20. Breeding and Biotechnology 

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) pure line selection
(d) hybridisation.

2. Pusa Komai 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 a modified endogenous gene or a foreign gene are also known as ______.

(a) transgenic organisms
(b) genetically modified
(c) mutated
(d) both (a) and (b).

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

(a) n = 7 and x = 21
(b) n = 21 and x = 21
(c) n = 1 and x = 1
(d) n = 21 and x = 7

II Fill in the blanks.

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

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

6. Recombinant DNA technique made it possible to genetically engineer living organism.

7. Restriction endonucleases cut the DNA molecule at specific positions known as Molecular scissors.

8. Similar DNA fingerprinting is obtained for Identical twins.

9. Pleuripotent cells are undifferentiated mass of cells.

10. In gene cloning, the DNA of interest is integrated in a Vector [plasmid].

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

1. Raphano brassica is a man – made tetraploid produced by colchicine treatment.
Answer:           True.

2. The process of producing an organism with more than two sets of chromosome is called mutation.
Answer:           False.
Correct statement: 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.
Answer:           False.
Correct statement: A group of plants produced from a single plant through vegetative or asexual reproduction are called clones.

4. Iron fortified rice variety determines the protein quality of the cultivated plant.
Answer:           False.
Correct statement: Iron fortified rice variety determines the iron quality of the cultivated plant.

5. Golden rice is a hybrid.
Answer:           False.
Correct statement: Golden rice is a genetically modified plant.

6. Bt gene from bacteria can kill insects.
Answer:           True.

7. In vitro fertilisation means the fertilisation done inside the body.
Answer:           False.
Correct statement: In vitro fertilisation means the fertilisation done outside the body.

8. DNA fingerprinting technique was developed by Alec Jeffrey.
Answer:           True.

9. Molecular scissors refers to DNA ligases.
Answer:           False.
Correct statement: Molecular scissors refers to Restriction Enzymes.

IV. Match the following:

Column A

Column B

1. Sonalika

(c) Semi-dwarf wheat

2. IR-8

(e) Semi-dwarf Rice

3. Saccharum

(b) Sugarcane

4. Mung No. 1

(a) Phaseolus mungo

5. TMV-2

(d) Groundnut

6. Insulin

(h) the first hormone produced using rDNA technique

7. Bt toxin

(f) Bacillus thuringienesis

8. Golden rice

(g) Beta carotene

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

(a) The assertion is correct and the reason is wrong.
(b) Reason is correct and the assertion is wrong.
(c) Both assertion and reason are correct.
(d) Both assertion and reason are wrong.

1. Assertion: Hybrid is superior to either of its parents.
Reason: Hybrid vigour is lost upon inbreeding.
Answer:
(a) The assertion is correct and the 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 are wrong.

3. Assertion: rDNA is superior over hybridisation techniques.
Reason: Desired genes are inserted without introducing the undesirable genes in target organisms.
Answer:
(c) Both assertion and reason are correct.

VI. Answer in a Sentence

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

Atlas 66, a protein-rich variety, having higher dietary fibre and protein.

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

Dee-geo-woo-gen a dwarf variety from China.

3. Define genetic engineering.

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

4. Name the types of stem cells.

Embryonic stem cells and somatic stem cells are the types of stem cells.

5. What are transgenic organisms?

Plants or animals expressing a modified endogenous gene or a foreign gene are called transgenic organisms.

6. State the importance of biofertiliser.

Biofertilizer adds nutrients through the natural process of nitrogen fixation, stimulate the plant growth through the synthesis of growth-promoting substance.

VII. Short Answer Questions

1. Discuss the method of breeding for disease resistance.

Plant diseases are caused by pathogens like viruses, bacteria and fungi. This affects crop yield. To develop disease-resistant varieties of crops, that would increase the yield and reduce the use of fungicides and bactericides are important. Some disease-resistant varieties are as follows:

Crop

Variety

Resistance to diseases

Wheat

Himgiri

Leaf and stripe rust, hill bunt

Cauliflower

Pusa Shubhra, Pusa Snowball K-1

Black rot

Cowpea

Pusa Komal

Bacterial blight

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

Sonalika, kalyan and sona are the three improved characteristic of wheat that helped India to achieve high productivity.

3. Name two maize hybrids rich in amino acid lysine.

Protina, Shakti and Rathna are lysine – rich maize hybrids, which are developed in India.

4. Distinguish between
(a) Somatic gene therapy and germline gene therapy.
(b) Undifferentiated cells and differentiated cells.
Answer:
(a) Somatic gene therapy and germline gene therapy.

Somatic gene therapy

Germline gene therapy

Somatic gene therapy is the replacement of the defective gene in somatic cells.

Germline gene therapy is the replacement of the defective gene in the germ cell (egg and sperm).

(b) Undifferentiated cells and differentiated cells.

