Samacheer Kalvi 10th Science Solutions Chapter 20 Pdf
Tamilnadu Board Samacheer Kalvi 10th Science Solutions Chapter 20: Tamilnadu State Board Solution Class 10 Science Chapter 20 – BREEDING AND BIOTECHNOLOGY.
Samacheer Kalvi 10th Science Solutions Chapter 20: Overview
Board |
Samacheer Kalvi |
Class |
10 |
Subject |
Science |
Chapter |
20 |
Chapter Name |
BREEDING AND BIOTECHNOLOGY |
Samacheer Kalvi 10th Science Solutions Chapter 20 Pdf
Exercise:
I choose the correct answer
1> Which method of crop improvement can be practiced by a farmer if he is inexperienced?
- a. clonal selection
- mass selection
- pureline selection
- hybridisation
Ans: a. clonal selection
Because, if a farmer is inexperienced then crop improvement can be done by clonal selection in which all the plants of clone are having similar both phenotype and genotype.
2> PusaKomal is a disease resistant variety of _________.
- sugarcane
- rice
- cow pea
- maize
Ans: c. cow pea
Because, PusaKomal is a disease resistant variety of cow pea.
3> Himgiri developed by hybridisation and selection for disease resistance against rust pathogens is a variety of __________.
- chilli
- maize
- sugarcane
- wheat
Ans: d. wheat
Because, Himgiri developed by hybridisation and selection for disease resistance against rust pathogens is a variety of wheat.
4> The miracle rice which saved millions of lives and celebrated its 50th birthday is _______
- IR 8
- IR 24
- Atomita 2
- Ponni
Ans:a. IR 8
Because, the miracle rice which saved millions of lives and celebrated its 50th birthday is IR 8.
5> Which of the following is used to produce products useful to humans by biotechnology techniques?
- enzyme from organism
- live organism
- vitamins
- both (a) and (b)
Ans: d. both (a) and (b)
6> We can cut the DNA with the help of
- scissors
- restriction endonucleases
- knife
- RNAase
Ans: b. restriction endonucleases
Because, to cut the DNA restriction endonuclease is helpful.
7> rDNA is a
- vector DNA
- circular DNA
- recombinant of vector DNA and desired DNA
- satellite DNA
Ans: c. recombinant of vector DNA and desired DNA
Because, rDNA is recombinant of vector DNA and desired DNA
8> DNA fingerprinting is based on the principle of identifying ————— sequences of DNA
- single stranded
- mutated
- polymorphic
- repetitive
Ans: d. repetitive
Because, DNA fingerprinting is based on the principle of identifying repetitive sequences of DNA
9> Organisms with modified endogenous gene or a foregin gene are also known as
(a) Transgenicor gansims
(b) Genetically modified
(c) Mutated
(d) Both a and b
Ans:(a) Transgenic organsims
Because, Organisms with modified endogenous gene or a foregin gene are also known as transgenic organisms.
10> In a hexaploidwheat (2n = 6 x = 42) the haploid (n) and the basic(x) number of chromosomes respectively are
- n = 7 and x = 21
- n = 21 and x = 21
- n = 7 and x = 7
- n = 21 and x = 7
Ans :d. n = 21 and x = 7
II Fill in the blanks
1> Economically important crop plants with superior quality are raised by_________.
Ans: Economically important crop plants with superior quality are raised bybreeding.
2> A protein rich wheat variety is ________.
Ans: A protein rich wheat variety is Atlas 66.
3> __________is the chemical used for doubling the chromosomes.
Ans: Colchicineis the chemical used for doubling the chromosomes.
4> The scientific process which produces crop plants enriched with desirable nutrients is called __________.
Ans: The scientific process which produces crop plants enriched with desirable nutrients is called Biofortification.
5> Rice normally grows well in alluvial soil, but _________ is a rice variety produced by mutation breeding that grows well in saline soil.
Ans: Rice normally grows well in alluvial soil, but Atomita- 2 riceis a rice variety produced by mutation breeding that grows well in saline soil.
6> __________ technique made it possible to genetically engineer living organism.
Ans: Recombinant DNA technique made it possible to genetically engineer living organism
7> Restriction endonucleases cut the DNA molecule at specific positions known as __________.
Ans: Restriction endonucleases cut the DNA molecule at specific positions known as molecular scissors.
8> Similar DNA fingerprinting is obtained for __________.
Ans: Similar DNA fingerprinting is obtained for identical twins.
9> __________ cells are undifferentiated mass of cells.
Ans: Pleuripotent cells are undifferentiated mass of cells.
10> In gene cloning the DNA of interest is integrated in a __________.
Ans: In gene cloning the DNA of interest is integrated in a Vector or 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.
Ans: True
2> The process of producing an organism with more than two sets of chromosome is called mutation.
Ans: False
Correct statement: The process of producing an organism with more than two sets of chromosomes is called polyploidy.
3> A group of plants produced from a single plant through vegetative or asexual reproduction are called a pureline.
Ans: 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
Ans: False
Correct statement: Iron fortified rice variety determines the iron quality of the cultivated plant.
