei are in common cytoplasm. Of the 4 nuclei at micropylar end, 3 nuclei form 3 antipodal cells. Fourth one is the lower polar nucleus. Two polar nuclei fuse into secondary nucleus. Thus 7 celled, 8 nucleated embrovsac is formed.
- 31. Significance of Plant Succession: * Succession is a dynamic process. Hence an ecologist can access and study the serai stages of a plant community found in a particular area. * The knowledge of ecological succession helps to understand the controlled growth of one or more species in a forest. * Utilizing the knowledge of succession, even dams can be protected by preventing siltation * It gives information about the techniques to be used during reforestation and afforestation. * It helps in the maintenance of pastures. * Plant succession helps to maintain species diversity in an ecosystem. * Patterns of diversity during succession are influenced by resource availability and disturbance by…
- 32. Variation is the difference between individual with in a species. This can be caused by inherited or environmental factors. It can be continuous and discontinuous. Height, and weight of the human being are best examples of continuous variation. Human blood group, gender identity and eye colour are best example of discontinuous variation Continuous Variation Discontinuous Variation Variation are fluctuate or mean mean or average is absent Direction is predictable unpredictable already exists in the population variation occur previously It is due to the chance of segregation of chromosomes during gamete formation & crossing over & chance pairing during fertilisation Produced by changes in g…
- 33. Biofertilizers or microbial inoculants are preparations containing living cells or latent cells of efficient strains of microorganisms that enhance crop plant nutrient uptake through their interactions in the rhizosphere when applied through seed or soil. These microbial inoculants are efficient in fixing atmospheric nitrogen, solubilizing insoluble phosphate compounds, and decomposing cellulose in the soil. They are specifically designed to improve soil fertility, promote plant growth, and increase the number and biological activity of beneficial microorganisms in the soil ecosystem. Common biofertilizers include nitrogen-fixing bacteria like Azotobacter and Rhizobium, phosphate-solubili…
- 34. Bryophyllum undergoes vegetative reproduction in the leaf. The succulent leaf is notched in its margin. Adventitious buds develop at these notches. They are called epiphyllous buds. These buds develop a root system. When the leaf decays, they become independent plants.
- 35. Laws of thermodynamics: The storage and loss of energy in an ecosystem is based on two basic laws of thermodynamics. i) First law of thermodynamics * It states that energy can be transmitted from one system to another in various forms. Energy cannot be destroyed or created. * As a result, the quantity of energy present in the universe is constant. * Example: In photosynthesis, the product of starch (chemical energy) is formed by the combination of reactants (chlorophyll, H 2 O, CO 2 ). ‘ “ Starch is acquired from the external sources (light energy) and so there is no gain or loss in total energy. Here light energy is converted into chemical energy. * Light energyv → Chemical energy ii) Se…
- 36. Pollination in gymnosperms differs fundamentally from that in angiosperms in terms of the position of ovules and the mechanism of pollen deposition. In gymnosperms, the ovules are exposed and unenclosed, and pollen grains are deposited directly on the ovule surface. This is referred to as direct pollination. In contrast, angiosperms have enclosed ovules contained within the ovary, and pollination is an indirect process wherein pollen grains are first deposited on the stigma of the pistil or carpel. From the stigma, the pollen tube must grow through the style to reach the ovule for fertilization. This fundamental difference reflects the evolutionary advancement of angiosperms, where the ca…
- 37. b) RNA probes are used in the identification of bacteria as pathogens IV. Fill in the blanks Answer 1. The method that involved the growth of tissues & cells in a suitable new medium and away from the parent plant is known as……………………. Tissue culture 2. The range of insects killed by Bt. Toxins are……………………. Lepitopteron 3. The genes that code for Bt toxins are commercially called……………………. Cry genes 4. The first company to produce insulin by rDNA technology is……………………. Eli Lilly 5. The Indian scientist who was the innovator of ELISA in India is……………………. Usha M.Joshi 6. PCR is usually used to detect the……………………. in a suspected …………………….patient. HIV & AIDS 7. Are present in increased quantiti…
- 38. Conservation movement * A community level participation can help in preservation and conservation of our environement. * Our environment is a common treasure for all the living organisms on earth. Every individual should be aware of this and participate actively in the programs meant for the conservation of the local environment. * Indian histroy has witnessed many people movements for the protection of environment. Chipko Movement * The tribal women of Himalayas protested against the exploitation of forests in 1972. Later on it transformed into Chipkon Movement by Sundarlal Bahuguna in, Mandle village of Chamoli district in 1974. * People protested by hugging trees together which were fe…
