Important Questions for Class 12 Chapter 9: Strategies for Enhancement in Food Production

Enhancement of food production has become a necessity with the ever-growing demand for food supply due to the population explosion. The application of biological principles to plant breeding and animal husbandry plays a major role in boosting human efforts to increase crop production. Furthermore, in promoting food production, numerous new techniques such as tissue culture techniques and embryo transfer (Multiple Ovulation Embryo Transfer) are being developed and practised. Where plant breeding can be used to create varieties that are resistant to pathogens thereby increasing the yield of crops, animal husbandry, on the other hand, ensures to cater to the needs of food from animals and animal products by taking care of animals and breeding domestic animals through the application of scientific principles.

Given below are a few questions on Strategies for Enhancement in Food Production Class 12. The explanations are also provided for reference.

Very Short Answer Type Questions

Q.1. Why were millions of chickens killed in Assam, West Bengal, Maharashtra and Orissa recently?

A.1. The chickens were killed due to Bird flu.

Q.2. Can gamma rays be used in crop improvement programmes?

A.2. Analysis of plants is carried out in closed chambers. These plants are consequently tested for desired mutations to be induced to breed further. The irradiated plants do not possess any adverse effects of radiation, hence are not harmful and can be used.

Q.3. Why does the mating of two closely related animals after a few generations lead to loss of fertility and vigour in animal husbandry?

A.3. Since recessive alleles tend to get together and express causing harmful effects in the progeny. This is called inbreeding depression.

Q.4. Where and how is a man-made cereal developed? Give an example.

A.4. An example is Triticale. It is developed by a cross of the plants – common wheat (Triticum aestivum) and European rye (Secale cereale). It is used as a substitute for wheat in a few parts of the world.

Q.5. Fill up:

A.5.

Q.6. What is a hidden hunger?

A.6. Hidden hunger is the consumption of food that lacks nutrients specifically, micronutrients like vitamins and minerals.

Q.7. Why plants derived from protoplast culture are named somatic hybrids?

A.7. Since the plants are formed after the fusion of two different varieties of isolated protoplasts, they are known as somatic hybrids. Each protoplast possesses a desirable character to obtain a hybrid protoplast which can further be grown to form a plant.

Q.8. What is protoplast fusion?

A.8. The fusion of isolated protoplasts to form a somatic hybrid is called protoplast fusion. The hybrid thus formed has the characteristics of both protoplasts.

Q.9. Why are culture meristems easier to culture compared to permanent tissues?

A.9. Meristems are undifferentiated cells that divide continuously and they have thin and elastic walls thus suitable for tissue culture as opposed to permanent cells which have to be differentiated to be able to divide. They also possess thick walls.

Q.10. Why are proteins synthesized from single cell proteins, Spirulina?

A.10. Single cell proteins are proteins produced by microorganisms. One such unicellular microbe is the Spirulina. Thus the proteins produced by Spirulina are termed as single-cell proteins.

Q.11. What is aquaculture? Name an animal that can be multiplied by aquaculture.

A.11. Aquaculture is the culturing of plants and animals in freshwater or marinewater. Examples – Shrimps, Oysters, Shellfish etc.

Q.12. State the role of a veterinary doctor in the management of a poultry farm.

A.12. A veterinary doctor ensures safe and proper farm conditions to keep animals free from diseases and treats them in case they pick up a disease.

Q.13. Can plants obtained from micro-propagation be referred to as ‘clones’?

A.13. Yes, as they are genetically identical to each other and the parent plant.

Q.14. Give one difference between a hybrid and a somatic hybrid.

A.14. A hybrid is obtained by crossing two selected plants of the opposite sex whereas somatic hybrids are obtained by fusion of any protoplasts from two different species of plants which are further cultured.

Q.15. What is emasculation? When is it done and why?

A.15. It is the removal of stamens from the bisexual flower that is used as a female parent in plant hybridization. It is done so as to avoid self-pollination. It is to be done at the bud stage before the anthers dehisce.

Q.16. What are the two main limitations of the plant hybridization programme?

