Kerala Plus Two Botany Chapter Wise Previous Questions Chapter 5 Biotechnology and its Applications
Question 1.
Teacher asked Balan to write the principle of RNAi technology. Help him by describing the method.(MARCH-2010)
Answer:
The silencing of mRNA by a double stranded RNA (dsRNA) is called RNA interference.
Question 2.
Bt. Cotton is a well known example of application of Biotechnology in Agriculture. Bt. Cotton reduces use of pesticides. Explain. (MAY-2010)
Answer:
Bt. Cotton is a transgenic plant which contains the cry gene of bacillus thuringiensis. The cry gene produces cry protein which kills larvae of lepedopteran, diptern insects which attack cotton plants. This protein is inactive in bacteria and becomes active in the intestine of insects. When the cry gene is transferred to the plant it becomes resistant to the insects.
Question 3.
Adenosine deaminase (ADA) deficiency is a hereditary disease, where ADA, which is crucial for functioning of immune system is absent. Explain how ADA deficiency can be treated. (MAY-2010)
Answer:
Lymphocytes are taken from patient’s blood. It is grown invitro culture. By using retroviral vector functional ADA c DNA (from WBC of normal person) is introduced into invitro cultured lymphocytes of patients. These genetically engineered lymphocytes (corrected functional lymphocytes) are re injected to patients. If the ADA producing genes are introduce into cells at early embryonic stage it could be a permanent cure.
Question 4.
Bt toxin is produced by Bacillus thurungiensis that can kill certain insects. (MARCH-2011)
a) Name the bacterical gene that is producing this toxin.
b) Why the toxin produced by the bacterium is nontoxic to it?
Answer:
a) Cry-gene
b) Bt. toxin protein exist as inactive ie. protoxin in bacteria
Question 5.
Raju is a diabetic parient who takes insulin injections regulary. The insulin used by such patients is producted by genetically engineered organisms . Write the different steps involved in the production of insulin by genetic engineering. (MARCH-2011)
Answer:
1) Preparation of DNA sequences corresponding to A&B chain of human insulin.
2) Introduce them in plasmid of E.coli.
3) Products of A&B Chains are separated.
4) Combine A&B chains by creating disulphide bonds
Question 6.
Expand the common short forms used in biotechnology. (MAY-2011)
i) GEAC
ii) GMO
iii) PCR
iv) ELISA
OR
Bt toxins are not toxic to bacillus and Bt cotton plant but toxic to insects. Explain.
Answer:
i) GEAC – Genetic Engineering Approval Committee
ii) GMO – Genetically Modified Organisms
iii) PCR -Polymerase Chain reaction
iv) ELISA – Enzyme Linked Immuno Sorbent Assay
OR
The protein crystals are solubilised in the presence of alkaline pH of insect gut, hence becomes toxic to insects.
Question 7.
In human beings, certain diseases are caused due to genetic disorders. (MARCH-2012)
a) Name the method that allows the correction of a gene defect that has been diagnosed in a child or embryo.
b) How this method has been used for treating ADA (Adenosine deaminase) deficiency?
Answer:
a) Gene therapy
b) Introduction of functionalADAcDNAintothe lymphocyte of defective person.
Question 8.
Infection by nematodes cause threat to cultivation and yield loss of tobacco plants. A strategy has been developed at RNA level to control this infestation. (MARCH-2012)
a) Name the process.
b) Explain how this process works at the molecular level.
Answer:
a) RNA interference
b) In this process specific mRNA of the nematode is silenced due to a complementary ds RNA, that prevents the translation of mRNA
Question 9.
Using genetically modified crops, farmers can minimize use of insecticides and pesticides during cultivation. (MAY-2012)
a) Give name of one such genetically modified pest resistant crop.
b) Which gene is used for its production?
c) Name the source of pest resistant gene.
d) Write about its mode of action.
Answer:
a) Bt cotton
b) cry gene
c) Bacillus thuringiencis
d) The cry gene produce the insecticidal protein which solubilised in the alkaline PH of insect gut and make pores in the epithelial cells.This causes the death of insect.
Question 10.
Nita found that her Grandma used to inject human insulin that is genetically engineered. She wants to know how such insulin can be produced. Give her an idea about structure of insulin and production of genetically engineered insulin. (MAY-2012)
Answer:
It consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges.
