NCERT Class 12 Biology Chapter 12 Biotechnology and its Applications

NCERT Class 12 Biology Chapter 12 Biotechnology and its Applications Solutions to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 12 Biology Chapter 12 Biotechnology and its Applications and select need one. NCERT Class 12 Biology Chapter 12 Biotechnology and its Applications Question Answers Download PDF. NCERT Biology Class 12 Solutions.

NCERT Class 12 Biology Chapter 12 Biotechnology and its Applications

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Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 12 Biology Solutions are part of All Subject Solutions. Here we have given NCERT Class 12 Biology Chapter 12 Biotechnology and its Applications Notes, NCERT Class 12 Biology Textbook Solutions for All Chapters, You can practice these here.

Chapter: 12

BIOLOGY

UNIT – IV BIOTECHNOLOGY AND ITS APPLICATIONS

TEXT BOOK QUESTIONS ANSWERS

Q. 1. Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because

(a) bacteria are resistant to the toxin.

(b) toxin is immature.

(c) toxin is inactive.

(d) bacteria encloses toxin in a special sac.

Ans: (c) toxin is inactive.

Q. 2. What are transgenic bacteria? Illustrate using any one example.

Ans: Transgenic bacteria contain foreign gene that is intentionally introduced into its genome e.g. two DNA sequences. corresponding to A and B chains of human insulin were prepared and introduced in plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin.

Q. 3. Compare and contrast the advantages and disadvantages of production of genetically modified crops. 

Ans: Advantages of GM Crops are:

(i) Crops are more tolerant to abiotic stress like cold, drought, salt, heat.

(ii) Decrease dependence on chemical pesticides (pest-resistant crops).

(iii) Herbicide resistance.

(iv) Decrease in post-harvest losses.

(v) Increased efficiency of mineral usage by plants. This decreases exhaustion of soil fertility.

(vi) Enhanced nutritional value of food e.g. Vitamin A enriched rice.

(vii) GM plants provide alternative resources to industries like starches, fuels and pharmaceuticals.

Disadvantages: They supply allergens. and antibiotic resistance markers in the body. 

They cause genetic pollution in the wild relatives of the crop plants and affect our natural environment.

Q. 4. What are Cry proteins? Name an organism that produces it. How has man explored this protein to his benefit? 

Ans: Cry proteins are toxins encoded by cry genes in Bacillus thuringiensis bacteria. Man has exploited this protein to develop transgenic crops with insect resistance like Btcotton, Bt corn etc. 

Q. 5. What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.

Ans: Gene therapy is insertion of genes into individual cells or tissues to cure genetic diseases. First gene therapy was given in adenosine deaminase deficiency. Gene therapy adenosine deaminase deficiency: Introduction of Gene isolated from bone marrow cells producing ADA into cells at early embryonic stages.

Q. 6. Diagrammatically represent the experimental steps in cloning and expressing ahuman gene (say the gene for growth hormone) into a bacterium like E. coli?

Ans: Following steps are required to facilitate cloning into a vector:

(i) Origin of replication.

(ii) Selectable marker.

(iii) Cloning or recognition site.

(iv) Vectors for cloning genes in plants and animals.

Q. 7. Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?

Ans: rDNA technology can be used to remove oil from seeds by preventingthe synthesis of either glycerol or fatty acids. This can be done by the removal of specific gene responsible for the synthesis.

Q. 8. Find out from internet what is golden rice.

Ans: Golden rice is genetically engineered rice having pro-vitamin A.

Q. 9. Does our blood have proteases and nucleases?

Ans: No, human blood does not have nucleases and proteases. 

Q. 10. Consult internet and find out how to make orally active protei.. pharmaceutical. What is the major problem to be encountered?

Ans: Orally active protein pharmaceuticals contain encapsulation of protein or peptide in liposomes or formulations using penetration enhancers.

Major problem encountered is that proteases and acids present in the stomach juices denature the therapeutic protein and make it ineffective.

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