A.16. Limitations:

• Compatibility of parents

• Limited availability of identified disease-resistant genes in crops

• It is a tedious and time-consuming process

Q.17. Why are intergeneric crosses almost unknown and interspecific crosses rare in nature?

A.17. Male and female animals of two varied related species are mated in interspecific crosses and their fertility varies. In a certain case, the progeny may display desirable features of both the parents and may be of economic value. Example – A mule, whereas the female counterparts can breed with the species which is rare in nature. Intergeneric hybridization, on the other hand, is the cross of two different genera which is almost unknown in nature. They never form the complete zygote and are infertile.

Q.18. State a difference between aquaculture and pisciculture.

A.18. The farming of aquatic organisms is aquaculture while the rearing, breeding, and transplantation of fish under controlled conditions is called pisciculture.

Q.19. Justify the variable term ‘desirable trait’ with suitable examples.

A.19. The desirable trait can be different for different plants. Listed below are the traits incorporated:

• Higher tolerance levels in response to the environmental stress – bajra, maize, jowar are resistant to water stress

• Pathogen-resistant – Moong bean is resistant to powdery mildew and yellow mosaic virus

• Improved crop quality and high-yield – Atlas 66 utilized as a donor to develop wheat varieties with enhanced protein content.

Q.20. What is Biofortification?  How many methods of Biofortification are there?

A.20. It is the process of breeding crops with higher levels of vitamins and minerals, or higher protein and healthier fats to enhance and improve the overall public health aspect. The methodology of Biofortification involves two principle methods – Selective breeding and Genetic modification

Short Answer Type Questions

Q.1. Through the example of the H5N1 virus, explain how diseases are fast spreading due to globalization and increased movement of people.

A.1. Bird flu is a recent and significant issue which involves the aspect of global health. The influenza-A virus(H5N1) is mainly observed in birds and is contagious. It can be fatal and advances due to the increasing integration of countries i.e., globalization. It facilitates the virus to travel places without impediment. Once acquired by humans, it spreads across at a faster pace with afflicted people travelling, especially through air travel. This way it spreads throughout.

Q.2. What is the blue revolution?

A.2. It refers to the noticeable emergence of aquaculture as a significant and highly productive agricultural activity.

Q.3. Why and how does beehive help in enhancing the yield?

A.3. When cultivated in the fields of Brassica, apple, pear and sunflower, Beehives cause an increase in the pollination efficiency of flowering plants and hence improve the yield.

Q.4. List a method which can be used to deal with both malnutrition and lifestyle diseases.

A.4. Biofortification can be used to address both issues. It focuses on improving the quality of food through good quality i.e., by increasing oil, protein, vitamin, micronutrient and mineral content. These oils which are required to be rich in omega-3 fatty acids which are good for the human heart. Essential amino acids such as tryptophan and lysine are not synthesized by the body and need to be taken only through diet. The amino acids are the building blocks of protein.

Q.5. In animal husbandry programmes, how can the success rate of fertilization during artificial insemination be improved?

A.5. Through the Multiple Ovulation Embryo Transfer(MOET) program, a cow is administered hormonal treatment so as to produce more than one ovum per cycle. Post artificial insemination, the embryos at 8-32 celled state are then transported to surrogate mothers.

Q.6. Explain the germplasm collection. What are its advantages?

A.6. Germplasm is the collection of all the diverse alleles of all the genes of a crop plant. It offers the following:

• Provides entire alleles and genes to the breeders and also the characteristics which a plant expresses.
• Most favourable characters of a specific gene are selected by the breeder to manipulate it and transfer it to the desired parent.

Q.7. Which characteristic of wheat helped India to attain the green revolution?
A.7. The improved characteristics are as follows:

• High-yielding attribute

• Speedy yielding feature

• Semi-dwarf nature

• Resistant to diseases

Q.8. What features of plants can help resist pest and insect infestation?

A.8. Features are:

• Rendering the flowers nectarless

• On aerial parts of plants, increasing hair growth

• Facilitates plants to produce insect-killing chemicals

Q.9. Why is it easier to culture plant cells in vitro as compared to animal cells?