- 39. Biotechnology offers diverse applications for environmental remediation and resource recovery. Biopharming involves the cultivation of genetically engineered plants or animals to produce valuable pharmaceutical substances, such as vaccines or antibodies, in a cost-effective manner. Mycoremediation utilizes fungi to break down or absorb environmental pollutants, including hydrocarbons and heavy metals, thereby cleaning contaminated sites. Bioaugmentation enhances the natural degradation processes in the environment by introducing or stimulating specific microbial populations that are capable of breaking down persistent waste products more rapidly. Bioleaching employs microorganisms, partic…
Brain Grain · braingrain.in
Botany — Practice Paper · Set 2
Class: 12Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.Match A. Rice 1. East Africa B. Wheat 2. Africa C. Ragi 3. Crescent Region D. Sorghum 4. South East Asia a) A-4, B-3, C-l, D-2 b) A-l, B-2, C-3, D-4 c) A-4, B-3, C-2, D-l d) A-2, B-l, C-4, D-3[1]
2.Pure tall plants are crossed with the pure dwarf plants. In the FI generation, all plants were tall. These tall plants of the F1 generation were selfed and the ratio of tall to dwarf plants obtained was 3: 1. This is called a) Dominance b) Inheritance c) Codominance d) Heredity[1]
3.Rhizome is not in a) Musa paradisiaca b) Zingifer officinale. c) Curcuma longa d) Colocasia[1]
4.The study of Drugs or medicines used in medical treatment is known as. a. Pharmaceuticals b. Biomedical Engineering c. Chemical Engineering d. Tissue Engineering[1]
5.Consider the following statements and choose the right option. i) Cereals are members of grass family ii) Most of the food grains come from monocotyledon a) (i) is correct and (ii) is wrong b) Both (i) and (ii) are correct c) (i) is wrong and (ii) is correct d) Both (i) and (ii) are wrong[1]
6.First cell of male gametophyte in angiosperm is a) Microspore b) megaspore c) Nucleus d) Primary Endosperm Nucleus[1]
7.Indigenous to western ghats of India a) Black pepper b) Cardamom c) Turmeric d) Red pepper[1]
8.Which one of the following palindromic base sequence in DNA can be easily cut about the middle by some particular restriction enzymes? a) 5’ CGTTCG 3′ 3′ ATCGTA 5! b) 5’ GATATG3′ 3′ CTACTA 5’ c) 5′ GAAHC 3′ 3′ CTTAAG 5′ d) 5′ CACGTA 3′ 3′ CTCAGT 5′[1]
9.Germ plasm conservation does not include a) DNA bank b) Seed bank c) SWISS bank d) pollen bank[1]
10.Ecosystem consists of a. decomposers b. producers c. consumers d. all of the above[1]
11.Transmitting tissue is found in a) Micropylar region of ovule b) Pollen tube wall c) Stylar region of gynoecium d) Integument[1]
12.Which of the following would most likely help to slow down the greenhouse effect. a) Converting tropical forests in to grazing land for cattle. b) Ensuring that all excess paper packing is buried to ashes. c) Redesigning landfill dumps to allow methane to be collected. a) Promoting the use of private rather than puplic transport.[1]
13.Find the correct statement a) Carrot grass causes allergy b) Bee pollen is an artificial substance. c) Palynology is the study of honey pollen. d) Mellitopalynology is the study of pollen grain.[1]
14.NPP of whole biosphere is estimated to be …………. about billion tons dry weight/year a. 140 b. 170 c. 150 d.160[1]
15.Choose the odd man out with regard to protoplasmic fusion a) somatic hybridization b) Protoplasmic fusion c) Embryoids d) Polyethylene Glycol[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.What is the role of an Entrepreneur?[2]
17.Define phyllode?[2]
18.What is continuous variation with examples?[2]
19.What are the tools for genetic engineering?[2]
20.Column A Column B a. Mutational Breeding 1. Triticale b. Polyploid Breeding 2. Atomita -2 c. M.S. Swaminathan 3. TN 1 – hybrid rice d. Jaya and Ratna 4. Semi dwarf wheat[2]
21.What is Agricultural drone?[2]
22.Comment on the sculpturing pattern of pollengrains?[2]
23.Name the process which is essential for recycling and balancing the nutrient in an ecosystem?[2]
24.Give the uses of purified dissolving pulp?[2]
25.Column A Column B a. Atomic Garden I. Dwarfing Genes b. Protein Enriched II. Caesium 137 c. Vitamin C Entiched III. French Peas d. Norin 10 IV. Bitter Gourd A) a – i, b – ii, c – iv, d – iii B) a – ii, b – iii, c – iv, d – i c) a – iii, b – iv, c – i, d – iii D) a – iv, b – i, c – iii, d – ii[2]
26.Why do different types of vegetation occur from equator to poles (or) latitudes?[2]
27.In-situ, Ex-situ, National parks, Biosphere Reserves, Remote seming. a) Remote seming, while other are related to biodiversity conservation. b) National parks, while others are man made project. c) Biosphere reserves, detecting and monitoring the physical characteristic of an area. d) None of the above.[2]
28.Seeds of maple gyrocarpus, dipterocarpus and terminalia exhibit which type of adaptations for dispersal of fruits and seeds?[2]
