10th Science Unit 20 Book Back Answer

Samacheer Kalvi 10th Science Unit 20 Book Back Questions with Answers:

Samacheer Kalvi 10th Std  Science Book Back 1 Mark and 2 Mark Questions with Answers PDF in Science uploaded and available below. 10th Standard New Science Syllabus 2022 – Biology 20 Breeding And Biotechnology Science Book Back Answers available for both English and Tamil mediums. Tamil Nadu Samacheer Kalvi 10th Science Book Portion consists of  23 Units. Science Book Contain Physics 01- 06, Chemistry 07 – 11, Biology 12 – 22 and Visual Communications  23 units. Check Unit-wise and Full Class 10th Science Book Back Answers/ Guide 2022 PDF format for Free Download for both English and Tamil Medium. Samacheer Kalvi 10th Science Book back Solutions/Answers below:

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10th Science Book Back Answers

Unit 20 – Breeding And Biotechnology

I. Choose the best 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
Ans : (b) Mass selection

2. Pusa Komal is a disease-resistant variety of.
a) sugarcane b) rice c) cowpea d) maize
Ans : (c) Cowpea

3. Himgiri developed by hybridization and selection for disease resistance against rust pathogens is a variety of .
a) chilli   b) maize c) sugarcane d) wheat
Ans : (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
Ans : (a) IR 8

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)
Ans : (d) both (a) and (b)

6. We can cut the DNA with the help of
a) scissors   b) restriction endonucleases
c) knife        d) RNAase
Ans : (b) Restriction endonucleases

7. rDNA is a
a) vector DNA b) circular DNA
c) recombinant of vector DNA and desired DNA d) satellite DNA
Ans : (c) Recombinant of vector DNA and desired DNA

8. DNA fingerprinting is based on the principle of identifying sequences of DNA
a) single stranded    b) mutated    c) polymorphic   d) repititive
Ans : (d) Repititive

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
Ans : (d) Both a and b

10. In a hexaploid wheat ( 2n = 6 x = 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 = 7 and x = 7 d) 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: Plant breeding

2. A protein-rich wheat variety is. Ans: Atlas 66

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

4. The scientific process which produces crop plants enriched with desirable nutrients are called.
Ans: 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 : Atomita 2

6. technique made it possible to genetically engineer living organisms.   Ans: Genetic Engineering

7. Restriction endonucleases cut the DNA molecule at specific positions known as.
Ans : Restriction sites

8. Similar DNA fingerprinting is obtained for.   Ans : Paternity testing

9. cells are undifferentiated mass of cells. Ans : Stem

10. In gene cloning the DNA of interest is integrated in a . Ans: Vector DNA

III. True or False (Correct the Statement if it is false)

1. Raphanobrassica is a tetraploid man–made genus 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. The process of producing an organism with more than two sets of chromosome is called Polyploidy breeding.

3. A group of plants produced from a single plant through vegetative or asexual reproduction are called a pureline.
Ans.: False. 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. Amino acid fortified rice variety determines the protein quality of the cultivated plant.

5. Golden rice is a hybrid.
Ans.: False. Golden rice is a Genetically modified crop.

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

7. In vitro fertilisation means the fertilisation done inside the body.
Ans.: False. In vitro fertilisation means the fertilisation done outside the body.

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

9. Molecular scissors refers to DNA ligases.
Ans.: False. Molecular scissors refers to Restriction Endonucleases.




IV. Match the following:

Question 1.

Column A Column B
1. Sonalika (a) Phaseolus mungo
2. IR-8 (b) Sugarcane
3. Saccharum (c) Semi-dwarf wheat
4. Mung No. 1 (d) Groundnut
5. TMV-2 (e) Semi-dwarf Rice
6. Insulin (f) Bacillus thuringienesis
7. Bt toxin (g) Beta carotene
8. Golden rice (h) the first hormone produced using rDNA technique

Answer:

  1. (c) Semi-dwarf wheat
  2. (e) Semi-dwarf Rice
  3. (b) Sugarcane
  4. (a) Phaseolus mungo
  5. (d) Groundnut
  6. (h) the first hormone produced using rDNA technique
  7. (f) Bacillus thuringienesis
  8. (g) Beta carotene.

V. Assertion and Reason

a) Assertion is correct and the 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.
Ans : (c) Both assertion and reason is correct

2. Assertion: Colchicine reduces the chromosome number.
Reason: It promotes the movement of sister chromatids to the opposite poles.
Ans : (b) Reason is correct and the assertion 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

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