CBSE Class 12 Biology HOTs Strategies For Enhancement In food Production

Very Short Answer Questions

Question. Mention the strategy used to increase homozygosity in cattle for desired traits.
Answer. Inbreeding

Question. Why are apical and axillary meristems used for tissue culture?
Answer. Because these are free from virus.

Question. Write the importance of MOET. 
Answer. MOET is used to increase the herd size in a short time. It also improves the chances of production of hybrids.

Question. Why is the South Indian sugarcane preferred by agriculturalists? 
Answer. South Indian sugarcane has thicker stem and higher sugar content.

Question. Write an alternate source of protein for animal and human nutrition. 
Answer. Single cell protein/Spirulina

Short Answer Questions

Question. How can we improve the success rate of fertilisation during artificial insemination in animal husbandry programmes?
Answer. The technology called MOET or Multiple Ovulation Embryo Transfer is used to increase the success rate.

Question. (a) List two advantages of keeping beehives in a crop field during flowering season.
(b) Name one annual and one perennial crop species favourable to beeswax collection.
OR
Give the scientific name of the most common species of honey bee reared in India. Why is it advantageous to keep beehives in crop-fields during flowering periods? 
Answer. (a) The most common species of honey bee reared in India is Apis indica. Honeybees are good pollinators of almost all the plants. The flowers in turn offer floral rewards like nectar and pollen grains. So, when beehives are kept in crop-fields during the flowering season, honey collection increases and in turn the crop yield also increases.
(b) Annual crop: Sunflower/Brassica Perennial crop: Apple/pear.

Question. How can healthy potato plants be obtained from a desired potato variety which is viral infected? Explain. 
Answer. Even though a plant is infected by a virus, the meristem (apical or axillary) is free of virus. So the meristem can be removed and grown in vitro, under sterile conditions and special nutrient/culture medium.

Question. Describe the technology that has successfully increased the herd size of cattle in a short time to meet the increasing demands of growing human population. 
Answer. Multiple ovulation embryo transfer technology (MOET) has successfully increased the herd size of cattle. The cow is administered with FSH to induce follicular maturation and super-ovulation to produce 6 to 8 eggs per cycle. It is then mated or artificially inseminated. The fertilised eggs are recovered non-surgically and transferred to surrogate mother where they develop into an improved variety.

Question. Plant breeding technique has helped sugar industry in North India. Explain how.
Answer. (ii) Sugarcane
• Saccharum barberi and Saccharum officinarum were crossed to obtain sugarcane varieties having desirable qualities.
• S. barberi was grown in north India and had poor sugar content and yield.
• S. officinarum did not grow in north India but had thicker stem and higher sugar content.
• The new sugarcane varieties formed by crossing the two varieties had the following qualities:
(a) high yield,
(b) thick stem,
(c) high sugar content,
(d) ability to grow in north India.

Question. High yielding cattle is a good solution for food enhancement. How does the MOET technology help to increase the herd size? 
Answer. • It is a programme for herd improvement in animals like cattle, sheep, rabbits, buffaloes, mares, etc.
• High milk-yielding breeds of female have been bred with high quality (lean meat with less lipid) meat-yielding bulls to increase herd size in lesser time.
Procedure
(i) A cow is administered hormones with FSH-like activity to induce follicular maturation and super-ovulation.
(ii) The cow produces i6n−s 8te aodnoeef eggggs produ ncoerdmally.
(iii) It noisw , ei ther ma wteidth an elite bour lal rtificial inseminatio n cairs roieudt.
(iv) When the fertilised eggs attain 8−32 cells stage, they are non-surgically removed and transferred to a surrogate mother.
(v) The genetic mother can now be again super-ovulated.

Question. Discuss the role of fishery in enhancement of food production.
Answer. Fishery is an industry related to the catching, processing and selling of fish, shellfish or other aquatic animals. Fishes are rich in proteins, vitamins and minerals, and are considered as complete food. Fish liver oil is used in medicine industry. A large part of human population depends on fish and fish products and other aquatic animals such as prawn, crab, lobster, edible oyster, etc., for food. Fishery provides income and employment to a large number of fishermen in coastal states.

Question. By taking two examples explain how has biofortification helped in improving food quality.
Answer. Biofortification has improved protein content and quality, oil content and quality, vitamin content, micronutrients and mineral content. For example, Atlas 66 has been used as a donor for developing wheat varieties with improved protein content. Maize hybrids have been developed with increased amount of amino acids, lysin and tryptophan.

Question. In MOET technology, two ‘mothers’ are needed to produce one calf. Justify. 
Answer. In MOET technology, one mother cow is administered hormones to induce follicular maturation and superovulation. These fertilised eggs are transferred to the second surrogate mothers for development.