29.Why does the zygote divide only after the division of the Primary endosperm cell?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.Write a short note on Punnett square or checkerboard?[5]
31.Biosphere Reserves, National parks and wildlife sanctuaries are community protected Bio-diversity conservation.[5]
32.Organic farming is considered as the movement towards the philosophy of Back to Nature. Explain[5]
33.Differentiate between upstream & downstream process[5]
34.Are there any possibilities to transfer a suitable desirable gene to host plant without vector? Justify your answer.[5]
35.Eichhornia crassipes is an invasive weed native to south America. It affects the growth of A and finally leads to B. A B a) Phytoplankton 1) eutrophication b) Prosopis 2) oxygen content c) Topography 3) geology d) Plants 4) environmental issues[5]
36.What are the different types of hybridization?[5]
37.Give a concise account on steps involved in the fertilization of an angiosperm plant.[5]
38.Discuss which wood is better for making furniture.[5]
39.Give a detailed account on the ‘National Fruit of India’?[5]
🔑 Show Answer Key — Set 2
- 1. a) A-4, B-3, C-l, D-2
- 2. a) Dominance
- 3. d) Colocasia
- 4. a) Pharmaceuticals
- 5. b) Both (i) and (ii) are correct
- 6. a) Microspore
- 7. a) Black pepper
- 8. c) 5′ GAAHC 3′ 3′ CTTAAG 5′
- 9. c) SWISS bank
- 10. d. all of the above
- 11. c) Stylar region of gynoecium
- 12. c) Redesigning landfill dumps to allow methane to be collected. This option would most likely help to slow down the greenhouse effect because methane is a potent greenhouse gas that contributes significantly to global warming. By collecting methane from landfills before it is released into the atmosphere, the amount of this greenhouse gas entering the environment is reduced, thereby decreasing its contribution to the greenhouse effect. Converting tropical forests into grazing land for cattle (option a) would worsen the greenhouse effect by removing carbon-sequestering trees and increasing methane emissions from cattle. Burying excess paper packing to ashes (option b) does not address gree…
- 13. a) Carrot grass causes allergy
- 14. b. 170
- 15. c) Embryoids
- 16. One who works to create a product or service that people will buy He builds an organization to support the sales.
- 17. A phyllode is a modified petiole that has become flattened, expanded, and fleshy, taking on a leaf-like appearance and function. In plants with phyllodes, the actual leaf blade may be reduced or absent, and the petiole assumes the role of photosynthesis and other functions normally performed by leaves. This modification represents an adaptation in certain plants to reduce water loss while maintaining photosynthetic capacity. An example is Acacia melanoxylon, where the petioles are modified into phyllodes that serve as the primary photosynthetic organs.
- 18. Continuous variation refers to variation in a characteristic in which individuals in a population show a range of traits with small, gradual differences between them, forming a continuous spectrum rather than distinct categories. This type of variation is typically controlled by multiple genes (polygenic inheritance) and is significantly influenced by environmental factors. Examples include human height, skin color, eye color, and weight in humans, as well as plant height and seed size in plants. In continuous variation, individuals display all intermediate phenotypes between the two extremes, and the variation follows a normal distribution curve when plotted graphically.
- 19. Enzymes (1) restriction endonuclease (2) DNA ligase Vectors Host organisms
- 20. The correct matching of breeding methods, varieties, and scientists is: Mutational Breeding is exemplified by the development of semi-dwarf wheat varieties (4) which often involved induced mutations. Polyploid Breeding is a key technique used in developing varieties like Triticale (1). M.S. Swaminathan is a renowned Indian plant breeder who made significant contributions, including work on semi-dwarf varieties and hybrid rice (3. TN 1 – hybrid rice is an example, though Jaya and Ratna (d) are also semi-dwarf rice varieties he worked with). Jaya and Ratna (d) are semi-dwarf rice varieties. Atomita-2 (b) is a variety of durum wheat. Therefore, the most fitting match is c) M.S. Swaminathan –…
- 21. Agricultural drone is an unmanned aerial vehicle to help increased crop production and monitor crop, growth. Farmers can see their fields from the sky.
- 22. The exine is sculptured as rod, groove, wart, punctuation etc. This pattern is used in plant identification and classification.
- 23. Decomposition is the essential process for recycling and balancing nutrients in an ecosystem. It is a process in which detritus is broken down into simple organic matter by decomposers such as bacteria and fungi. Through decomposition, complex organic compounds are converted into simpler inorganic nutrients that can be reabsorbed by plants and other organisms, thereby completing nutrient cycles and maintaining the balance of essential elements like nitrogen, phosphorus, and carbon within the ecosystem.
