CBSE Class 12 Biology Strategies For Enhancement In Food Production Question Bank

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Biology: Chapter 9 – Strategies for Enhancement in Food Production (Question Bank)

Why is inbreeding necessary in animal husbandry?

Answer: Inbreeding increases homozygosity. It is necessary to develop a pure line of animals, and to evolve the breed with the desirable traits (such as high milk yield or high growth rate) by selecting the superior males and females and mating them.

Name two fungal diseases of crop plants.

Answer: Brown rust of wheat, smut of wheat, red rot of sugarcane and late blight of potato (any two).

Which product of apiculture is used in cosmetics and polishes?

Answer: Beeswax.

Semi-dwarf varieties of a crop plant were derived from IR-8. Name that crop.

Answer: Rice (paddy). The semi-dwarf varieties of rice such as Jaya and Ratna were developed from IR-8.

Write two qualities of Saccharum officinarum (sugarcane) grown in South India.

Answer: It has thicker stems and a higher sugar content. (But it does not grow well in the North Indian climate.)

A new breed of sheep was developed in Punjab by crossing two different breeds of sheep. Name the two breeds which were crossed and the new breed developed.

Answer: The Bikaneri ewes were crossed with the Marino rams, and the new breed is Hisardale.

Study the table given below and fill in the blanks marked A, B, C and D. (

Why are proteins synthesised from Spirulina called single cell proteins? What is the significance of such a protein?

Answer: Spirulina is a microorganism (a cyanobacterium) whose cells are used as a source of protein; the protein-rich food produced by the microbial biomass (single-celled organisms) is called single cell protein (SCP). Its significance is that it is a quick method of protein production, because the growth rate of the microbes is enormous. A 250 kg cow produces about 200 g of protein in a day, while 250 g of a microbe like Methylophilus methylotrophus can produce about 25 tonnes of protein in the same time. It provides a protein-rich diet for human beings, and it reduces the pressure on agriculture, and also helps to reduce the environmental pollution as it can be grown on the waste.

Differentiate between inbreeding and outbreeding in animals.

Answer:

Explain the process of somatic hybridisation.

Answer: Somatic hybridisation is the fusion of the protoplasts of the somatic cells of two different varieties or species, to produce a hybrid. For example, the fusion of the protoplasts of tomato and potato cells gives the 'pomato'.

1. The cell walls of the cells are removed by digestion with the enzymes pectinase and cellulase, to get the naked protoplasts.
2. The protoplasts of the two selected parents are fused, using polyethylene glycol (PEG) or an electric current.
3. The fused cell (the hybrid) is cultured on a suitable medium, where it regenerates the cell wall and begins to divide.
4. It develops into a callus and then into plantlets called somatic hybrids, which are then grown into the plants.

What is micropropagation? Why are plants produced by this technique called somaclones? Name any two food plants which are produced on a commercial scale using this method.

Answer: Micropropagation is the method of producing many plants in a short time through tissue culture (from a small part of the plant called an explant). The plants produced are genetically identical to the original plant from which they were grown, so they are called somaclones. Tomato, banana and apple are produced on a commercial scale by this method.

What is mutation? Explain the significance of mutation in plant breeding. Give an example of a disease-resistant variety of a cultivated plant induced by mutation.

Answer: Mutation is a sudden inheritable change in the characters of an organism due to a change in the sequence of bases in the gene(s). Mutation results in a new character or trait not found in the parental type. It can also be induced by using mutagens like gamma radiation. Such plant material is used directly, or used for breeding new varieties; in plant breeding, the useful mutations (for example high yield or disease resistance) are selected and used as parents. An example is the mung bean variety resistant to yellow mosaic virus and powdery mildew, which was developed by mutation breeding.

How can we improve the success rate of fertilisation during artificial insemination in animal husbandry programmes?