Undifferentiated cells

Differentiated cells

Our body is composed of over 200 specialised cell types, that can carry out specific functions, eg. Neurons or nerve cells that can transmit signals. Pancreatic cells to secrete insulin. These specialised cells are called as differentiated cells.

The cells which are variable potency, undifferentiated or unspecialised mass of cells are called stem cells. The stem cells are undifferentiated or unspecialised mass of cells.

5. State the applications of DNA fingerprinting technique.

Applications of DNA Fingerprinting:
(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 the regenerative process?

Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury. In such situations, stem cells are used for the treatment of diseases, which is called stem – cell therapy. In treating neurodegenerative disorders like Parkinson’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.

Inbreeding:
When breeding or mating takes place between animals of the same breed, for about 4 – 6 generations, then it is called inbreeding. Superior males and superior females of the same breed are identified and mated in pairs. It helps in the accumulation of superior genes and the elimination of undesirable genes. Inbreeding depression is the continued inbreeding, which reduces fertility and productivity. Inbreeding exposes harmful recessive genes that are eliminated by selection.


Outbreeding:
The breeding of unrelated animals is outbreeding. The offsprings formed are called hybrids. The hybrids are stronger and vigorous than their parents. Cross between two different species with desirable features of economic value is mated. Mule is superior to the horse in strength, intelligence, ability to work and resistance to diseases, but they are sterile.

VIII. Long Answer Questions

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

  1. Increased production of milk by cattle.
  2. Increased production of egg by poultry.
  3. High quality of meat is produced.
  4. Increased growth rate in domesticated animals.

2. Describe mutation breeding with an example.

The mutation is defined as the sudden heritable change in the nucleotide sequence of DNA in an organism. The genetic variations brings out changes in an organism. The organism which undergoes mutation is called a mutant.
The factors which induce mutations are known as mutagens or mutagenic agents. The mutagens are of two types:
(a) Physical mutagens: Radiations like X – rays, a, P and Y – rays, UV rays and temperature, etc, which induce, maturations are called physical mutagens.

(b) Chemical mutagens: Chemical substances that induce mutations are called chemical mutagens, eg. Mustard gas and nitrous acid. The utilization of induced mutation in crop improvement is called mutation inbreeding.
Achievements of mutation breeding:

  • Sharbati Sonora wheat produced from Sonora – 64 by using gamma rays.
  • Atomica – 2 rice with saline tolerance and pest resistance.
  • Groundnuts with thick shells.

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

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:

  1. Protina, Shakti and Rathna are lysine rich maize hybrids (developed in India).
  2. Atlas 66, a protein rich wheat variety.
  3. Iron rich fortified rice variety’.
  4. Vitamin A enriched carrots, pumpkin and spinach.

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

The carbon copy or more appropriately, a clone means to make a genetically exact copy of an organism. ‘Dolly’ is the cloned sheep.



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.
The basic steps involved in gene cloning are:

  • Isolation of desired DNA fragment by using restriction enzymes.
  • Insertion of the DNA fragment into a suitable vector (plasmid) to make rDNA.
  • Transfer of rDNA into the bacterial host cell (Transformation).
  • Selection and multiplication of the recombinant host cell to get a clone.
  • Expression of the cloned gene in the 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 the treatment of various diseases have been developed on a commercial scale.
Pharmaceutical products developed by rDNA technique:

  1. Insulin used in the treatment of diabetes.
  2. Human growth hormone used for treating children with growth deficiencies.
  3. Blood clotting factors are developed to treat haemophilia.
  4. Tissue plasminogen activator is used to dissolve blood clots and prevent heart attack.
  5. Development of vaccines against various diseases like Hepatitis B and rabies.

IX. Higher Order Thinking Skills (HOTS) Questions

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

The list of character he will incorporate are:

  1. High yielding and better quantity
  2. Disease resistance
  3. Insects pest resistance
  4. Improved nutritional quality
  5. Short duration

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

·         Dwarfness is desired in cereals, so fewer nutrients are consumed by the crops.

·         Fertilizer is responsive.

·         Disease resistant varieties.

·         Insect and pest resistant crop varieties.

·         High levels of desirable nutrients like vitamins, proteins and minerals.

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

An organism having more than two set of chromosome is called polyploidy. It can be induced by physical agents such as heat or cold treatment, X-rays and chemical agents like colchicine. As organisms produced by polyploidy have more than two set of chromosomes they are gigantic.

4. ‘P’ is a gene required for the synthesis of vitamin A. It is integrated with the genome of ‘Q’ to produce genetically modified plant ‘R’.
(i) What is P, Q and R?
(ii) State the importance of ‘R’ in India.
Answer:
(i)  The P, Q and R:

  • P – Beta – carotene gene.
  • Q – Prevent vitamin A deficiency.
  • R – Golden rice.

(ii) Importance of rice in India:

  • Rice is the most important staple food for millions of people in developing countries like India.
  • Beta – carotene is produced in the endosperm of the grain. It could control the chronic health problems caused by vitamin A deficiency, especially among the poor in developing countries like India.