- 24. Purified dissolving pulp has several important industrial applications. It is used in the manufacture of rayon and artificial silk through the viscose process, which is the most common method of rayon production. Dissolving pulp is also employed in the production of various fabrics and textile materials. Additionally, it is used to manufacture transparent films such as cellophane and cellulose acetate films, which have applications in packaging and other industries. Purified dissolving pulp is further utilized in the production of plastics and other cellulose-based materials.
- 25. The correct matching of terms related to plant breeding and specific examples is: Atomic Garden is a facility for studying the effects of radiation, often involving sources like Caesium 137 (b-ii). Protein Enriched varieties are exemplified by French Peas (c-iii), known for higher protein content. Vitamin C Enriched varieties include Bitter Gourd (d-iv), which is rich in Vitamin C. Dwarfing Genes (a-i) are crucial for developing semi-dwarf varieties like Norin 10 (a-i). Therefore, the correct option is B) a – ii, b – iii, c – iv, d – i. Let's re-evaluate based on the provided answer B) a – ii, b – iii, c – iv, d – i. This implies: a. Atomic Garden - Dwarfing Genes (Incorrect). b. Protein…
- 26. Latitudes represent distance from the equator. Temperature values are maximum at the equator and decrease gradually towards poles. So different types of vegetation occur in latitude.
- 27. The correct answer is a) Remote sensing, while others are related to biodiversity conservation. Remote sensing is a technique that uses satellite imagery and aerial photography to detect and monitor physical characteristics of an area from a distance. In-situ conservation, ex-situ conservation, national parks, and biosphere reserves are all direct methods and strategies employed for the conservation and protection of biodiversity. Remote sensing serves as a tool to support these conservation efforts by providing data and monitoring capabilities, but it is not itself a biodiversity conservation method like the others listed.
- 28. Seeds or whole fruits of maple, gyrocarpus, dipterocarpus, and terminalia exhibit anemochorous adaptations for dispersal by wind. The seeds or fruits are flattened and modified to form wing-like structures or appendages that increase their surface area and reduce their density. These winged structures allow the seeds to be carried long distances by air currents, ensuring wide dispersal and colonization of new habitats. The aerodynamic design of these winged fruits enables them to glide through the air and land at considerable distances from the parent plant.
- 29. The primary endosperm nucleus divides prior to zygotic division and forms the endosperm tissue. Endosperm acts as a nutritive tissue that provides essential nutrients and nourishment to the developing embryo. Since the embryo requires a ready supply of nutrients for its growth and development, the endosperm must be formed first to support the embryo's development. Therefore, the zygote divides only after the primary endosperm nucleus has divided and established the endosperm, ensuring that nutritive support is available for the developing embryo from the early stages of its growth.
- 30. A Punnett square, also called a checkerboard, is a graphical tool used to predict the outcomes of genetic crosses and determine the probability of offspring genotypes and phenotypes. In this matrix, the male and female gametes and their frequencies are arranged along the horizontal and vertical edges, while the cells within the square show all possible combinations of alleles that can result from fertilization. The Punnett square is particularly useful for visualizing monohybrid and dihybrid crosses, allowing geneticists to calculate the expected ratios of dominant and recessive traits in the offspring. By systematically filling in each cell with the combined alleles from the parent gamet…
- 31. Biosphere reserves, national parks, and wildlife sanctuaries represent different levels and approaches to biodiversity conservation, though they are all government-protected areas. Biosphere reserves are large designated areas that combine strict nature reserves with buffer zones and transition zones, allowing both conservation and sustainable use of resources while supporting research and education. National parks are protected areas established to preserve ecosystems, wildlife, and natural features of scientific and recreational importance, with restricted human activities. Wildlife sanctuaries are areas designated primarily for the protection and conservation of specific wildlife speci…
- 32. Organic farming is an alternative agricultural system in which plants / crops are cultivated in natural ways by using biological inputs to maintain soil fertility and ecological balance thereby minimizing pollution and wastage Indians were organic farmers by default until the green revolution came in to practice. Use of bio-fertilizers is one of the important components of integrated organic farm management, as they are cost effective and renewable source of plant nutrients to supplement the chemical fertilizers for sustainable agriculture. Several microorganisms and their association with crop plants are being exploited in the production of bio-fertilizers. Organic farming is thus consid…