A.9. It is because plant cells have the ability to grow into a new plant and are termed totipotency. Animal cells are not totipotent. They also have a limited number of cell cycles after which they die. The presence of cell walls in plants also makes it easier to culture when compared to the animal cells.

Q.10. Why is the culture medium referred to as highly enriched laboratory soil?

A.10. It is a highly enriched laboratory soil as they provide carbon source such as sucrose, vitamins, inorganic salts, amino acids and cytokinins and auxins(growth regulators) for the plant to grow.

Q.11. Are de-differentiation and a higher degree of success attained in plant tissue culture experiment related to each other?

A.11. Yes, they are related. Plant tissue culture can be more successful as any tissue can be produced even from differentiated cells as when a cell dedifferentiates, it gets regressed back to its embryonic stage wherefrom it can again differentiate into any form of tissue.

Q.12. Giving an example to differentiate between a breed and a species.

A.12. Species is the building block of biological classification and a taxonomic rank. It is a collection of a large group of entities that are capable of interbreeding and producing fertile offsprings. Example – Cow, dog. A breed is a specific group of plants or animals that have homogenous behaviour, appearance and other characteristics which help in distinguishing plants and animals of the same species. Example – American Bulldog, Afghan Shephard.

Q.13. What is the utility of plants that are raised through clones of the parent plant?

A.13. Plants that are raised through tissue culture are useful as they are identical copies of the parent plant and help in the maintenance of the desired traits of the parent plant.

Q.14. State the significance of testing new plant varieties in a country like India.

A.14. Testing is carried out on farmer’s field for three growing seasons at least at different locations across all the agro-climatic zones where crops are usually cultivated. The material is assessed in comparison to the best local crop cultivator available which is referred to as a reference or check cultivator.

Q.15. What is ‘stress’ in plants? What are the types of stress in plants?

A.15. It can be defined as external factors that negatively influence plant productivity, growth, survival and reproductive capacity. These factors can broadly be classified into:

• Biotic or biological stress factors
• Environmental stress or abiotic factors – drought, temperature etc

Q.16. What is natural selection and artificial selection? How does artificial selection influence the evolution process?

A.16. Natural selection is a key mechanism in evolution and is a non-random, gradual process in which biological traits become common in a population as a function of a distinct characteristic, which acts as a sieve through which a few variations can pass. In artificial selection, plants and animals with desirable traits are considered and favoured for reproduction. Also known as selective breeding, it promotes traits suiting human preferences.

Q.17. How are pure lines created in animal husbandry?

A.17. Inbreeding of 4-6 generations is essential to evolve the pure line in any animal. It aids in the accumulation of superior genes and helps eliminate less desirable genes by promoting homozygosity.

Q.18. In the protoplast fusion experiment, name the physical barriers of a cell. How to overcome the barriers?

A.18. In protoplast fusion experiment, the cell wall is the most significant physical barrier. It can be overcome by treating it with pectinase and cellulase enzymes that have the potential to digest the cell wall and release the bare protoplast girdled by the cell membrane only.

Q.19. List a few examples of biofortified crops. How do they benefit society?

A.19. Some examples are Wheat, rice, spinach, maize and pulses

Benefits:

• Fortified wheat is high in protein content
• Maize hybrids have twice the amount of amino acids
• Fortified rice has high levels of iron
• Consumption of biofortified food improves public health
• If 2 or 3 nutrients are incorporated into a single crop it would benefit consumers to overcome many nutrient deficiencies prevailing.

Q.20. What is the difference between inbreeding and outbreeding animals?

A.20. Inbreeding refers to mating between individuals of the same species. Outbreeding refers to mating between individuals belonging to different breeds of the same species.

Long Answer Type Questions

Q.1. What are the various steps that a Botanist will undertake to release a new variety of plant?

A.1. Following are the steps:

• Collection of variability – Genetic variability is the root of any breeding programme. Preservation and collection of various wild varieties of species and variants of the cultivated species is a primary source for the productive exploitation of natural genes in a population. It has a germplasm collection.