Question. Demand for mushroom as food has led to its culturing on a large scale. Similarly, it is perceived that microbes too would become acceptable as food. Identify a microbe which can be cultured as a food source and give the applicability of its culture in the given context.
OR
To reduce the percentage of population suffering from hunger and malnutrition, microbes are grown on a large scale to act as food supplements. Mention any two microbes used as food supplement and suggest their role. 
Answer. The two microbes used as food supplements are:
(i) Spirulina: Produces large quantities of food rich in protein, minerals, fats, carbohydrates and vitamins.
(ii) Methylophilus methylotrophus: 250 gm of this microorganism produces 25 tonnes of protein per day.

Question. Success rate of artificial insemination in cattle is fairly low. Identify any other mean to improve the successful production of hybrids. State the advantages of this technique.

Answer. Multiple Ovulation Embryo Transfer (MOET) technology can be used to improve production of hybrids. This technique produces 8-10 eggs at a time and the genetic mother is only available for superovulation. By this technique, herd size can be increased in a short time.

Question. Lifestyle diseases are increasing alarmingly in India. We are also dealing with large scale malnutrition in the population. Is there any method by which we can address both these problems? 
Answer. The answer to address both these problems is biofortification. This looks at improving food quality with respect to protein, oil, vitamin, micro-nutrient and mineral content. The oils need to be rich in omega-3 fatty acids which are good for heart. Similarly, proteins should have more of lysine and tryptophan (essential amino acids). Many varieties of maize, carrots and spinach have been released with increased content of vitamin A, vitamin C, iron and calcium which fulfill the above criteria.

Question. How is outcrossing different from cross breeding? 
Answer. Outcrossing is the practice of mating animals of the same breed that have no common ancestors on either side of their pedigree up to 4-6 generations whereas cross breeding is the cross of one with superior females of another breed.

Long Answer Questions

Question. (a) Write the two limitations of traditional breeding technique that led to promotion of micropropagation.
(b) Mention two advantages of micropropagation.
(c) Give two examples where it is commercially adopted. 
Answer. (a) (i) Failed to keep pace with demand.
(ii) Failed to provide fast and efficient system of crop improvement.
(b) (i) Large number of plants can be developed in a short duration.
(ii) Production of genetically identical plants or somaclones.
(iii) Healthy plants can be recovered from diseased plants. (Any two)
(c) Tomato, banana, apple. (Any two)

Question. (a) “Fortification of crops is the need of the hour.” Give two reasons.
(b) Select one fresh water and one marine fish from the following:
Prawn; Catla; Mackerel; Lobster 
Answer. Fortification of crops is needed for following reasons:
(a) (i) To improve the nutritional quality,
(ii) to improve public health,
(iii) to prevent malnutrition, (Any two)
(b) Fresh water : Catla
Marine fish : Mackerel.

Question. Enumerate any six essentials of good, effective dairy farm management practices.
Explain the efforts which must be put in to improve health, hygiene and milk yield of cattle in a dairy farm. 
Answer. (i) The cattle in the dairy farm must be housed and fed properly.
(ii) Cleanliness should be maintained in the milking area.
(iii) The health of the dairy cattle should be of utmost importance and a veterinary doctor must visit regularly.
(iv) Regular inspections of the farm, maintaining records, identification and rectification of problems should be done along with maintaining precautionary measures.
(v) Milking should be done in a dirt-free area and all the sanitary conditions should be maintained.
(vi) High-yielding and disease-resistant breeds can be selec tetod maximis ebenefits.

Question. Mention the property of plant cells that has helped them to grow into a new plant in in vitro conditions. Explain the advantages of micropropagation. 
Answer. The property of plant cells that helped them to grow into a new plant is totipotency.
The advantages of micropropagation are:
(i) It is possible to achieve propagation of a large number of plants in very short durations.
Plants like tomato, banana, apple, etc., have been produced on commercial scale.
(ii) Healthy plants can be recovered from diseased plants by micropropagation. This is done by removing the meristem, which is disease-free and growing it in vitro. This has been done in banana, sugar cane, potato, etc.

Question. (a) Explain how to overcome inbreeding depression in cattle. 
(b) List three advantages of inbreeding in cattle.
(c) Name an improved breed of cattle.
Answer. (a) In order to overcome the cattle from inbreeding depression, selected animals of the breeding population should be mated with unrelated superior animals of the same breed or different breed. This helps in restoring the fertility and yield in the cattle.
(b) (i) Pure lines can be obtained.
(ii) Harmful recessive genes are exposed that are eliminated by selection.
(iii) Superior genes can be accumulated by inbreeding by eliminating undesirable genes.
(c) Jersey cow.

Question. Mention the cause and effect of inbreeding depression in cattle. How can it be overcome? Explain.
Answer. Inbreeding which refers to the mating between closely related individuals with the same breed for 4–6 generations causes inbreeding depression. Continued inbreeding, especially close inbreeding usually reduces the fertility and even productivity of the organism, this is called as inbreeding depression.
It can be overcome by mating the selected animals of breeding population with unrelated superior animals of same breed or different breed to restore fertility and yield.