Important Questions for CBSE Class 12 Biology Chapter 9 - Strategies for Enhancement in Food Production 2024-25

1-Marks Questions:

1. Why is inbreeding necessary in animal husbandry? 

Ans: Inbreeding is important in animal husbandry because it enhances homozygosity.

2. Name two fungal diseases of Crop plants. 

Ans: Fungal infections that affect crops include brown rust of wheat, smut of wheat, red rot of sugarcane, and late blight of potato.

3. Which product of Apiculture is used in cosmetics and polishes?

Ans: The product manufactured from Apiculture that is used in cosmetics and polishes is beeswax.

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

Ans: The Paddy crop that is commonly known as rice is derived from IR-8. 

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

Ans: Saccharum officinarum has a thicker stem and higher sugar content. 

6. Name any two semi-dwarf varieties of wheat introduced into all wheat growing places of India?

Ans: Sonalika and Kalyan Sona are the two semi-dwarf varieties of wheat. 

7. What is Biofortification?

Ans: Breeding crops to boost their nutritional worth is known as biofortification. This can be accomplished using either traditional selective breeding or genetic engineering.

8. Give an example where mutation breeding has been Successfully carried out for introducing disease resistance.

Ans: Varieties of mung beans have been successfully developed that are resistant to yellow mosaic virus and powdery mildew.

9. Name two better yielding varieties of rice developed in India? 

Ans: The two yielding varieties best for the development of rice are Jaya and Ratna.

10. Name the microbe that is grown for use as protein-rich food?

Ans: Methylophilus methylotrophus is the microorganism grown for protein-rich food. 

11. Why is mutation breeding necessary for breeding for disease resistance? 

Ans: Mutation breeding is necessary because there is limited availability of disease-resistance genes in the crop plants and wide varieties.

12. Give any two commercial products produced from Apis species?

Ans: Honey and beeswax are the two commercial products that are manufactured from Apis species.

13. What is the major advantage of producing plants by micropropagation? 

Ans: The ability to develop a large number of plants in a short amount of time is a major benefit of microorganism-based plant production.

14. What are Somaclones?

Ans: Somaclones are genetically identical plants created by micropropagation of any component of a plant.

15. Name any two freshwater single-celled fishes? 

Ans: Rohu and Catla are the two fishes found in freshwater.

2-Marks Questions:

1. 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.

Ans: By crossing Bikaneri ewes and Merino rams, the new breed Hisardale was developed.

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

Ans: 

A - Leaf and Stripe rust, hill bunt.

B - Pusa swarnim (Karan rai).

C - Cowpea

D - Pusa Sadabahar

3. Why are proteins synthesized from Spirulina called Single celled Proteins? What is the significance of such a protein?

Ans: Single termed protein is a protein-rich meal generated by microorganisms (SCP) Spirulina is a type of bacteria that has a lot of protein. Because microorganisms multiply at such a rapid rate, it provides a fast method of protein synthesis. As a result, it provides a high-protein diet for humans.

4. Differentiate between inbreeding and outbreeding in animals.

Ans: Inbreeding occurs when animals of the same breed are bred together, whereas crossbreeding occurs when animals of different breeds are bred together.

5. Observe the process of Somatic hybridisation given below and fill in the blanks. (i),

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Ans: 

(i) Isolation of the protoplast of Tomato cell and Potato cell.

(ii) Somatic hybridisation.

(iii) Pomato

(iv) Somatic hybrid

6. What is single cell protein? What is its significance?

Ans: Single cell protein refers to the large-scale synthesis of edible proteins for humans and animals from microbes. It is significant because: 

1. It provides a protein-rich dietary supplement.

2. It relieves the strain on agriculture in terms of protein supply.

3. It aids in the reduction of pollutants in the environment.

7. Expand MOET. How is it carried out?

Ans: Multiple ovulation Embryo Transfer is referred to as Moet. It entails the following steps:

1. Hormones are given to a cow to cause follicular motivation and hyper ovulation.

2. The cow is mated to a chosen bull.

3. Fertilized eggs are retrieved and delivered to a surrogate mother at the 8-32 celled stage.

8. What is germplasm? Why is it necessary to have germplasm collection?

Ans: Germplasm is the genetic material that is passed down through the generations via germ cells. It refers to the total number of genes in an individual. It is used as a starting point for the development of various crops by breeders.