• Selection and Evaluation of parents – The germplasm is assessed to identify plants with desirable traits. The selected plants thus obtained are multiplied and utilized in the process of hybridization. Wherever possible, pure lines are created.

• Cross-hybridization: Desired characters from selected parents are often combined from two different parents. It is a time consuming and a tedious process as pollen grains from the desired male plant have to collect and placed on the stigma of the selected female plants.

• Selection and Testing of Superior recombinants: Selecting plants having desired trait combination among progeny. It is crucial for the breeding objective and requires a scientific examination of the progeny. It yields plants that are superior to their parents, which are self-pollinated until they reach a state of uniformity so as to not segregate characters in the progeny.

• Testing, commercialization and release of new cultivators

Q.2. a. Why does a shift from grain to meat diets create more demand for cereals?

b. What is the name of this emerging area of research where a 250kg cow produces 200g of protein every day but 250g of Methylophillus methylotrophus can produce 25 tonnes of protein? State the advantages of this area of research.

A.2. (a) The shift creates demand for cereals since it takes 3-10kg of grains to produce 1kg of meat through animal farming

(b) The name of the research field is single cell protein. As a source of good protein, microbes are cultivated on a larger scale. For instance, microbes like Spirulina can easily be grown on wastewater from starch processing plants like molasses, potatoes, animal manure and sewage to generate it in larger quantities which can be served as food rich in micronutrients. It also reduces environmental pollution.

Q.3. In crop improvement programmes, how are tissue culture methods beneficial over conventional methods of plant breeding?

A.3. Tissue culture was developed as the conventional breeding method failed to keep pace with demand and to provide fast and efficient systems for crop improvement sufficiently. Advantages of tissue culture are as follows:

• Produces a large number of plantlets by micropropagation within a short period of time.

• All cells have a similar genotype and constitute a clone as they are derived from a single explant by mitotic division.

• By providing salts, toxins etc tolerance to stress can be obtained in culture medium in increasing dosage. The surviving cells are then selected to raise resistance in plants

• Through meristem culture, virus-free plantlets can be obtained

• From new plants, embryos which do not survive inside seeds can be cultivated by tissue culture

Q.4. a) How are mutations beneficial for plant breeding? Discuss with an example
b) Explain in brief the technology that made us self-sufficient in food production.

A.4. a) Through the use of radiations (gamma radiations) and chemicals, it is possible to induce mutations artificially in plants. These plants are then selected and used to have desired characteristics as a source of breeding, which is referred to as mutation breeding. For instance, in moong bean, resistance to yellow mosaic virus and powdery mildew was induced through mutations.

b) Traditional farming yields limited biomass for animals and humans hence better management practices can cause an increase in the yield to a limited extent. As a technology, plant breeding helps to increase production to a large extent as it is significant in the manipulation of plant species to create desired plant types suited for cultivation with outcomes such as better yields and disease-resistant plants. This technology also supports the green revolution.

Q.5. How is plant cell totipotency being used for plant propagation and improvement?

A.5. It can be utilized by the following measures:

• It is possible to attain propagation of many plants in shorter durations with the application of these methods. Banana, tomato, apple etc are produced on a commercial scale.

• Through micropropagation, it is possible to recover healthy plants from diseased plants which are done by extracting meristems that are disease-free and growing it invitro which is done in potato, sugarcane etc.

Q.6. Explain the process of somatic hybridization.

A.6. Somatic hybridization takes place in the following steps:

1. Isolation and Fusion: The isolated protoplast is devoid of protoplast. Thus there are no barriers to protoplast fusion. This can be achieved by mechanical, induced or spontaneous fusion methods.
2. Hybrid Selection: After protoplast fusion, a heterogeneous mixture of unfused chloroplast, homokaryons and heterokaryons are obtained. These hybrid cells (heterokaryons) are then selected through biochemical, cytometric and visual methods.
3. Identification of Hybrid Cells: The somatic hybrids are identified by various molecular techniques such as RFLP, AFLP, PCR, etc.

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