Gujarat Board GSEB Textbook Solutions Class 12 Biology Chapter 12 Biotechnology and Its Applications Textbook Questions and Answers, Additional Important Questions, Notes Pdf.
Gujarat Board Textbook Solutions Class 12 Biology Chapter 12 Biotechnology and Its Applications
GSEB Class 12 Biology Biotechnology and Its Applications Text Book Questions and Answers
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.
The Bt toxin protein exists as inactive protoxins but once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals.
What are transgenic bacteria? Illustrate using any one example.
Transgenic bacteria are microbes carrying clones of foreign genes. It is also known as genetically modified bacteria.
These bacteria are being employed for many functions.
(a) Two DNA sequences (coding for A and B chains of human insulin) were introduced into the plasmid of bacteria E. Coli. This transgenic bacteria produced insulin chain- Used as biochemical factories
(b) Microbes have been genetically changed to help in cleaning the polluted environment, eg:- Pseudomonas putida for cleaning oil spills pseudomonas species for removing heavy metal pollutants. Aceto bacter aerogans for the decomposition of DDT and Flavobacterium for the decomposition of 2,4-D.
Compare and contrast the advantages and disadvantages of the production of genetically modified crops.
- Increased yield
- Minimum use of pesticides
- Minimum use of fertilizer-resistant plants.
- Developing disease-resistant and stress-tolerant plants
- Developing nutritional enhancement in plants
- Gene flow will result in cross-pollination with wild relatives
- Genetically modified crops may evolve toxic metabolites due to recombination.
- Affect the livelihood of farmers of third world countries.
What are Cry proteins? Name an organism that produces it. How has man exploited this protein to his benefit?
Cry proteins are crystalline proteins produced by Bacillus thuringiensis. They are also known as Bt toxins. The toxin is coded by a gene named cry. There are a number of them, for example, the proteins encoded by the genes crylAc and cryllAb control the cotton bollworms, that of crylAb controls corn borer. Cry proteins are made to express in crop plants like cotton to develop transgenic Bt-cotton plants.
What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
Gene therapy is a collection of methods that allows correction of a gene defect that has been diagnosed in a child/embryo. Here genes are inserted into a person’s cells and tissues to treat a disease. Correction of a genetic defect involves the delivery of a normal gene into the individual or embryo to take over the function of and compensate for the non-functional gene.
Adenosine deaminase (ADA) enzyme is crucial for the immune system to function. The disorder is caused due to the deletion of the gene for adenosine deaminase. In some children ADA deficiency can be cured by bone marrow transplantation; in others, it can be treated by enzyme replacement therapy, in which functional ADA is given to the patient by injection. But the problem with both of these approaches is that they are not completely curative. As a first step towards gene therapy, lymphocytes from the blood of the patient are grown in a culture outside the body. A functional ADA cDNA (using a retroviral vector) is then introduced into these lymphocytes, which are subsequently returned to the patient.
Diagrammatically represent the experimental steps in cloning and expressing a human gene (say the gene for growth hormone) into a bacterium like E. coli?
Isolate gene for growth hormone
Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and the chemistry of oil?
It is the nature of fatty acids that determines the uniqueness of the oil in each plant. Most of the oils contain one mole of glycerol and 3 moles of fatty acids. Based on the nature of the plant oils we can construct recombinant bacteria that can synthesize these oils, and extract from them.
Find out from the internet what is golden rice.
Golden rice is genetically engineered rice with high vitamin A content.
Does our blood have proteases and nucleases?
Yes. They help in the formation of a blood clot.
Consult the internet and find out how to make orally active protein pharmaceuticals. What is the major problem to be encountered?
Orally active protein can be made through DNA technology, for instance, hirudin a blood-clotting protein has been produced in the seeds of Brassica napus. The transgenic cow named Rosie contains human protein a-lactalbumin. However such proteins may cause allergic reactions in some people.
GSEB Class 12 Biology Biotechnology and Its Applications Additional Important Questions and Answers
Expand the following short forms related to biotechnology,
a. double-stranded Ribo Nucleic Acid
b. Ribo Nucleic Acid interference
c. Bacillus thuringiensis
d. Genetically Modified Organisms
e. Adenosine deaminase
f. Polymerase Chain Reaction
g. Enzyme Linked Immune Sorbant Assay
h. Genetic Engineering Approval Committee
What is the significance of the process of RNA inference (RNAi) in eukaryotic organisms? (CBSE 2008)
It is a method of cellular defense in eukaryotic organisms, which involves silencing of m.RNA.
The name of the gene which encodes for the toxin called crystal protein in Bacillus thuringiensis is ‘cry’. What are the different types of ‘cry’ genes and name the type of insects controlled by each type?
