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Chapter: 10th Science : Chapter 20 : Breeding and Biotechnology

Book Back Questions with Answers

I. Choose the correct answer II. Fill in the blanks III. State whether true or false. If false, write the correct statement IV. Match the following V. Understand the assertion statement, justify the reason given and choose the correct choice VI. Answer in a sentence VII. Short answers questions VIII. Long answers questions IX. Higher Order Thinking Skills (HOTS)

Breeding and Biotechnology (Science)

I.  Choose the correct answer


1. Which method of crop improvement can be practised by a farmer if he is inexperienced?

a. clonal selection

b. mass selection

c. pureline selection

d. hybridisation


2. Pusa Komal is a disease resistant variety of _________.

a. sugarcane

b. rice

c. cow pea

d. maize


3. Himgiri developed by hybridisation and selection for disease resistance against rust pathogens is a variety of __________.

a. chilli

b. maize

c. sugarcane

d. wheat


4. The miracle rice which saved millions of lives and celebrated its 50th birthday is _______

a. IR 8 

b. IR 24 

c. Atomita 2   

d. Ponni


5. Which of the following is used to produce products useful to humans by biotechnology techniques?

a. enzyme from organism

b. live organism

c. vitamins

d. both (a) and (b)


6. We can cut the DNA with the help of

a. scissors 

b. restriction endonucleases

c. knife

d. RNAase


7. rDNA is a

a. vector DNA

b. circular DNA

c. recombinant of vector DNA and desired DNA

d. satellite DNA


8. DNA fingerprinting is based on the principle of identifying ________

sequences of DNA

a. single stranded

b. mutated

c. polymorphic

d. repetitive


9. Organisms with modified endogenous gene or a foregin gene are also known as

a. transgenic organsims

b. genetically modified

c. mutated

d. both a and b


10. In a hexaploid wheat( 2n = 6 x = 42 ) the haploid (n) and the basic(x) number of chromosomes respectively are

a. n = 7 and x = 21

b. n = 21 and x = 21

c. n = 7 and x = 7

d. n = 21 and x = 7


II.  Fill in the blanks

1. Economically important crop plants with superior quality are raised by plant breeding.

2. A protein rich wheat variety is Atlas 66.

3. Colchicine is the chemical used for doubling the chromosomes.

4. The scientific process which produces crop plants enriched with desirable nutrients is called fortification.

5. Rice normally grows well in alluvial soil, but atomita 2 is a rice variety produced by mutation breeding that grows well in saline soil.

6. Gene therapy technique made it possible to genetically engineer living organism.

7. Restriction endonucleases cut the DNA molecule at specific positions known as restriction site.

8. Similar DNA fingerprinting is obtained for identical twins.

9. Callus cells are undifferentiated mass of cells.

10. In gene cloning the DNA of interest is integrated in a vector.


III.  State whether true or false. If false, write the correct statement

1. Raphano brassica is a man-made tetraploid produced by colchicine treatment. - True

2. The process of producing an organism with more than two sets of chromosome is called mutation. - False

The process of producing an organism with more than two sets of chromosome is called polyploidy.

3. A group of plants produced from a single plant through vegetative or asexual reproduction are called a pureline. - False

group of plants produced from a single plant through vegetative or asexual reproduction are called a Clone.

4. Iron fortified rice variety determines the protein quality of the cultivated plant - False

Amino acid rich fortified rice variety containing more amino acids determines the protein quality of the cultivated plant.

5. Golden rice is a hybrid. - False

Golden rice is a genetically modified plant.

6. Bt gene from bacteria can kill insects. - False

Bt gene from bacteria produces a toxin that can kill insects.

7. In vitro fertilisation means the fertilisation done inside the body. - False

In vitro fertilisation means the fertilisation taking place outside the body by artificial means.

8. DNA fingerprinting technique was developed by Alec Jeffrey. - True

9. Molecular scissors refers to DNA ligases. - False

Molecular scissors refers to restriction endonucleases.