The primary goal of germplasm collecting is to preserve genetic variation in a certain plant or genetic stock for future use. 

Benefits of Collecting Germplasm:

• Many plant cell and tissue cultures may be cryopreserved and kept alive for several years before being used when needed.

• This approach can be used to preserve plant components from endangered species.

• It is an ideal way to keep cell cultures that produce secondary metabolites like antibiotics safe for a long time.

• Recalcitrant seeds (seeds that lose viability after being stored) can be kept for a long time.

• Disease-free plant materials can be frozen and propagated as needed.

• In civilizations, somaclonal differences are preserved.

• Rare germplasms created by somatic hybridization and other forms of genetic manipulation can be saved.

9. What is inbreeding depression? Why do self-pollinated crops not show the ill effects of inbreeding depression?

Ans: Inbreeding depression is a decrease in the biological fitness of a population's members as a result of inbreeding. Inbreeding depression is defined as a reduction or loss of fitness and strength induced specifically by inbreeding. In its simplest form, inbreeding depression occurs when relatives in a small groupmate, which reduces the population's capacity to endure and reproduce.

Self-pollination produces a significant number of plants that suffer from severe inbreeding depression and are toxic. Due to the decrease in strength and fertility, maintaining the breeding line after three to four generations is nearly impossible. These are mostly found in Alfalfa which belongs to the pea family and carrots.

10. What is interspecific hybridization. Give an example?

Ans: It is a form of outbreeding in which male and female animals of two different species are mixed to combine the good characteristics of both parents into one animal. For example, a mule is created by crossing a donkey and a female horse.

11. What are the advantages of breeding for disease resistance in plants?

Ans: Plant disease resistance breeding offers two advantages.

(i) Increase food output while minimizing disease-related losses.

(ii) Fungicides and bactericides are used less often.

12. Which part of the plant is best suited for making virus-free plants and why?

Ans: Apical and intercalary buds with apical meristem are the finest parts of the plant body for producing virus-free plants as they are virus-free.

13. What is artificial insemination? What are the advantages of this technique?

Ans: It is a procedure in which a breeder injects superior male sperm into the reproductive tract of a chosen female.

Advantages include:

1. Semen can be utilised right away or saved for later use.

2. Semen can be transferred frozen from one location to another.

3. The sperm from a single guy can be utilized on a large number of females.

14. Why was hybridization carried out between species of Sugarcane in North India & that grown in South India?

Ans: Saccharum barberi was cultivated in North India, but its sugar content and yield were low, whereas Saccharum officarum, which had a thicker stem and a higher sugar content, was cultivated in South India but was unable to germinate in North India. As a result, both species were hybridised to bring out the desired features found in these two varieties, such as high yield, thick stem, high sugar, and ability to grow in North India.

15. Name the variety developed and disease to which it is resistant in case of:-

(i) Brassica

(ii) Cowpea

Ans:

(i) Pusa swarnim, a white rust-resistant cultivar.

(ii) Bacterial blight-resistant Pusa Komal variant.

16. What is meant by the term "breed". What are the objectives of animal breeding?

Ans: Breed refers to a group of animals with similar ancestral characteristics such as size, general look, and so on.

Animal breeding goals include: 

(a) increasing animal output.

(b) Enhancement of the product's attractive features.

3-Marks Questions:

1. 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.

Ans: Micropropagation is a technique for growing a large number of plants using tissue culture. Somaclones are plants generated by micropropagation that are genetically identical to the parent plant from which they were developed. This technique is used to grow tomatoes, bananas, and apples on a commercial basis.

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

Ans: The mutation is a term used to describe a sudden inheritable change in an organism's characteristics caused by a change in the sequence of nucleotides in the gene (s). Mutation produces a new character or characteristic that is distinct from the parental type. Mutagens, like gamma radiations, can potentially be used to trigger it. Plant components like this are either utilized as is or used to breed new varieties. Yellow mosaic virus and powdery mildew resistance in mung beans.

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

Ans: The Multiple Ovulation Embryo Transfer (MOET) technique can boost fertilization success rates in which a cow is given hormone therapy (FSH) so that it can generate more than one ovum (6-8) in every menstrual cycle. After artificial insemination, the embryos at the 8-32 celled stage are transplanted to surrogate mother cows. Cattle, sheep, rabbits, mares, and buffaloes have all benefited from this technique.