Cry IAc, Cry IIAb and Cry IAb
Cry I Ac and Cry IIAb control cotton bollworms
Cry IAb controls corn borer.
What was the specialty of the milk produced by the transgenic cow, Rosie? (AI 2008)
The milk contained human protein alpha-lactalbumin (2.4gm/liter) which is nutritionally important for human babies.
Name the nematode which injects the roots of tobacco plants and was treated with the help of RNA interference.
Give a reason for each of the following.
- Insulin cannot be administered orally to diabetic patients.
- Biopiracy affects India the most.
- Insulin is a polypeptide and can be digested by peptidase in the alimentary canal. Hence it cannot be administered orally.
- India is rich in biodiversity and traditional knowledge related to the use of bio-resources than many other countries, hence it is affected the most with biopiracy.
Bt toxin seen inside Bt cotton exists in an inactive form. But when a pest feeds on Bt cotton, it dies. How does the toxin in the cotton plants kill the pest?
When the insect pest ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilises the toxin crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores, which causes cell swelling and lysis and eventually death of the insect.
Mention the uses of cloned genes in, molecular diagnostics.
- Cloned genes are used as probes to detect the presence of its complementary DNA strand; the muted gene will not hybridize with the probe and hence will not appear in the photographic film.
- When cloned genes express themselves and produce recombinant proteins, they help in developing sensitive diagnostic techniques.
In tobacco plants, a nematode Meloidogyne incognita infects the roots of tobacco plants and causes a great reduction in yield. To prevent this nematode infection a new method was introduced called RNA interference (silencing of specific mRNA). Briefly explain this method done in tobacco plants using Agrobacterium vectors.
The nematode-specific genes were introduced into the host plant using Agrobacterium vectors. The introduction of DNA was such that it produced both sense and anti-sense RNA in the host cells. These two RNAs together form double-stranded RNA that initiated RNAi (RNA interference) which silenced the specific mRNA of the nematode. Thus parasite could not survive in the host.
The development of biotechnology has made an immense impact in the area of health care. Briefly explain any three such developments with examples.
i. Genetically engineered insulin: First two DNA sequences corresponding to A and B, chains of human insulin and introduced them 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.
ii. Gene therapy: Gene therapy is a collection of methods that allows correction of a gene defect. In ADA deficiency treatment, lymphocytes from the blood of the patients are grown in a culture outside the body. A functional ADA cDNA is then introduced into these lymphocytes, which are subsequently returned to the patients.
iii. Molecular diagnosis: A very low concentration of a bacteria or virus can be detected by amplification of their nucleic acid by PCR. It is now routinely used to detect mutations in genes in suspected cancer patients and to detect HIV in suspected AIDS patients.
ELISA test is done to detect HIV in AIDS patients. What is the principle behind this test?
ELISA is based on the principle of antigen-antibody interaction. Infection by pathogen can be detected by the presence of antigen or by detecting the antibodies synthesised against the pathogen.
Transgenic animals are animals that have had their DNA manipulated to possess and express an extra gene. Comment on some of the areas where these transformed organisms are used.
a. To study the normal physiology and development: Transgenic animals can be specifically designed to allow the study of how genes are regulated and how they affect the normal functions of the body and its development.
b. Production of useful products: Transgenic animals that produce useful biological products can be created by the production of the portion of DNA which codes for a particular product.
c. Testing the safety of vaccines: Some transgenic organisms (mice) are being developed for use in testing the safety of vaccines before they are used by humans.
Transgenic organisms are used by humans in various fields, especially to test the action of vaccines before they are used in humans. According to your opinion is there any ethical issue in such experiments? Comment.
Yes, some ethical standards are required to evaluate the morality of all human activity that might help or harm living organisms. The manipulation of living organisms by the human race cannot go on any further without regulation.
Suppose a foreign company applies for patent for a medicine made from
turmeric. Turmeric is indigenously used in India as a medicine for skin diseases.
a. What is your opinion against such a theft of knowledge?
b. What do you call such an unauthorised use of bioresources?
a. It is our traditional knowledge and should be prevented from exploitation by others.
b. It is biopiracy
Genetic modification of organisms can have unpredictable results when such organisms are introduced into the ecosystem. Is there any regulatory authority in India to monitor such development of GM crops? Give a brief account.
Yes. GEAC – Genetic Engineering Approval Committee is an organisation set by the Indian government to make decisions regarding the validity of
GM research and the safety of introducing GM organisms for public services.
Define the term biopiracy. Explain the issue of Basmati rice patent in this context.
Biopiracy is the term used to refer the use of bio-resources by multinational companies and other organisation without proper authorisation from the countries and people concerned without compensatory payment.