IV.  Match the following

Column A Column B

1. Sonalika Phaseolus mungo

2. IR 8 Sugarcane

3. Saccharum Semi-dwarf wheat

4. Mung No. 1 Ground nut

5. TMV – 2 Semi-dwarf Rice

6. Insulin Bacillus thuringienesis

7. Bt toxin Beta carotene

8. Golden rice first hormone produced using rDNA technique


Column A - Column B

1. Sonalika - Semi-dwarf wheat

2. IR8 - Semi-dwarf Rice

3. Saccharum - Sugarcane

4. Mung No. 1 - Phaseolus mungo

5. TMV-2 - Ground nut

6. Insulin - first hormone produced using rDNA technique

7. Bt toxin - Bacillus thuringienesis

8. Golden rice - Beta carotene


V.  Understand the assertion statement, justify the reason given and choose the correct choice

a. Assertion is correct and reason is wrong

b. Reason is correct and the assertion is wrong

c. Both assertion and reason is correct

d. Both assertion and reason is wrong.

1. Assertion: Hybrid is superior than either of its parents.

Reason: Hybrid vigour is lost upon inbreeding.

Answer: a. Assertion is correct and reason is wrong

2. Assertion: Colchicine reduces the chromosome number.

Reason: It promotes the movement of sister chromatids to the opposite poles.

Answer: d. Both assertion and reason is wrong.

3. Assertion: rDNA is superior over hybridisation techniques.

Reason: Desired genes are inserted without introducing the undesriable genes in target organisms.

Answer: c. Both assertion and reason is correct


VI.  Answer in a sentence

1. Give the name of wheat variety having higher dietary fibre and protein.

Atlas 66 is a protein rich wheat variety.

2. Semi-dwarf varieties were introduced in rice. This was made possible by the presence of dwarfing gene in rice. Name this dwarfing gene.

The dwarfing gene was got from a dwarf variety of rice from China, named Dee-geo-woo-gen (DGWG).

3. Define genetic engineering.

Genetic engineering is the manipulation and transfer of genes from one organism into another to create a new DNA called as recombinant DNA (rDNA).

4. Name the types of stem cells.

Embryonic stem cells and Somatic stem cell.

5. What are transgenic organisms?

(i) Genetic modification refers to the alteration or manipulation of genes in the organisms using rDNA techniques in order to produce the desired characteristics.

(ii) The DNA fragment inserted is called transgene. Plants or animals expressing a modified endogenous gene or a foreign gene are also known as transgenic organisms.

6. State the importance of biofertiliser.

Importance of Biofertilizers : The term biofertilizer denotes all nutrient inputs of biological origin for plant growth Eg: Artificial inoculation of rice with cyanobacteria to increase soil fertility.

Significance :

(i) They are ecofriendly.

(ii) They do not cause pollution like artificial fertilizers.

(iii) Help to Safeguard natural resources.

(iv) They are cheaper and economical.


VII.  Short answers questions

1. Discuss the method of breeding for disease resistance.

Crop : Variety : Resistance to diseases

Wheat : Himgiri : Leaf and stipe rust, hill bunt

Cauliflower : Pusa Shubhra, Pusa Snowball K-l : Black rot

Cowpea : Pusa Komal : Bacterial blight

2. Name three improved characteristics of wheat that helped India to achieve high productivity.

S.No. : Varieties of wheat : Characteristics

1. Himgiri : Disease resistant variety - Resistant to disease like leaf and stipe rust, hill bunt.

2. Atlas 66 : Protein rich wheat variety.

3. Sonalika, Kalyan Sona : High yielding semi¬dwarf wheat variety.

The above mentioned characteristics seen in different varieties of wheat helped India to achieve high productivity.

3. Name two maize hybrids rich in amino acid lysine

Shakti, Rathna, Protina are maize hybrids rich in amino acid lysine.

4. Distinguish between

a) somatic gene therapy and germ line gene therapy

S.No. : Somatic gene therapy : Germ line gene therapy

1. It is the replacement of defective gene in somatic cells. : 1. It is the replacement of defective gene in germ cells (egg and sperm).