- 33. Upstream and downstream processes are two distinct phases in industrial biotechnology operations, particularly in fermentation. The upstream process encompasses all activities that occur before the main bioprocess, such as fermentation, begins. This phase is critical for ensuring optimal conditions for microbial growth and product formation. It includes the meticulous sterilization of the bioreactor to eliminate any contaminating microorganisms, the preparation and sterilization of the culture medium containing all necessary nutrients, and the cultivation of a suitable inoculum of the desired microorganism. The downstream process, on the other hand, follows the fermentation stage and invo…
- 34. Yes, it is possible to transfer a suitable desired gene to a host plant using certain chemicals, microinjection method, electroporation or by biolistics. a. Chemical mediated gene transfer: Chemicals Poly Ethylene Glycol (PEG) & Dextran sulphate – induce DNA uptake into plant protoplasts. b. Microinjection: With a fine-tipped glass needle, DNA is directly injected into the nucleus. The protoplasts are immobilized on solid support (agarose on a microscopic slide) c. Electroporation method of gene transferJjjJU Protoplasts, cells or tissues subjected to a pulse of high voltage electric power to make transient pores in the plasma membrane, through which uptake of foreign DNA occurs. d. Lipos…
- 35. a) Phytoplankton – 1) eutrophication XI. Fill in the blanks Answers 1. ………………. is another long term method to store carbon. Biochar 2. …………………. is the total amount of green house gases produced by human activated. Carbon foot print 3. Eating indigenous fruits and products are reduce ……………… Carbon foot print 4. The forest, soil, ocean are …………………. and landfills are ………….. sinks. Natural, artificia Dobson unit 5. The thickness of the ozone column of air is measured in terms of ……………… Chloro fluro carban 6. …………………. is the anthropogenic greenhouse gas. Tank Foreshore 7. _____ plantations have been a major source of fire wood in Tamilnadu. Plantations 8. World ozone Day is celebrated on ………………
- 36. Types of hybridization: (i) Intravarietal hybridization: The cross between the plants of same variety. such crosses are useful only in the self. pollinated crops. (ii) Intervarietal hybridization: The cross between the plants belonging to two different varieties of the same species and is also known as intraspecific hybridization. (iii) Interspecific hybridization: The cross between the plants belonging to different species belonging to the same genus is also called intragenic hybridization. Example: Gossypium hirsutum Gossypium arboreum (v) Intergeneric hybridization: * The crosses are made between the plants belonging to two different genera. * The disadvantages are hybrid sterility tim…
- 37. Steps in the fertilization of Angiosperms 1. Germination of pollen to form pollen tube in the stigma. * Pollens fall on receptive stigma. * Compatible pollen germinates to form a tube. * This is helped by stigmatic fluid in wet stigma and pellicle in dry stigma. * Compatibility is decided by recognition, rejection protein reaction, between pollen and stigma surface. * Pollen undergoes hydration. Pollen wall proteins cire released. * The entire content moves into pollen tube. * Growth is at the cytoplasmic contents at the tip. * The remaining part of pollen tube is occupied by a vacuole. * It is cut off from tip by callose plug. * The hemispherical, transparent pollen tip of pollen tube is…
- 38. Teak wood is considered the ideal type of wood for making household furniture due to its superior qualities and durability. Teak wood is highly durable and exhibits great resistance against the attack of termites and fungi, which are common causes of wood deterioration. Moreover, teak wood does not split or crack easily, even under varying humidity and temperature conditions, making it stable and long-lasting. Additionally, teak wood is carpenter-friendly, meaning it is easy to work with during the manufacturing and finishing processes. These combined properties make teak wood the preferred choice for furniture that requires longevity, aesthetic appeal, and resistance to environmental dam…
- 39. Mango (Mangifera indica) belongs to the family Anacardiaceae Origin and area of cultivation. * Native of southern Asia, Burma and Eastern India. * Andhra, Bihar, Gujarat and Karnataka are mango producing states. * Salem, Krishnagiri, Dharmapuri are mango producing districts of Tamil Nadu. * Major cultivars of Mango are Alphonsa, Banganapalli, Neelam and Malgova. Uses: * Major Indian table fruit. * Rich in beta carotenes. * Used as dessert, canned, dried, preserves in Indian cuisine. * Unripe mangoes are used in chutney, pickle, side dishes, eaten raw with salt, chilli. * Pulp is made as jelly * Aerated, non aerated soft drinks are prepared.
