Important Questions Class 12 Biology Chapter 9

With the ever-increasing demand for food supply due to the population explosion, increasing food production has become a necessity. The application of biological principles to plant breeding and animal husbandry contributes significantly to human efforts to increase crop production. Furthermore, numerous new techniques, such as tissue culture techniques and embryo transfer (Multiple Ovulation Embryo Transfer), are being developed and practised in order to promote food production. Whereas plant breeding can be used to create varieties that are resistant to pathogens, increasing crop yield, animal husbandry ensures that food from animals and animal products are available by taking care of animals and breeding domestic animals using scientific principles.

Refer to Extramarks Important Questions Class 12 Biology Chapter 9 with answers that will help class 12 students to understand the chapter and its important questions as well.

CBSE Class 12 Biology Chapter-9 Important Questions

Study Important Questions for Class 12 Biology Chapter 9 – Strategies for Enhancement in Food Production

1 Mark Questions and Answers

Q1 Why is inbreeding necessary in animal husbandry?

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

Q2 Name two fungal diseases of Crop plants.

Ans: Crop fungi include brown rust of wheat, smut of wheat, red rot of sugarcane, and late blight of potato.

Q3 Which product of Apiculture is used in cosmetics and polishes?

Ans: Beeswax is a product of apiculture that is used in cosmetics and polishes.

Q4 Semi-dwarf varieties of a crop plant were derived from IR-8. Identify that crop.

Ans: The Paddy crop, also known as rice, is derived from IR-8.

Q5 Write two qualities of Saccharum officinarum (Sugarcane) grown in South India.

Ans: The stem of Saccharum officinarum is thicker and contains more sugar.

Q6 Name any two semi-dwarf varieties of wheat introduced into all wheat growing belt of India.

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

Q7 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.

Q8 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.

Q9 Name two better-yielding varieties of rice developed in India?

Ans: Jaya and Ratna are the two better-yielding varieties of rice developed in India.

Q10 Name the microbe that is grown for use as protein-rich food?

Ans: Methylophilus methylotrophs is a microorganism grown for protein-rich food.

2 Marks Questions and Answers

Q1 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.

Q2 Why are proteins synthesised from Spirulina called Single-celled Proteins? What is the significance of a protein like this?

Ans: A protein-rich meal produced by microorganisms is known as single termed protein (SCP) Spirulina is a type of bacteria that contains a high concentration of protein. Because microorganisms multiply so quickly, it provides a quick method of protein synthesis. As a result, it provides humans with a high-protein diet.

Q3 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:

It provides a protein-rich dietary supplement.
It relieves the strain on agriculture in terms of protein supply.
It aids in the reduction of pollutants in the environment.

Q4 Expand MOET. How is it carried out?

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

Hormones are given to a cow to cause follicular motivation and hyperovulation.
The cow is mated to a chosen bull.
Fertilised eggs are retrieved and delivered to a surrogate mother at the 8-32 celled stage.

Q5 What is aquaculture? Name an animal that can be multiplied by aquaculture.

Ans: Aquaculture is the culturing of plants and animals in freshwater or marine water. Examples – Shrimps, Oysters, Shellfish etc.

Q6 Give one difference between a hybrid and a somatic hybrid.

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

Q7 Differentiate between inbreeding and outbreeding in animals.

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

3 Marks Questions and Answers

Q1 What is micropropagation? Why are plants produced by this technique called some clones? Name any two food plants which are produced on a commercial scale using this method.

Ans: Micropropagation is a technique that uses tissue culture to grow a large number of plants. Somaclones are micropropagated plants that are genetically identical to the parent plant from which they arise. . On a commercial scale, this technique is used to grow tomatoes, bananas, and apples.

Q2 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: A mutation is an inheritable change in an organism’s characteristics caused by a change in the sequence of nucleotides in the gene (s). Mutation results in the development of a new character or characteristic that differs from the parental type. Mutagens, such as gamma radiation, have the potential to trigger it. These plant components are either used as it is or used to breed new varieties. Mung bean resistance to yellow mosaic virus and powdery mildew.

Q3 To which revolution, the 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.

Ans: Crop production is associated with the green revolution.

Q4 How can we improve the success rate of fertilisation during artificial insemination in animal husbandry programmes?

Ans: The Multiple Ovulation Embryo Transfer (MOET) techniques, in which a cow is given hormone therapy (FSH) so that it can generate more than one ovum (6-8) in each menstrual cycle, can improve fertilisation success rates. Embryos at the 8-32 celled stage are transplanted to surrogate cows following artificial insemination. This method has benefited cattle, sheep, rabbits, mares, and buffaloes.

Q5 What is apiculture? What are the requirements to consider for beekeeping?

Ans: Apiculture or bee-keeping is the care and production of honey bees for the extraction of honey and beeswax.

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

A thorough understanding of their nature and behaviour.
Choosing a good place for beekeeping.
Swarm catching and hiving.
Managing beehives at different times of the year.
Honey and beeswax handling and collecting

Q6 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 utilised to regenerate plants directly.” It involves the following steps:

Select a superior plant.
Obtaining appropriate cultural media.
Explant sterilisation and inoculation on culture medium at a regulated temperature in light.
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.
Acclimatisation: test tube-rooted plantlets are acclimatised in a greenhouse before being transplanted to the field.

5 Marks Questions and Answers

Q1 What do you mean by “Outbreeding”? What are the different methods employed for outbreeding?

Ans: The practice of breeding unrelated male and female animals is known as outbreeding. It can be done in the following ways:

i) Outcross: An outcross occurs when two animals of the same breed have no common ancestor on either side of their lineage for 4-6 generations. It is the most efficient method of breeding animals with lower-than-average milk output, beef cattle growth rates, and so on.

ii) Cross-Breeding: Crossing superior males of one breed with superior females of another breed. It enables the beneficial characteristics of two distinct breeds to be blended and used for commercial production, such as Hisardale, a new breed of sheep created by crossing bikaneri ewes with Merino rams.

iii) Interspecific Hybridisation: 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.

Q2 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 bees which is reared in India.

Ans: Apiculture, often known as beekeeping, is where bees are bred commercially in apiaries, an area where a lot of beehives can be placed. It is the practice of keeping honeybee colonies to produce honey and wax. Apiculture benefits farmers in a variety of ways. Beeswax is produced by honey bees and is utilised 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.

Important Questions Class 12 Biology Chapter 9