2. It is only beneficial to the patient but not carried to the next generation. : 2. The gene can be carried to the next generation but till date only somatic gene therapy has been targeted.

b) undifferentiated cells and differentiated cells

S.No. : Undifferentiated cells : Differentiated cells

1. They are of variable potency. : 1. These cells can carry out specific functions only.

2. They are unspecialised mass of cells and can divide to form more cells or give rise to differentiated cells. : They are specialised cell types and cannot form any other types of cell. They are formed from undifferentiated cells.

3. E.g: Embryonic stem cells. : 3. E.g: Adult stem cells.

4. Source of embryonic stem cells are early embryo. : 4. Adult stem cells can be got from amniotic fluid, bone marrow, etc.,

5. State the applications of DNA fingerprinting technique.

(i) DNA fingerprinting technique is widely used in forensic applications like crime investigation such as identifying the culprit It is also used for paternity testing in case of disputes.

(ii) It also helps in the study of genetic diversity of population, evolution and speciation.

6. How are stem cells useful in regenerative process?

(i) Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury.

(ii) In such situations stem cells are used for the treatment of diseases which is called stem-cell therapy.

(iii) In treating neurodegenerative disorders like Parkinsv./s disease and Alzheimer’s disease neuronal stem cells can be used to replace the damaged or lost neurons.

7. Differentiate between outbreeding and inbreeding.

S.No. : Outbreeding : Inbreeding

1. It is the breeding of unrelated animals. : 1. It refers to the mating of closely related animals within the same breed for about 4-6 generations.

2. The hybrids are stronger and vigorous than their parents. : 2. It helps to accumulate superior genes and eliminate undesirable genes.


VIII.  Long answers questions

1. What are the effects of hybrid vigour in animals.


Objectives of Animal Breeding :

Heterosis or Hybrid vigour: The superiority of the hybrid obtained by cross breeding is called as heterosis or hybrid vigour.

Effects of hybrid vigour in animal breeding :

(i) Increased production of milk by cattle.

(ii) Increased production of egg by poultry.

(iii) High quality of meat is produced.

(iv) Increased growth rate in domesticated animals.

Examples :

Cross breed of fowls

White Leghorn X Plymouth Rock


Hybrid fowl - yield more eggs

Cross breed of cows

Developed by mating the bulls of exotic breeds and cows of indigenous breeds.

Brown Swiss X Sahiwal


Karan Swiss - yield 2-3 times more milk than indigenous cows.

2. Describe mutation breeding with an example.


Mutation is defined as the sudden heritable change in the nucleotide sequence of DNA in an organism. It is a process by which genetic variations are created which in turn brings about changes in the organism. The organism which undergoes mutation is called a mutant.

Two types of mutagens : The factors which induce mutations are known as mutagens or mutagenic agents.

(i) Physical mutagens: Radiations like X-rays, α, β and γ-rays, UV rays, temperature etc. which induce mutations are called physical mutagens.

(ii) Chemical mutagens : Chemical substances that induce mutations are called chemical mutagens. Eg: Mustard gas and nitrous acid. The utilisation of induced mutation in crop improvement is called mutation breeding.

Achievements of mutation breeding :

Some achievements of mutation breeding are

(i) Sharbati Sonora wheat produced from Sonora-64 by using gamma rays.

(ii) Atomita 2 rice with saline tolerance and pest resistance.

(iii) Groundnuts with thick shells.

3. Biofortification may help in removing hidden hunger. How?


(i) Hidden hunger is a chronic lack of vitamins and minerals that often has no visible warning signs. People who suffer from it may not even be aware of it.

(ii) This can lead to severe consequences. Hidden hunger may lead to mental impairment, poor health and productivity or even death.

Biofortification :

Biofortification is the scientific process of developing crop plants enriched with high levels of desirable nutrients like vitamins, proteins and minerals. Some examples of crop varieties developed as a result of biofortification are given below:

(i) Protina, Shakti and Rathna are lysine rich maize hybrids (developed in India).

(ii) Atlas 66, a protein rich wheat variety.

(iii) Iron rich fortified rice variety.