It is necessary to prepare two DNA sequences corresponding to A and B, chains of human insulin and inserted in plasmids of E. coli to produce insulin chains. Chains A and B are produced separately, extracted and combined by creating disulfide bonds to form human insulin.
Question 11.
A novel strategy to prevent nematode infestation is (MARCH-2013)
based on ‘RNA interference’
a) Explain RNA interference.
b) Can you suggest, how it can be used for producing nematode resistant plant.
Answer:
a) it involves silencing of a specific mRNA of nematode Here the complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing).
b) Afterthe insertion of nematode-specific genes by Agrobacterium vectors into the host plant, it produce both sense and anti-sense RNA in the host cells. These double stranded RNA (dsRNA) that initiated RNAi and silenced the specific mRNA of the nematode.
Question 12.
Sophie was born with a genetic disorder – ADA deficiency. (MARCH-2013)
a) What is ADA deficiency?
b) Can you suggest methods to treat this ADA deficiency?
Answer:
a) Adenosine deaminase (ADA) deficiency
b) Bone marrow transplantation or gene therapy (Lymphocytes from the blood of the patient are cultured and functional ADA cDNA is introduced in it.Then, these cells are return back to the patient) .
Question 13.
Gene therapy aims in correcting diseases caused by defective genes. A Child is suffering from a disease due to deficiency of ADA enzyme. ADA gene which normally produce the enzyme is missing in the patient. Recommend any two methods to treat the child. (MAY-2013)
Answer:
Enzyme replacement therapy & Genetic engineering.
Question 14.
Expand the short forms used in Biotechnology. (MAY-2013)
1) PCR
2) ELISA
3) GEAC
4) GMO
Answer:
PCR – Polymerase Chain reaction
ELISA – Enzyme Linked Immuno Sorbent Assay GEAC – Genetic Engineering Approval Committee GMO – Genetically Modified Organisms
Question 15.
Bt Cotton is regarded as an important achievement of genetic engineering. What does Bt stands for? (MARCH-2014)
Answer:
Bacillus thuringiensis
Question 16.
Animals that had their DNA manipulated to possess and express foreign DNA are called transgenic animals. Write briefly any three benefits of such transgenic animals to human beings. (MARCH-2014)
Answer:
a) Transgenic mice are used to test the safety of the polio vaccine.
b) Transgenic cow, Rosie, produced human protein enriched milk (2.4 grams per litre).The milk contained the human alpha-lactalbumin It is the balanced product for human babies than natural cow- milk.
c) Transgenic animals that carry genes which make them more sensitive to toxic substances than non- transgenic animals. Toxicity testing in such animals get results in less time.
Question 17.
Consider you are appointed as biotechnologist in a National Institute: What are the basic steps to be designed to produce a genetically modified organism? (Hint 3 points) (MAY-2014)
Answer:
i) Identification of DNA with desirable genes.
ii) Introduction of the identified DNA into the host.
iii) Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
Question 18.
Pharmaceutical companies are producing large quantities of human insulin by genetic engineering. Briefly explain the process. (MAY-2014)
Answer:
1. Prepare two DNA sequences corresponding to A and B, chains of human insulin.
2. Introduced them in plasmids of E. coli to produce insulin chains.
3. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin.
Question 19.
in the 2012 children’s science congress one of the speaker summarized like this – if we are not vigilant, countries or individuals encash our resources as their right. (MAY-2014)
Explain this with an example
Answer:
Basmati rice is distinct for its aroma and flavour and 27 documented varieties of Basmati are grown in India. There is reference to Basmati in ancient texts, folklore and poetry, as it has been grown for centuries.
In 1997, an American company got patent rights on Basmati rice through the US Patent and Trademark Office. This allowed the company to sell a ‘new’ variety of Basmati, in the US and abroad.
Question 20.
In a class room seminar on cloning vectors, your friend asked to explain the steps to introduce the plasmid DNA to a bacteria cell, Microinjection and bilestics. Answer his questions. (MAY-2014)
Answer:
For this, bacterial cells must first be made ‘competent’ to take up DNA. This is done by treating them with a specific concentration of a divalent cation, such as calcium, Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 42°C (heat shock), and then putting them back on ice. This helps to introduce the plasmid DNA into bacterial cell.