Brain Grain · braingrain.in
Botany — Practice Paper · Set 3
Class: 12Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.The term ‘ecosystem’ was proposed by……………..in the year 1935. a. A.G. Hoxley b. A.G.Tansley c. Odum d. Lindeman[1]
2.An allele which has the potential to cause the death of an organism is called a. Genetic interaction b. lethal alleles/lethal gene c. Atavism d. Autism[1]
3.The study of heredity behaviour of several genes by Gregor Mendel. a. Molecular genetics b. Population genetics c. Quantitative genetics d. Transmission genetics[1]
4.With regard to SCP – Choose the odd man out. a. Chlorella b. Spirulina c. Chlamydomonas d. Bacillus thuringiensis[1]
5.Solidifying agent used in plant tissue culture is a) Nicotinic acid b) Cobaltous chloride c) EDTA d) Agar[1]
6.Which one of the following is incorrect regarding chromosomal behaviour during cell division? a) The alleles of a genotype are found in the some locus of a homologous chromosome b) In the S phase of meiotic interphase each chromosome replicates forming two copies of each allele, one on each chromatid. c) The Homologus chromosomes segregate in metaphase I, thereby separating two different alleles. d) In anaphase II of meiosis separation of sister chromatid of homologous chromosomes takes place.[1]
7.Not in exine of pollen grain a) Cellulose b) Sporopollenin c) Pollenkitt d) Callose[1]
8.Somatic embryogenes is not applied in a) Oryza sativa b) Hordeum vulgare c) Ficus bengaliensis d) Avena sativa[1]
9.Oxalis shows ………………… a) Cleistogamy b) Homogamy c) Incomplete dichogamy d) Geitonogamy[1]
10.This enzyme is purified from bacteria and calf intestine is a. DNAligase b. Alkaline Phosphatase c. Exo nuclease d. Endo nuclease[1]
11.Which of the following pair is not correct a. KK=dominant b. hybrid = heterogeneous c. heterozygous = Kk d. homozygous = Rr[1]
12.The recessive character will express in a. F 1 b. F 2 c. both a & b d. F 3 only[1]
13.Which one of the following is a correct set? a) Vincristine Cinchona officinalis Anti carcinogen b) Capsacin catharanthus roseus – Antimalarial c) Digoxin Digitalis purpuria Cardiac tonic d) Codeine Capsicum annum Analgesic[1]
14.The group of degradable biopolymers are a. CrylAc and DMH-11 b. PHAsandPHB c. GFPandPGA d. DMH and HT[1]
15.Which one of the following is not a correct pair regarding genes of pea plant, a. Seed shape – Chromosome number 6 b. Pod colour – Chromosome number 5 c. Flower position – Chromosome number 4 d. Seed colour – Chromosome number 1[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.What is Biosafety?[2]
17.What are the plant breeding tools used to improve the crop varieties?[2]
18.Define Zoophily?[2]
19.What is Genome project?[2]
20.Why the pyramids of energy is always upright?[2]
21.What are the minor nutrients added in MS medium?[2]
22.What do you mean standing quality (or) Standing state of abiotic components ?[2]
23.Enlist the disadvantages of cross pollination?[2]
24.What are genes ?[2]
25.Totipotency refers to. a) capacity to generate genetically identical plants. b) capacity to generate a whole plant from any plant cell/explant. c) capacity to generate hybrid protoplasts. d) recovery of healthy plants from diseased plants.[2]
26.Write a note on co-dominance ?[2]
27.What is breathing roots? Give an example.[2]
28.What are Fossil Genes?[2]
29.What is biotope and ecotope?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.Differentiate between Euploidy & Aneuploidy[5]
31.What are the future prospects of Biotechnology?[5]
32.Why dust and humid night than dust free nights? (or) Does clouds and dust particles cause global warming?[5]
33.Why pyramids of biomass in pond ecosystem is always inverted in shape?[5]
34.Explain epihy drophily with an example?[5]
35.Highlight the milestones from the history of plant embryology.[5]
36.Ovules are of many types based on the orientation, form, position of micropyle with respect to funicle, chalaza – discuss?[5]
37.What is the Albedo effect and write their effects?[5]
38.What are the importance of studying food web ? (or) What are significant of food web? Is there any significance in maintaining food web?[5]
39.Name the chemicals used in gene transfer.[5]
🔑 Show Answer Key — Set 3
- 1. b. A.G. Tansley
- 2. b) lethal alleles/lethal genes
- 3. d) Transmission genetics
- 4. d) Bacillus thuringiensis
- 5. d) Agar
- 6. c) The Homologous chromosomes segregate in metaphase I, thereby separating two different alleles. This statement is incorrect because homologous chromosomes do not segregate during metaphase I. During metaphase I, homologous chromosomes are aligned at the metaphase plate, and it is during anaphase I that homologous chromosomes separate and move to opposite poles of the cell. The separation of homologous chromosomes during anaphase I is what actually separates the different alleles carried on these chromosomes. The other statements are all correct: alleles of a genotype are found at the same locus on homologous chromosomes, chromosomes replicate during S phase forming two copies of each al…
- 7. d) Callose
- 8. c) Ficus bengaliensis
- 9. a) Cleistogamy
- 10. b) Alkaline Phosphatase
- 11. a) KK=dominat
- 12. b) F 2
- 13. c) Digoxin Digitalis purpuria Cardiac tonic
- 14. b) PHAs and PHB
- 15. a) Seed shape – Chromosome number 6
- 16. Biosafety is the prevention of large-scale loss of biological integrity, with a focus on protecting both ecological systems and human health. It encompasses measures and protocols designed to prevent harmful effects from biotechnological research, genetic engineering, and the use of genetically modified organisms on the environment and human populations. Biosafety includes containment procedures, risk assessment, and regulatory frameworks to ensure that biological research and its applications do not pose threats to biodiversity or public health.