5> Golden rice is a hybrid.
Ans: False
Correct statement: Golden rice is a genetically modified plant.
6> Bt gene from bacteria can kill insects.
Ans: True
7> In vitro fertilisation means the fertilisation done inside the body.
Ans: False
Correct statement: In vitro fertilization means the fertilization done outside the body.
8> DNA fingerprinting technique was developed by Alec Jeffrey.
Ans: True
9> Molecular scissors refers to DNA ligases.
Ans:Flase
Correct statement: Molecular scissors refers to Restriction enzymes.
V Match the following
Ans:
- Sonalika: semi-dwarf wheat
- IR-8: semi-dwarf rice
- Saccharum: sugarcane
- Mung No. 1: Phaseolusmungo
- TMV-2: groundnut
- Insulin: the first hormone produced using rDNA technique
- Bt toxin: Bacillus thuringienesis
- Golden rice: Beta carotene.
V> Understand the assertion statement, justify the reason given and choose the correct choice
- Assertion is correct and reason is wrong
- Reason is correct and the assertion is wrong
- Both assertion and reason is correct
- Both assertion and reason is wrong.
1> Assertion: Hybrid is superior to either of its parents.
Reason: Hybrid vigour is lost upon inbreeding.
Ans: 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.
Ans: d. both assertion and reason is wrong.
3> Assertion: rDNA is superior over hybridization techniques.
Reason: Desired genes are inserted without introducing the undesirable genes in target organisms.
Ans: 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.
Ans: Atlas 66, is the variety of wheat having higher dietary fiber and proteins.
2> Semi-dwarf varieties were introduced in rice. This was made possible by the presence of dwarfing gene in rice. Name this dwarfing gene.
Ans: Dee-geo-woo-gen is the dwarf variety from China. By using this dwarfing gene in rice the semi-dwarf varieties are introduced in the rice.
3> Define genetic engineering.
Ans: The manipulation and transfer of genes from one organism to other organism for creating new DNA named as recombinant DNA, which called as genetic engineering.
4> Name the types of stem cells.
Ans: There are two types of stem cells namely embryonic stem cells and somatic stem cells.
5> What are transgenic organisms?
Ans: Plants or animals expressing modified endogenous gene or a foreign gene are called as transgenic organisms.
6> State the importance of biofertilizer.
Ans: Biofertilizers stimulates the growth of plant by synthesizing growth promoting substances and also it adds nutrients by the natural process of nitrogen fixation.
VII Short answers questions
1> Discuss the method of breeding for disease resistance.
Ans:
- In plants, diseases may be caused by the pathogens like viruses, bacteria and fungi, due to which crop yield is affected. Hence, it is necessary to build the disease resistance which increases the crop yield and also will decrease the more use of fungicides and bacteroides.
- In wheat plants Himgiri is the variety which resist the disease like leaf and stipe rust and hill bunt.
- In cauliflower, PusaShubhra and Pusa Snowball K-1 are the varieties which resist the disease black rot.
- In cowpea plants, PusaKomal is the variety which resist the disease bacterial blight.
2> Name three improved characteristics of wheat that helped India to achieve high productivity.
Ans: Sonalika, Kalyan and Sona are the three improved characteristics of wheat that helped India to achieve high productivity.
3> Name two maize hybrids rich in amino acid lysine
Ans: Protina, Shakti and Rathna are amino acid lysine rich maize hybrids, developed in India.
4> Distinguish between
Ans:
a> Somatic gene therapy and germ line gene therapy :
Somatic gene therapy:
- Somatic gene therapy is the replacement of defective genes in somatic cells.
Germ line gene therapy:
- Germ line gene therapy is the replacement of defective gene in germ cells.
b> undifferentiated cells and differentiated cells:
Undifferentiated cells:
- The stem cells which are the cells of variable potency, undifferentiated and unspecialised mass of cells are called stem cells.
- And stem cells are undifferentiated and unspecialised mass of cells.
Differentiated cells:
- Our body is made up of 200 specialised cell types which carries specific functions.
- For example: nerve cells which transmits signals, heart cells which contract to pump blood, pancreatic cells which secrets insulin etc. All these specialised cells are called as differentiated cells.
4> State the applications of DNA fingerprinting technique.
Ans: If we want compare the genetic differences between the two individuals then DNA fingerprinting is the easiest and quickest method.
The applications of DNA fingerprinting method is as below:
- In forensic applications like crime investigation such as to identify the culprit, DNA fingerprinting method is widely used.
- It is also used for paternity testing in case of disputes.
- In the study of genetic diversity of population, evolution and speciation the DNA fingerprinting is most helpful.
5> How are stem cells useful in regenerative process?
Ans:
- Sometimes cells, tissues and organs may be damaged permanently or lost due to genetic conditions or disey or injury, in such conditions stem cells are used for treatment of diseases and it is called as stem cell therapy.
- In the treatment of the neurogenerative disorders like Parkinson’s disease and Alzheimer’s disease neuronal stem cells can be used for replacing damaged or lost neurons.