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

Ans: Biofortification is a plant breeding programme that aims to enhance the amount of vitamins, minerals, higher protein, and better fats in crops. This initiative aims to enhance the quality of food. It's necessary to avoid concealed hunger. The following are some examples of fortified crops:

(i) New maize hybrid: has twice as much lysine and tryptophan as regular maize.

(ii) Atlas 66 wheat, which has a high protein level.

(iii) Rice has 5 times the average amount of iron. IARI Delhi has introduced a

number of vitamin and mineral-rich crops. The public's health will greatly improve if such biofortified foods are consumed.

5. What is meant by the Germplasm Collection? Describe its significance in plant breeding programmes.

Ans: Germplasm collection refers to the gathering of all the different alleles of all the genes in a crop plant. Germplasm supplies the whole set of genes and alleles, as well as the characteristics that they express, in plant breeding programs. 

Plant breeders choose the most advantageous characteristics of a gene and manage its transmission to the desired parent which depicts the significance of the programme. 

6. To which product, following products are related 

(a) Blue revolution 

Ans: Fish production is related to the blue revolution.

(b) White revolution 

Ans: Milk production is associated with the white revolution.

(c) Green revolution

Ans: Crop production is associated with the green revolution. 

7. What measures would you undertake to improve the quality & quantity of milk production?

Ans: Three variables influence the quality and amount of milk produced: genetic composition, nourishment, and environmental factors.

As a result, the following actions should be done to enhance livestock management:

(a) Shed: Sheds should be well-kept, well-ventilated, and have a pucca floor with a drainage channel.

(b) Healthy Meals: A well-balanced diet includes the right amounts of carbs, proteins, vitamins, minerals, and water. The feed is made up of two primary parts: 

(i) Roughage - fodder, hay, straw, and silage are examples of roughage.

(ii) Concentrates broken forage crops, grains, cereals, mullets, cotton, and seeds

(c) Water should not be contaminated with microorganisms etc. 

(d) Health Inspection: It necessitates frequent examination and adequate documentation.

8. What is "tissue culture"? What are the steps involved in tissue culture?

Ans: "Tissue culture is an experimental technique in which a mass of cells (callus) is generated from explant tissue and utilized to regenerate plants directly." It bills the following steps:

1. Selecting a superior plant.

2. Obtaining appropriate culture media.

3. Explant sterilization and inoculation on culture medium at a regulated temperature in light.

4. Explant callus induction.

Organogenesis is the process through which an organism develops.

Shoot formation is induced by a high cytokine: auxin ratio, whereas root formation is induced by a high auxin: cytokinin ratio.

6. Acclimatization: test tube rooted plantlets are acclimatized in a greenhouse before being transplanted to the field.

9. What are the measures that need to be taken for effective poultry farm management?

Ans: 

(i) It necessitates a brood home that is free of crowds, rainproof, adequately ventilated, and sheltered.

(ii) The brood home must be kept clean and disinfected.

(iii) Drainage system that works well.

(iv) Clean and fresh drinking water, as well as proper nutrition.

(v) Optimal egg production requires proper light control.

(vi) Because poultry is more sensitive to heat, precautions should be taken to avoid heat shock.

(a) Grass or low vegetation should be used to cover sheds.

(b) Sprinklers should be installed on the roof.

(c) Maximum ventilation is required.

(vii) Breeds that are disease-free and suitable for breeding should be chosen.

10. The steps in a programme are:-

Collection of germplasm, crossbreeding the selected parents, selection superior recombinant progeny and Testing, releasing and marketing new cultivars?

(i) What is this programme related to?

Ans: The programme is related to the breeding of plants.

(ii) Name two special qualities as the basis of the selection of progeny.

Ans: Resistance to diseases and yield are two of the most important factors to consider.

(iii) What was the outcome of the programme?

Ans: The outcome was the production of enhanced varieties.

(iv) What is the popular term given to this outcome? Also named the India Scientist who is credited with chalking out of this programme.

Ans: Hybrid is a prominent word for this result. This curriculum is ascribed to Dr S. Swamminathan, who originated it.

(v) Among the above $-$ mentioned step which is the most crucial step of this programme and why?

Ans: The most important phase in this approach is selecting superior progeny because it produces plants that are superior to both parents and can be self-pollinated for multiple generations.

11. What is apiculture? What are the requirements to consider for bee-keeping?

Ans: Apiculture is the production of honey bees for the extraction of honey or beeswax.

