Please refer to Biology For Strategies for Enhancement in Food Production Class 12 Biology Exam Questions provided below. These questions and answers for Class 12 Biology have been designed based on the past trend of questions and important topics in your class 12 Biology books. You should go through all Class 12 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 12 Biology Exam Questions Strategies for Enhancement in Food Production
Very Short Answer Questions
Question. Suggest the breeding method most suitable for animals that are below average in milk productivity.
Answer : Outbreeding/Outcrossing/Cross-breeding/Artificial insemination/Hybridisation.
Question. What is protoplast fusion?
Answer : The merging of protoplasts obtained from two different cells to form a hybrid protoplast is called protoplast fusion.
Question. Mention the role of ‘genetic mother’ in MOET
Answer : Genetic mother is used for superovulation to produce 6-8 eggs (under the influence of FSH).
Question. What is the purpose of animal breeding?
Answer : Purpose of animal breeding:
i. Increase in quantity of yield.
ii. Improving quality of produce.
Question. Where was IR-8 developed?
Answer : IR-8 was developed at International Rice Research Institute [IRRI] (Phillipins) .
Question. Write the scientific names of microorganism which produce high quantity of protein.
Answer : Methylophilus methylotrophus.
Question. Name the organism commercially used for the production of single cell protein.
Answer : Spirulina
Question. A certain tissue, of a plant, infected with TMV was used to obtain a new plant using tissue culture technique. Identify the technique used and reason out the possibility of obtaining a new healthy plant.
Answer : The technique used is tissue culture using meristematic tissue as this method produces virus free plants.
Question. How is a mule produced?
Answer : The mule is produced by breeding between male donkey and female horse (mare).
Question. Genetic variability is the root of any breeding programme. How does this variation occur?
Answer : i. All the wild varieties and relatives of the cultivated crops are collected and preserved.
ii. For their characteristics, evaluation of these genetic collections are done.
Short Answer Questions
Question. “Artificial insemination helps overcome several problems of normal mating”. Justify the statement and list a few of them.
Answer : This statement is completely justified.
i. It helps in selective breeding in animals.
ii. Semen of a single bull can be used to impregnate several females.
iii. Quality semen is available in preserved form all the time at all places.
iv. Frozen semen can be exported or imported. It is the most reliable method.
Question.a. Why are the plants raised through micropropagation termed as somaclones?
b. Mention two advantages of this technique.
Answer : a. Plants raised through micropropagation are genetically identical, hence the name somaclones.
b. i. Large number of plants are produced in short duration.
ii. Virus free plants are produced.
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 superovulation to produce 6 to 8 eggs. 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. High yielding cattle is a good solution for food enhancement. How does the MOET technology help to increase the herd size?
• 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.
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. Bottled fruit juices are clearer as compared to those made at home. Explain.
Answer : Bottled fruit juices contain enzymes pectinase and protease for making them clear.
Question. Explain the advantage of cross-breeding of the two species of sugarcane in India.
Answer : Saccharum barberi, grown in north India, had poor sugar content and yield, whereas Saccharum officinarum, grown in south India, had thicker stem and higher sugar content. The sugarcane species obtained after cross breeding these two species had thick stems, high sugar, high yield and ability to grow in north India.
Question. Enumerate four objectives for improving the nutritional quality of different crops for the health benefits of the human population by the process of “Biofortification”.
i. Improving protein content and quality.
ii. Improving oil content and quality.
iii. Improving vitamin content and quality.
iv. Improving micronutrient or mineral content.
Question. List the two steps that are essential for carrying out artificial hybridisation in crop plants and why.
a. Selection of parents: Only those plants should be selected which have desired traits.
b. Crossing over: Pollen grains from selected male plant is collected and transferred to the female plant after which it is bagged.
Question. In an agricultural field there is a prevalence of the following organisms and crop diseases which are affecting the crop yield badly:
a. White rust
b. Leaf and stripe rust
c. Black rot
Recommend the varieties of crops the farmers should grow to get rid of the existing problem and thus improve the crop yield.
Answer : (Image 9)
Question. How can pollen grains of wheat and rice which tend to lose viability within 30 minutes of their release be made available months later for breeding programmes?
Answer : The pollen grains can be stored in liquid nitrogen (−196°C). Such stored pollen grains do not lose their viability for years and can be used in breeding programmes.