6> Differentiate between outbreeding and inbreeding.
Ans:
Inbreeding:
- Inbreeding includes the mating of closely related animals within the same breed for the 4-6 generations.
- In this breeding, superior males and superior females of the same breed are identified and mate in pairs.
- Inbreeding helps in accumulation of superior genes and eliminates desirable genes.
Outbreeding:
- Outbreeding is the breeding of unrelated animals and the offsprings formed are called as hybrid.
- Hence, in outbreeding the offsprings are stronger and vigorous than their parents.
- The two different species with desirable features of economic value are mated in this breeding.
- By crossing male donkey and female horse, mule is produced which is superior to horse in strength, intelligence, ability to work and resistant to disease but they are sterile.
VIII Long answers questions
1> What are the effects of hybrid vigour in animals?
Ans: Following are the effects of hybrid vigour in animal breeding:
- It increases the milk production by cattle.
- It also increases egg production by poultry.
- Due to it the high quality meat is produced.
- Because of it the growth rate increases in domesticated animals.
2> Describe mutation breeding with an example.
Ans:
- Mutation breeding is the sudden inheritable change in the nucleotide sequence of DNA in an organism. By mutation breeding genetic variations are created which later brings the changes in organism.
- The organism which undergo mutation breeding is called as mutant. The factors which induces mutations are called as mutagenic agents or mutagens.
- There are two types of mutagens namely chemical mutagens and physical mutagens.
1.) Physical mutagens:
Radiation’s like X-rays, alpha, beta and gamma rays, UV rays and temperature etc induces mutations are called as physical mutagens.
2.) Chemical mutagens:
Mustard gas and nitrous acids are the chemical substances which induces mutations are called as chemical mutagens.
3> Biofortification may help in removing hidden hunger. How?
Ans:
- Biofortification is the scientific process of developing crop plants which are enriched with high levels of desirable nutrients like vitamins, minerals and proteins.
- The examples of crop varieties developed due to biofortification are as follows:
- Protina, Shakti and Rathna are lysine rich maize hybrids developed in India.
- Atlas-66 is the protein rich variety of wheat.
- Iron riched fortified rice variety and vitamin A enriched carrots, pumpkin and spinach.
4> With a neat labelled diagram explain the techniques involved in gene cloning.
Fig. Genetic Engineering technique – Gene cloning.
- The carbon copy of an individual is called as clone. More accurately, clone means to make a genetically exact copy of an organism.
- In gene cloning, a gene or a piece of DNA fragment is inserted into the bacterial cell where DNA will be copied as cell division takes place.
The basic steps involved in the gene cloning are as follows:
- Desired DNA fragment is isolated by using restriction enzymes.
- Then DNA fragment is inserted into a suitable plasimd to make rDNA.
- After this, rDNA is transferred into bacterial host cell.
- Then selection and recombination of recombinant host cells takes place to get a clone.
- Finally expression of clone gene in host cell will occurs.
- By using this method several hormones, enzymes and vaccines may be produced
5> Discuss the importance of biotechnology in the field of medicine.
Ans:
- There are lots of applications of biotechnology in medical field.
- Medicinally important valuable proteins or polypeptides which forms the potential pharmaceutical products for treatment of various diseases will be developed by using genetic engineering technology.
- The pharmaceutical products developed by using rDNA technique are as given below:
- Mostly used insulin in the treatment of diabetes.
- For the treatment of children with growth deficiency, human growth hormone is used.
- To treat haemophilia blood clotting factors are also developed.
- Blood clots and prevent heart attack is dissolved by using tissue plasminogen activator.
- Vaccines are developed against the 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
Ans:
- The list of characters he will incorporate will be as follows:
- High yield and better quality with quantity.
- Disease resistance and insect resistance.
- Well-developed nutrition quality
- And short period
- High crop yield enriched with proteins, fibers and minerals
2> Organic farming is better than Green Revolution. Give reasons
Ans:
- Because, green Revolution is the process of increasing food production through high yielding crop varieties and modern agricultural techniques in underdeveloped and developing nation.
- Organic farming is better than green Revolution because of following reasons:
- Fertilizers are responsible.
- Disease resistant varieties are introduced.
- Insect and pest resistant varieties are also used.
- High level desirable nutrients such as proteins, vitamins and minerals.
- Dwarfness is desired due to which crop consumes fewer nutrients
3> Polyploids are characterized by gigantism. Justify your answer.
Ans: The organism having more than two set of chromosome is referred as polyploidy. And hence, the organisms produced by polyploidy are having more than two sets of chromosomes they are are gigantic i.e. characterized by gigantism.
Polyploidy can be introduced by using physical agents such as X-rays and chemical agents like colchicine.
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.
Ans: i> P is the beta carotene gene
Q is the prevent vitamin A deficiency
R is the Golden rice
ii> In developing countries like India rice is the most staple food used in daily diet.
The beta carotene is produced in the endosperm of the grain which controls the chronicle health problems caused due to vitamin A deficiency.
The rice food is cheaper and most requested in India.
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