Beekeeping may be done everywhere there are enough bee pastures, such as natural bushes, fruit orchards, and cultivated crops. The following factors are critical for effective beekeeping: 

1. A thorough understanding of nature and bee behaviour.

2. Choosing a good place for beekeeping.

3. Swarm catching and hiving.

4. Managing beehives at different times of the year.

5. Honey and beeswax handling and collecting

12. What are the major steps involved in Plant breeding?

Ans: The steps in plant breeding are;

(i) Variation Collection: the gathering and preservation of all wild variations, species, and relatives of farmed species.

(ii) Germplasm Evaluation & Parent Selection: Germplasm is analyzed to find plants with suitable characteristics. The chosen plants are multiplied and put to use.

(iii) Selected Parent Hybridisation: Selected parents are hybridized so that their qualities can be integrated into the hybrid progeny.

(iv) Selection and Testing of Superior Recombinants: From the progeny, individuals with the required combination of characteristics must be chosen. These hybrids surpass both of their parents.

(v) Testing, Release and Commercialization of New Cultivars:

Growing these plants in a study field and documenting their performance under ideal circumstances of irrigation, fertilizers, and other agriculture techniques are used to evaluate them. The chosen plants are next evaluated for at least three growing seasons in the farmer's field. As a result, the item chosen is certified and published as a variety.

5-Marks Questions:

1. 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.

Ans: Apiculture, often known as beekeeping, is the practice of keeping honeybee colonies to produce honey. Apiculture benefits farmers in a variety of ways. Beeswax is produced by honey bees and is utilized in sectors such as cosmetics and polishes of various sorts. Beekeeping will be useful in the following ways if it is done in any location where commercial flowers are grown.

(i) Bees pollinate a wide range of crops, including blooming plants like sunflowers.

(ii) Honey Bees gather nectar from flowering plants to make honey, which increases honey yield.

The most prevalent species raised in India is Apis indica.

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

Ans: Somatic Hybridisation is the process of combining protoplasts of Somatic cells generated from various plant types or species to create a hybrid.

Steps:

(i) To generate protoplasts, the cell walls of fusing cells are digested with a mixture of pectinase and cellulase.

(ii) Polyethylene glycol is used to promote fusion between protoplasts from different parents (PEG).

(iii) To rebuild cell walls, the final product is grown in a suitable medium.

(iv) The cells acquired to begin to divide, resulting in somatic hybrid plantlets.

Applications: 

(i) Somaclonal variants can be generated.

(ii) The technique can be used to develop allopolyploids.

3. What do you mean by "Outbreeding"? What are the different methods employed for outbreeding?

Ans: Outbreeding is the practice of breeding unrelated males as female animals. It can be accomplished in the following ways:

(i) Outcross: An outcross is the mating of animals from the same breed who have no common ancestor on either side of their lineage for 4-6 generations. It is the most effective way of breeding animals with below-average milk output, beef cattle growth rates, and so on.

(ii) Cross-Breeding: This is when superior males of one breed are crossed with superior females of another breed. It permits the beneficial characteristics of two distinct breeds to be blended and used for commercial production, for example, Hisardale, a new breed of sheep produced by combining bikaneri ewes with Marino rams.

(iii) Interspecific Hybridization: male and female animals of two different related species are mated so that offspring might have desired characteristics from both parents, for example, a mule is formed by crossing a donkey and a female horse.

4. What is somatic hybridization - Explain the steps involved in the production of somatic hybrids?

Ans: The technique of fusing protoplasts of somatic cells generated from two distinct kinds or species of a plant on an appropriate nutritional culture medium under sterile conditions is known as somatic hybridization. Topato, a somatic hybrid created by fusing tomato and potato protoplasts, is one example.

The following stages are involved in somatic hybridization:-

(I) Protoplast isolation from two distinct plant types, each with a desired trait,

(II) When the cytoplasm of two protoplasts fuses, the cytoplasm coalesces. Even after cytoplasm fusion, the nuclei of two protoplasts may or may not fuse; protoplast fusion requires a suitable chemical termed fusogen, such as PEG or polyethylene glycol.

(III) Hybrid protoplasts form a new cell wall around themselves when conditions are favourable. A hybrid cell starts freshwater single-cell fish indefinitely to create a callus.

(IV) The callus is regenerated and transferred to fresh culture plates with appropriate culture media.

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