Answer: The Multiple Ovulation Embryo Transfer (MOET) technology can improve the success rate. In this procedure, a cow is given hormonal treatment (FSH) so that more than one ovum (6–8 eggs) is produced per cycle. After mating or artificial insemination, the embryos at the 8–32 celled stage are transferred to different surrogate mother cows. This technology has been successfully used for cattle, sheep, rabbits, mares and buffaloes.

Biofortification is the most practical means to improve public health. Justify the statement with examples.

Answer: Biofortification is the plant breeding programme designed to increase the vitamins, minerals, protein and healthier fat content in the crops. It improves the quality of the food and helps to prevent the 'hidden hunger'. Examples of fortified crops:

1. A new hybrid of maize that has twice the amount of the amino acids lysine and tryptophan.
2. Wheat variety Atlas 66, having a high protein content.
3. Rice with 5 times more iron than the normal amount. The IARI, Delhi, has released several crops rich in vitamins and minerals (such as vitamin A-rich carrot, spinach and pumpkin, and the vitamin C-rich bitter gourd, mustard and tomato).

The consumption of such biofortified food will improve the public health greatly.

What is meant by germplasm collection? Describe its significance in plant breeding programmes.

Answer: The collection of all the diverse alleles of all the genes of a crop plant is called germplasm collection. In plant breeding programmes, the germplasm provides the entire range of genes and alleles, and the characteristics which they express. The plant breeders select the most favourable characters of a particular gene and manipulate its transfer to a desirable parent.

To which product are the following related? (a) Blue revolution (b) White revolution (c) Green revolution

Answer:

1. Fish production
2. Milk production
3. Food grain (crop) production

Does apiculture offer multiple advantages to farmers? List its advantages if it is located near a place of commercial flower cultivation. Name the most common species of bee which is reared in India.

Answer: Yes. Apiculture (bee-keeping) is the maintenance of hives of honeybees for the production of honey. Honeybees also produce beeswax, which is used in industries such as the preparation of cosmetics and polishes. If bee-keeping is practised near the commercial flower cultivation, the advantages are:

1. Bees are pollinators of many crop species including flowering crops such as sunflower, Brassica and apple, so the crop yield increases.
2. It improves the honey yield, because the honeybees collect the nectar from the flowers for making honey.

The most common species reared in India is Apis indica (the Indian honeybee).

What is somatic hybridisation? Describe the various steps in producing somatic hybrids from protoplasts. Mention any two uses of somatic hybridisation.

Answer: Somatic hybridisation is the process of fusing the protoplasts of somatic cells of different varieties or species of plants to produce a hybrid.

Steps:

1. The cell wall of the fusing cells is removed by digestion with a combination of pectinase and cellulase to form protoplasts.
2. Fusion between the protoplasts of the selected parents is induced by the use of polyethylene glycol (PEG).
3. The resulting product is cultured on a suitable medium to regenerate the cell wall.
4. The cells obtained begin to divide and produce plantlets called somatic hybrids.

Uses:

1. Somaclonal variations can be created.
2. Plants which cannot be hybridised sexually can be hybridised by this method.
3. Allopolyploids can be raised by this method.

Nowadays capsules of Spirulina are used as food supplements. (i) Do you recommend the use of these capsules? Why? (ii) What values are expressed in the above statement?

Answer:

1. Yes. These capsules are rich in protein, and Spirulina can be produced in large quantities in less time, on waste water from potato processing plants, straw, molasses, etc., which also minimises the environmental pollution.
2. Problem solving, awareness about the environmental pollution, and knowledge about the recycling of wastes.

Dalip has a dairy farm. One day his friend Dev advises him to use artificial insemination to overcome several problems in developing better breeds of cow. Earlier his neighbour Devinder had advised him MOET for herd improvement. Dalip is ignorant and not able to decide. (i) Which technique should Dalip adopt? (ii) What is the advantage of this technique? (iii) What values are not exhibited by Dalip?

Answer:

1. MOET (multiple ovulation embryo transfer), as the success rate of this technique is high.
2. The herd size is increased in a short time, and the genetic mother is available for another round of superovulation.
3. Critical thinking, problem solving and decision making.