Question. How does culturing Spirulina solve the food problems of the growing human population?
“Large scale cultivation of Spirulina is highly advantageous for human population.” Explain giving two reasons.
Answer : Microbes are being grown on an industrial scale as source of good protein.
Microbes like Spirulina can be grown easily on materials like waste water from potato processing plants (containing starch), straw, molasses, animal manure and even sewage, to produce large quantities and can serve as food rich in protein, minerals, fats carbohydrate and vitamins. Incidentally such utilisation also reduces environmental pollution and hence is environment friendly.
Question. How has mutation breeding helped in improving the production of mung bean crop?
Answer : Mutation breeding has helped in the production of disease resistant varieties of mung bean crops against yellow mosaic virus and powdery mildew.
Question. Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.
Answer : Steps for producing disease resistant plants are:
i. Screening of germplasm (for resistance sources)
ii. Hybridisation of selected parents
iii. Selection and evaluation of hybrids
iv. Testing and release of new varieties.
Question. State the disadvantage of inbreeding among cattle. How it can be overcome?
Answer : Continuous inbreeding reduces fertility and productivity. This is called inbreeding depression. This can be overcome by different breeds or individuals of the same breed with unrelated superior animals. This is done by mating.
Question. How are biofortified maize and wheat considered nutritionally improved?
Answer : Biofortified maize has twice the amount of amino acids, lysine and tryptophan,compared to existing hybrids and the wheat variety has increased protein content.
Question. Identify two ways in which Spirulina is helpful to mankind.
Answer : Spirulina is a source of food rich in protein, minerals, fats, carbohydrates and vitamins. It can grow on waste water from potato processing plants, straw, molasses, animal manure and even sewage, so it also reduces water pollution.
Question. What is outbreeding? Mention any two ways it can be carried out.
Answer : Outbreeding refers to the breeding of unrelated animals either of the same breed but not having common ancestors or of different breeds or even different species.
It can be carried out by:
iii. Interspecific hybridisation
Question. Differentiate between outbreeding and outcrossing.
Answer : Outbreeding is breeding of unrelated animals (having no ancestors for 4–6 generations) belonging to same breed or different breeds or different species.
Outcrossing is breeding within the animals of same breed having no common ancestors for 4–6 generation on either side of the pedigree.
Question. Plant breeding technique has helped sugar industry in North India. Explain how.
Answer : Sugarcane
• Saccharum barberi and Saccharum officinarum were crossed to obtain sugarcane varieties having desirable qualities.
• S. barberi was grown in north India, 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 2 varieties had the following qualities:
a. high yield,
b. thick stem,
c. high sugar content,
d. ability to grow in north India.
Long Answer Questions
Question. With advancements in genetics, molecular biology and tissue culture, new traits have been incorporated into crop plants.
Explain the main steps in breeding a new genetic variety of a crop.
i. Collection of variability on germplasm collection. All different wild varieties, species and relatives of cultivated species are collected and preserved.
ii. Evaluation and selection of parents to identify plant with desirable combination of character. Pure lines are created.
iii. Cross hybridisation among selected parents to produce hybrids.
iv. Selection and testing of superior recombinants. Selection among the progeny of the hybrids that have desired character combinations, superior to both the parents are self pollinated for several generations.
v. Testing, release and commercialisation of new cultivars. Newly selected lines are evaluated for yield and other agronomic traits of quality or disease resistance in research fields followed by testing the material in farmers fields.
Answer : Somaclones: The genetically identical plants developed from any part of the plant by tissue culture or micropropagation are called somaclones.
Question. State the objective of animal breeding.
Answer : Objective of animal breeding is to increase the yield of animal and improve the desirable qualities of the produce.
Question. Give an example of a new breed each of cattle and poultry.
Answer : Jersey/Hissardale—a new breed by crossing Bikaneri ewes and Mirano rams (cattle) and Leghorn (poultry).
Question. What is plant breeding? List the two steps the classical plant breeding involves.
Answer : Plant breeding is the purposeful manipulation of plant species in order to create plant types that are better suited for cultivation, give better yields and are disease resistant.
The two steps for classical plant breeding are:
i. Cross breeding or cross hybridisation of pure lines.
ii. Artificial selection to produce plants with desirable traits.