2nd PUC Biology Question Bank Chapter 12 Biotechnology and its Applications

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Karnataka 2nd PUC Biology Question Bank Chapter 12 Biotechnology and its Applications

2nd PUC Biology Biotechnology and its Applications One Mark Questions and Answers

Question 1.
Which soil bacteria produces Bt toxins?
Answer:
Bacillus thuringiensis.

Question 2.
Write the name of a nematode which infects roots of tobacco plants?
Answer:
Meloidegyne incognitia.

Question 3.
Write any two Bt resistant crops.
Answer:
Bt cotton, Bt soyabean.

Question 4.
What is molecular farming?
Answer:
Mass production of proteins and drugs in a bioreactor using genetically modified organisms is called molecular farming.

Question 5.
Expand GEAC.
Answer:
Genetic Engineering Approval Committee.

Question 6.
Name the bacterium which is used to produce insect-resistant plants by genetic engineering.
Answer:
Bacillus thuringiensis.

Question 7.
Name any disease against which vaccine is developed by recombinant DNA technology.
Answer:
Hepatitis B vaccine.

Question 8.
Name the technique which is used to detect HIV in suspected AIDS patient?
Answer:
PCR (polymerase chain reaction).

Question 9.
Name any two diseases for which transgenic mice are used as model organisms.
Answer:
Rheumatoid arthiritis and cystic fibrosis.

Question 10.
What is the difference between ‘Cry’ and ‘CRY
Answer:
Cry is the gene which codes for Bt-toxin which is an insecticidal protein, while CRY is the protein coded by cry genes.

Question 11.
Name any one disease for which gene therapy has been proved effective?
Answer:
Adenosine deaminase deficiency (ADA).

2nd PUC Biology Biotechnology and its Applications Two Marks Questions and Answers

Question 1.
What are genetically modified organisms? Name two factors on which their behaviour depends.
Answer:
Among plants, fungi, bacteria and animals, those that have had their DNA manipulated to possess and express an extra (foreign) gene, are known as genetically modified organisms. The two factors on which the behaviour of such organisms depend are,

• The nature of the gene transferred and
• The nature of the host cell.

Question 2.
To whom a patent is given?
Answer:
Patent is given for the following:

• For producing any new product or invention.
• For modifying and improving an earlier invention.
• To some specific technical know how.
• For a new designing concept.

Question 3.
Define the following:
1. DNA probe
2. Bio-piracy.
Answer:
1. DNA probe: DNA probe is a small DNA segment (20-50 bases) that can recognise complementary sequence in DNA molecule and thus allow identification and isolation of specific DNA sequence from an organism.

2. Bio-piracy: It is the use of bio-resources by multinational companies and other organisations without proper authorisation from the concerned countries and people without any compensatory payment.

Question 4.
Define gene therapy. Name a genetic disorder that is being treated using the technique of gene therapy.
Answer:
The technique of curing genetic diseases by replacing the defective genes by normal genes is called gene therapy W.F. Anderson is regarded as the father of gene therapy.

2nd PUC Biology Biotechnology and its Applications Three Marks Questions and Answers

Question 1.
What is molecular diagnosis? Explain.
Answer:
Molecular diagnosis: Effective treatment of diseases require early diagnosis and understanding of their pathophysiology.

Early diagnosis of diseases is not possible by conventional techniques like serum and urine analysis, sputum and stool analysis etc.
Modem techniques like rDNA, PCR, ELISA and RIA are used for early diagnosis.

• Infection of pathogens (viruses, bacteria etc) is suspected only when they produce disease symptoms.
• By this time the pathogens have multiplied in the body.
• But by PCR, amplification of nucleotide is possible and thus it is possible to detect bacteria virus even at very low concentrations.
  e.g.: HIV detection, genetic disorders

Modem techniques can also help in the identification of mutated genes in humans.

• A single stranded DNA or RNA, tagged with a radioactive probe is allowed to hybridise with its complementary DNA in a clone of cells, followed by detection by using autoradiography.
• The clone having mutated gene will not appear in the photographic film because the probe will not have complementary nitrogen base with the mutated gene.
• In ELISA test the infection of pathogen (viruses, bacteria, fungi, mycoplasm like organism) can detect the antibodies synthesised against the pathogen.