- 17. Genetic Engineering, plant tissue culture, protoplasmic fusion, Molecular marking and DNA finger printing.
- 18. Zoophily refers to pollination that is mediated by animals, particularly insects. In zoophilous flowers, various animal pollinators such as insects, birds, bats, and other fauna transfer pollen from one flower to another while visiting flowers for nectar, pollen, or other rewards. Zoophilous flowers typically possess characteristics that attract these animal pollinators, including bright colors, fragrant odors, nectar production, and accessible pollen. This mode of pollination is highly effective in promoting cross-pollination and genetic diversity. The majority of flowering plants are zoophilous, with insects being the most common and important pollinators in terrestrial ecosystems.
- 19. The Genome Project is a comprehensive research initiative in which the entire genome of an organism, particularly plants, is systematically analyzed using advanced sequence analysis techniques and sequence homology comparisons with genomes of other organisms. This project involves determining the complete DNA sequence of an organism's genome and identifying all genes and their functions. Examples of plant genome projects include the analysis of Chlamydomonas, an algae, Arabidopsis thaliana, a model dicot plant, and important crop plants such as rice and maize. These genome projects provide fundamental information about gene organization, function, and evolution, serving as reference datab…
- 20. There is a gradual decrease in energy transfer at successive tropic levels from producers to the upper levels. Therefore, the pyramid of energy is always upright.
- 21. Sodium molybdate Cupric sulphate Cobaltous chloride.
- 22. Abiotic components play vital role in an ecosystem. The total inorganic substances present in any ecosystem at a given time is called standing quality (or) standing state.
- 23. The process is uncertain since it depends on external agencies. Various devices are needed to attract the pollinating agents.
- 24. Genes are the functional units of inheritance and the basic units of heredity that carry biological information. A gene is a segment of DNA that codes for a specific protein or trait and is responsible for transmitting biochemical, anatomical, and behavioral characteristics from parents to offspring. Genes exist in different forms called alleles, which can produce variations in traits. They are located on chromosomes and are replicated and passed on during cell division and reproduction. Through genes, hereditary information is encoded and expressed, determining the physical and functional characteristics of organisms.
- 25. Totipotency refers to the inherent capacity of a single plant cell, or a small group of cells (an explant), to dedifferentiate and then redifferentiate to regenerate an entire, complete, and genetically identical plant. This means that any living plant cell, whether it is a somatic cell from the root, stem, leaf, or even a specialized cell, has the potential to develop into a whole organism under appropriate conditions. This remarkable ability is fundamental to plant tissue culture techniques, enabling scientists to propagate plants asexually, produce disease-free plants, and genetically modify crops on a large scale. Therefore, totipotency is best described as the capacity to generate a…
- 26. Codominance is a pattern of inheritance in which both alleles of a gene are fully and simultaneously expressed in the heterozygous individual without any blending or modification of their effects. When an organism inherits two different alleles for a trait, both alleles contribute equally to the phenotype, and both gene products are observable in the organism. Unlike incomplete dominance where the phenotype is intermediate, codominance results in the distinct expression of both parental traits together. The human ABO blood group system is a classic example of codominance. In individuals with blood type AB, both the A and B alleles are expressed simultaneously, resulting in the presence of…
- 27. Breathing roots, also called pneumatophores, are special types of negatively geotropic roots that grow upward against gravity and possess specialized structures called pneumathodes. These roots are adapted to obtain sufficient aeration in waterlogged or anaerobic soil environments where oxygen availability is limited. Pneumatophores emerge above the water or soil surface, allowing oxygen to enter through the pneumathodes and reach the underground root system. This adaptation is crucial for plants growing in swampy or marshy habitats where the soil is saturated with water and oxygen is scarce. A prominent example is Avicennia, a mangrove plant that develops numerous breathing roots to surv…
- 28. Some junk DNA is made up of pseudogenes, once working but have lost their ability to make proteins. They are fossilized parts act as evidence for evolution.
- 29. A biotope refers to the physical environment or habitat of a community, including all the non-living factors such as climate, soil, water, light, and temperature that characterize a particular area. It is the abiotic component of an ecosystem. An ecotope, on the other hand, refers to the specific habitat and ecological niche occupied by an organism or a group of organisms. While biotope describes the general environmental conditions of a location, ecotope describes the precise ecological position and role of an organism within that environment, including both its physical habitat and its functional relationship with other organisms in the community.