Microinjection – In this recombinant DNA is directly injected into the nucleus of an animal cell. Biolistics – In this cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA
Question 21.
Genetically Modified Organism (GMO) is always a debatable topic among scientists,’academicians and public. State any four usefulness of GMOs. (MARCH-2015)
Answer:
i) More tolerant to abiotic stresses (cold, drought, salt, heat).
ii) Reduced reliance on chemical pesticides (pest- resistant crops).
iii) Helped to reduce post harvest losses.
iv) Increased efficiency of mineral usage by plants
v) Enhanced nutritional value of food, e.g., Vitamin ‘A’enriched rice.
Question 22.
Biotechnology in agriculture will lead to pest resistant plants, which could decrease the amount of pesticides used. For example Bt cotton. Expand the letter ‘B’ and ‘t’. (MARCH-2015)
Answer:
B-Bacillus t-thuringiensis
Question 23.
In 1997, an American company got patent rights on Basmati rice through the U.S. Patent and Trademark Office. Variety of Basmati had actually been derived from Indian farmer’s varieties. If so, what is Biopiracy? (MARCH-2015)
Answer:
It is the use of bio-resources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensatory payment.
Question 24.
One of the speaker in the National Children’s Science Congress delivered a talk about Transgenic animals. Explore any 2 benefits of Transgenic animals. (MAY-2015)
Answer:
i) Study of disease: Transgenic animals can be used to know, how genes contribute to the development of disease.
ii) Biological products: Transgenic animals that produce useful biological products. In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk contained the human alpha- lactalbumin. It is nutritionally a more balanced product for human babies than natural cow-milk.
Question 25.
The recombinant DNA technological process have made immense impact in the area of healthcare. How Eli Lilly produced Insulin? (MARCH-2016)
Answer:
Eli lily prepared two DNA sequences corresponding to A and B chains by using recombinant DNA technology , it is introduced into plasmid of E coli and produced polypeptide chains A and B.
These chains are separated and connected by using disulphide linkage to form human insulin
Question 26.
A farmer approached an Agriculture officer to tell his grievance i.e.. reduction in tobacco yield due to root damage by nematodes, (MARCH-2016)
a) What is your suggestion to prevent this infestation?
b) Briefly explain the process.
Answer:
a) RNA interference (RNAi)
b) The best method used to prevent the attack of nematode is RNA interference (RNAi). It involves silencing of a specific mRNA of nematode. Here the complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing).
Question 27.
RNA can suppress the activity of a gene. Explain it with suitable example. (MAY-2016)
Answer:
In this process nematode specific genes were introduced into the host plant through agrobacterium,it produce both sense and antisense RNA, since this two RNAs are complementary to each other, form a dsRNA RNAi is operated and the nematode can’t produce proteins.
Question 28.
Match the following: (MARCH-2017)
Answer:
Question 29.
Insulin getting assembled into a mature form was the major challenge in commercial insulin production by rDNA technology. How did Eli Nilly found a solution to this problem? (MARCH-2017)
Answer:
An American company Eli Lilly in 1983 prepared two DNA sequences corresponding to A and B, chains of human insulin and inserted 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.
Question 30.
A) Bt cotton is an example of genetically engineered cotton. (MAY-2017)
a) What does Bt stands for?
b) Name the gene responsible for Bt toxin production.
c) How does the toxin kill the insect?
OR
B) Gene therapy is a corrective therapy for a hereditary disease.
a) Name the disease which was successfully corrected by gene therapy for the first time.
b) How gene therapy is practiced for a permanent cure of the disease?
Answer:
A) a) Bacillus thuringiensis
b) Cry gene
c) Bt toxin protein exist as inactive protoxins it is converted into an active form in the presence of the alkaline pH of insect gut. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and results in the death of insect.
OR
B) a) Adenosine deaminase deficiency (ADA)
b) In this, functional ADA cDNA is introduced into embryonic stage. It is permanent cure forthe disease.
Question 31.
Antigen – antibody reaction is the basis of the technique called ____. (MAY-2017)
a) ELISA
b) PCR
c) RNA interference
d) Gene therapy
Answer:
ELISA