2nd PUC Biology Biotechnology and its Applications Five Marks Questions and Answers

Question 1.
What is gene therapy? Explain the types. Add a note on its applications?
Answer:
Gene therapy: The technique of curing genetic diseases by replacing the defective genes by . normal genes is called gene therapy W.F. Anderson is regarded as the father of gene therapy.

Types of gene therapy:
There are two main types of gene therapy, namely somatic cell gene therapy and germ line gene therapy.
(a) Somatic cell gene therapy: It is the replacement of the defective gene by a normal gene in somatic cells of the body. This therapy helps for treating the defective organs or tissues parts such as blood cells, liver cells, skin cells, lung cells etc. The genetic defects can be rectified only in that individual.

The replaced gene is not transmitted to the next generation. The diseases like SCID [Severe combined immune deficiency], Cystic fibrosis, Haemophilia, Cancer etc can be cured by somatic cell gene therapy.

(b) Germ line gene therapy: It is the replacement of defective genes by normal genes in germ cells to rectify the genetic disorders. This includes gene therapy in sperms, eggs, zygotes or early embryos. Any change made in the germ cells by gene therapy will be transmitted to the offspring.

Applications of gene therapy.

• The genes causing genetic disease can be removed and normal genes can be inserted.
• Non-functional organs can be made functional.
• Severe combined irnmuno deficiency [SCID] disease can be cured by introducing normal Adenosine deaminase gene.

Question 2.
What are transgenic animals? How are they obtained? Add a note on their significance.
Answer:
An animal developed by introducing the desired foreign gene is called a Transgenic animal.
Transgenic animals can be produced by the following methods.

• Microinjection of desired genes into pronucleus of the fertilized egg.
• Retroviral infection of fertilised eggs at 4 to 8 celled stages.
• Genetic alterations of embryonic stem cells [ESC] and their reintroduction into the blastocyst.

Transgenic animals are useful in biological, biomedical and biotechnological researches especially in animal husbandary, dairy and pharmaceutical industries.

Note: Transgenic animals are used as bioreactors for mass production of drugs and proteins. It is called genefarming or molecular farming.

Question 3.
Write a brief account on genetically engineered insulin.
Answer:
The process of synthesis of human insulin through recombinant DNA technology involves the following steps.

• Isolation of insulin gene [or desired gene],
• Insertion of insulin gene into plasmid.
• Transfer of recombinant plasmid to Ecoli cell.
• Selection or isolation and culture of Ecoli cells having r-DNA.
• Extraction of human insulin.

1. Obtaining the insulin gene: The human insulin gene can be obtained by collecting the mRNA for insulin protein from b cells of islets of Langerhans of pancreas. From this mRNA, complementary DNA [C-DNA] is synthesized by using reverse transcriptase or RNA dependant DNA polymerase enzyme.

2. Insertion of insulin gene into plasmid to produce rDNA: The plasmid pBR 322 is taken and is cut with the help of restriction endonuclease [Hind III], Now insulin, gene or cDNA for insulin is inserted by the side of b galactosidase gene. The ends are joined by using DNA plasmid is called recombinant plasmid or recombinant DNA.

3. Transfer of r-DNA or r plasmid into E.coli cells: A culture of E.coli cells are taken and mixed with r-DNAs or r-plasmids having gene, and the mixture is treated” with cold calcium chloride [CaCl₂], After some time the temperature of the solution is suddenly raised to 42°C This makes the plasma membrane of the host cell more permeable. This results in the easy entry of r-DNA into the E.coli cells.

4. Selection or isolation and culture of E.coli cells having r-DNA: E. coli cells that have received r-DNA for insulin are isolated from the mixture by using the specific antibiotic in the media. Those E.coli cells that have received r-DNA will survive as the resistance gene REN and the desired gene is inserted in this place.

Such cells DNA are selected with r-DNA by using replica plating technique. These selected E.coli cells are then cultured in bioreactors for large scale production. These cells produce insulin hormone in large quantities.

5. Extraction of insulin: The insulin synthesised in recombinant E.coli cells is human insulin. It contains B-galactosidase removed by treating with cyanogen bromide to form proinsulin. This proinsulin contains 3 chains designated as ‘A’ ‘B’ and ‘C’ chains.

This proinsulin is inactive due to the ‘C’chain which connects ‘A’chain [21 aa] and ‘B’chain [30aa], Chain ‘C’ is cut off by treating the proinsulin with trypsin. This process results in the formation of active human insulin or Huftiulin.