- 30. Euploidy refers to a condition where the ploidy involves entire sets of chromosomes, meaning the chromosome number is an exact multiple of the haploid number. In euploidy, the balance of genes remains normal even though the total number of chromosomes increases. Examples of euploidy include triploidy (3x), tetraploidy (4x), and polyploidy (∞n). Euploid organisms typically have more regular chromosome behavior during meiosis compared to aneuploids. Aneuploidy, in contrast, refers to a condition where the diploid number is altered by the addition or deletion of one or more individual chromosomes, rather than entire sets. In aneuploidy, the chromosome number is not an exact multiple of the h…
- 31. It will bring in a great revolution like the computer revolution. It will lead to new scientific – revolutions that would change the lives & future of people. Major challenges will be met and major changes incomprehensible in many aspects of modern life.
- 32. Yes, clouds and dust particles can contribute to the greenhouse effect, making humid nights warmer than clear, dust-free, dry nights. Clouds, composed of water droplets or ice crystals, act like a blanket, trapping outgoing infrared radiation from the Earth's surface and re-emitting some of it back down, thus reducing heat loss. Dust particles, especially fine ones, can also absorb and scatter solar radiation and trap terrestrial heat. This phenomenon is a component of what is known as global warming. Global warming refers to the long-term increase in the Earth's average temperature due to the enhanced greenhouse effect caused by increased concentrations of greenhouse gases in the atmosph…
- 33. In pond ecosystem the bottom of the pyramid is occupied by the producers which are small organisms posses least biomass. So the value gradually increases towards the tip of the pyramid. Therefore pyramid of biomass is always inverted in shape.
- 34. Epigeal hydrophily is a specialized form of pollination that occurs at the water surface level, exemplified by the aquatic plant Vallisneria. Vallisneria is a submerged rooted hydrophyte that has evolved a remarkable mechanism for pollination despite living underwater. At the time of pollination, the female flowers are brought to the water surface by elongated coiled stalks that extend from the submerged plant. The female flower develops a cup-shaped depression on its surface that serves as a landing platform. Meanwhile, the male flowers detach from the plant and float freely on the water surface. As the male flowers drift on the water, they eventually settle into the cup-shaped depressio…
- 35. 1682 – Nehemiah Grew mentioned stamens as the male organ of a flower. 1694 – R.J. Camerarius described the structure of a flower, anther, pollen, and ovule 1761 – J.G. Kolreuter gave a detailed account of the importance of insects in pollination. 1824 – G.B. Amici discovered the pollen tube. 1848 – Hofmeister described the structure of pollen tetrad. 1870 – Hanstein described the development of embryos in Capsella and Alisma. 1878 – E. Strasburger reported polyembryony. 1884 – E. Strasburger discovered the process of Syngamy. 1899 – S.G. Nawaschin and L. Guignard independently discovered Double fertilization. 1904- E. Hanning initiated embryo culture. 1950 – D.A. Johansen proposed classif…
- 36. Ovules exhibit remarkable diversity in their orientation, form, and position of the micropyle relative to the funicle and chalaza, resulting in six major types. Orthotropous ovules are straight with the micropyle at the distal end and the funicle, body, and chalaza arranged in a single vertical line, as seen in Piperaceae. Anatropous ovules are completely inverted, with the body of the ovule bent so that the micropyle and funiculus lie close to each other, and this type is most common in dicots and monocots. Hemianatropous ovules have the body positioned transversely at a right angle to the funicle, as found in Primulaceae. Campylotropous ovules have the body curved at the micropylar end…
- 37. The albedo effect is due to greenhouse effect. Aerosols (suspension of fine solid (or) liquid particles in gas) with small particles is reflecting the solar radiation entering the atmosphere is known as Albedo effect. It reduces the temperature, photosynthesis and respiration The sulphur compounds present in the aerosol are responsible for acid rain due to acidification of rain water and destroy the ozone.
- 38. Food web is constructed to describe species interaction called direct interaction. It can be used to illustrate indirect interaction among different species. It can be used to reveal different patterns of energy transfer in terrestrial and aquatic ecosystems.
- 39. Gene transfer without the use of vectors is possible through chemical-mediated methods that facilitate the uptake of DNA into cells. Several chemicals are used to induce and enhance the uptake of foreign DNA into plant protoplasts and other cells. Polyethylene Glycol, commonly abbreviated as PEG, is one of the most widely used chemicals for this purpose. PEG acts by altering the permeability of the cell membrane, allowing DNA molecules to enter the protoplast more easily. Dextran Sulphate is another chemical used for similar purposes in gene transfer protocols. These chemicals work by creating temporary pores or disrupting the lipid bilayer of the cell membrane, facilitating the passage o…