(iv) Vitamin A enriched carrots, pumpkin and spinach.

4. With a neat labelled diagram explain the techniques involved in gene cloning.


Gene Cloning :

(i) A clone is a genetically exact copy of an organism.

(ii) In gene cloning, a gene or a piece of DNA fragment is inserted into a bacterial cell where DNA will be multiplied (copied) as the cell divides.

Basic steps involved in gene cloning :

(i) Isolation of desired DNA fragment by using restriction enzymes.

(ii) Insertion of the DNA fragment into a suitable vector (Plasmid) to make rDNA.

(iii) Transfer of rDNA into bacterial host cell (Transformation).

(iv) Selection and multiplication of recombinant host cell to get a clone.

(v) Expression of cloned gene in host cell.

Using this strategy several enzymes, hormones and vaccines can be produced.

5. Discuss the importance of biotechnology in the field of medicine.


Using genetic engineering techniques medicinally important valuable proteins or polypeptides that form the potential pharmaceutical products for treatment of various diseases have been developed on a commercial scale.

Pharmaceutical products developed by rDNA technique :

(i) Insulin used in the treatment of diabetes.

(ii) Human growth hormone used for treating children with growth deficiencies.

(iii) Blood clotting factors are developed to treat haemophilia.

(iv) Tissue plasminogen activator is used to dissolve blood clots and prevent heart attack.

(v) Development of vaccines against various diseases like Hepatitis B and rabies.


IX  Higher Order Thinking Skills (HOTS)

1. A breeder wishes to incorporate desirable characters into the crop plants. Prepare a list of characters he will incorporate

(i) Higher yield.

(ii) Resistance to diseases.

(iii) Resistance to insect pests.

(iv) Short duration crop.

(v) Tolerance to environmental conditions.

2. Organic farming is better than Green Revolution. Give reasons

Green revolution is the process of increasing food production through high yielding crop varieties and modern agricultural techniques in under developed and developing nations. This has increased production and helped India tide over food crisis. But this requires high yielding varieties of crops got by artificial methods like breeding, use of fertilizers and pesticides.

Some disadvantages have been listed below :

(i) This promotes monoculture of certain desired plant varieties.

(ii) Use of fertilizers I pesticides in excess alters the chemical composition of the soil.

(iii) All farmers cannot afford the cost.

(iv) Environmentalists felt that because of green revolution the soil was affected and certain traditional crops varieties have been neglected.

Organic Farming :

(i) In contrast organic farming avoids utilization of synthetic fertilizers, chemical pesticides and makes use of green manures, compost and biological pest control which do not harm the environment.

(ii) Further growing different plant species will lead to efficient use of nutrients and cause fewer outbreaks of disease.

(iii) Organic farming techniques like Inter cropping, use of companion plants will also increase biodiversity. Thus organic farming is stable, sustainable and beneficial for the future generations.

3. Polyploids are characterised by gigantism. Justify your answer.

(i) Polyploids are organisms having more than two sets of chromosomes.

(ii) Therefore depending on the degree of ploidy, the number of genes get multiplied. Therefore size of fruits vegetables are oversized.

(iii) These fruits and vegetables also have a market value and their vitamin and mineral content is also high.

4. ‘P’ is a gene required for the synthesis of vitamin A. It is integrated with genome of ‘Q’ to produce genetically modified plant ‘R’.

i. What is P, Q and R?

ii. State the importance of ‘R’ in India.

(i) P - Gene required for synthesis of vitamin A.

Q - Plant whose genome is being altered by integrating gene ‘P’.

R - Genetically modified fortified plant got by integrating gene ‘P’ in the genome of plant ‘S’.

(ii) Importance of ‘R’ in India: The transgenic plants are much stable, with improved nutritional quality, resistant to diseases and tolerant to various environmental conditions.

Objective : Improved nutritional quality in rice.

Gene inserted : Beta carotene gene (In humans, Beta carotene is required for the synthesis of Vitamin A)

Gene inserted : Golden Rice (genetically modified rice can produce beta carotene, that can prevent Vitamin A deficiency).


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