Basmati rice are grown in India for centuries. An American company got patent rights on Basmati, proclaiming that they produced a new variety. But this new variety was actually produced from Indian farmer’s variety combined with some semi-dwarf varieties. The new patent gives the company the right to prevent other people from selling Basmati rice.
There are several arguments against Genetically Modified crops (G.M crops). Organisations like ‘Green Peace’ protest against the cultivation of G.M. crops. Suppose you are also a protestor, what will be your two main arguments against G.M. crops?
i. GM crops may cross fertilize with natural varieties producing undesirable characters.
ii. Since GM crops contain genes from other organisms like bacteria, these may produce toxic chemicals harmful to humans.
Biopiracy affects developing countries like India more than industrialized nations because our country is rich in …………………. and …………………. related to bio-resources.
(Bioetics/Biodiversity/Biopatent, Traditional resources/Traditional cultivation/Traditional knowledge)
Biodiversity and Traditional knowledge
Transgenic animals that produce useful biological products can be created by biotechnology. In 1997 the first transgenic cow was produced. Name the cow and the significance of its milk.
Rosie Milk produced by this transgenic cow contained the protein – human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow milk.
PCR is used to amplify desired DNA a billion times. It is also used in the molecular diagnosis of human disorders. Explain.
PCR is routinely used to detect HIV in suspected AIDS patients. It is used to detect mutations in genes in suspected cancer patients. It is a powerful technique to identify many other genetic disorders.
Name any three techniques related to biotechnology that help in the early diagnosis of some diseases.
- Recombinant DNA technology
- Polymerase Chain Reaction (PCR)
- Enzyme-Linked ImmunoSorbent Assay (ELISA)
Briefly explain the structure of human insulin. What was the main challenge for production of insulin using rDNA technique?
Insulin consists of two short polypeptide chains A and B, that are linked together by disulphide bridges.
Insulin is synthesised as a prohormone which contains an extra stretch called the C-peptide. This C peptide is not present in the mature insulin and is removed during maturation into insulin. The main challenge for production of insulin using recombinant DNA techniques was getting insulin assembled into a mature form.
List any four advantages of genetically modified crop plants over their wild domesticated relatives.
Advantages of genetically modified plants are,
- Make crops more tolerant to abiotic stresses. (Cold, drought, salt, heat)
- Reduce reliance on chemical pesticides. (Pest resistant crops)
- Help to reduce post-harvest losses.
- Increase the efficiency of mineral usage by plants.
- Enhance the nutritional value of food. e.g. Vitamin A enriched rice.
In the case of Bt cotton, how does the toxic insecticide protein produced by the bacterium kills the insect pest but not the cell of Bacillus thuringiensis where the toxic protein is generated?
Some strains of Bacillus thuringiensis produce proteins that kill certain insects as lepidopterans (tobacco budworm, armyworm). Bt forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein. But toxin does not kill the Bacillus. Because the Bt toxin protein exists as inactive protoxins but once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilizes the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis and eventually cause the death of the insect.
A multinational company (XYZ) marketed a medicine extracted from medicinal herbs grown in the sprawling fields in a foreign country. This herb is found only in our country and no compensation was paid or permission taken from relevant authorities.
i. What is the term used to refer to such an act committed by a multinational company?
ii. Justify the meaning of the term.
iii. What has our government done to prevent such deeds?
ii. Biopiracy is the use of bioresources by multinational companies and other organisations without proper authoritisation from the countries and people concerned without compensatory payment.
iii. The Indian Parliament has recently cleared the second amendment of the Indian Patent Bill, that takes such issues into consideration, including patent terms, emergency provisions, and research and development initiative.
How has biotechnology been applied in each of the following?
i. In curing diabetes mellitus
ii. In raising pest-resistant plants
iii. In producing more nutritionally balanced milk.
Do you think it is ethical to manipulate organisms for human benefits? Justify your answer.
i. Genetically engineered insulin is synthesised as a prohormone which contains an extra stretch called the C peptide. This C peptide is not present in the mature insulin and is removed during maturation into insulin. The production of insulin using rDNA techniques was getting insulin assembled into a mature form.
ii. Using Agrobacterium vectors, nematode-specific genes were introduced into the host plant. The introduction of DNA was such that it produced both sense and antisense RNA in the host cells. These two RNA’s being complementary to each other formed a double stranded (dsRNA). The consequence was that the parasite could not survive in a transgenic host expressing specific interfering RNA. The transgenic plant, therefore, got itself protected from the parasite.
iii. Medicines required to treat certain human diseases can contain biological products. Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA which codes for a particular product such as human protein (a -1 antitrypsin) used to treat emphysema. The first transgenic cow, Rosie, produced human protein-enriched milk. The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow milk.
The manipulation of living organisms by the human race cannot go on any further, without regulation. The biological significance of such things is also important. Genetic modification of organisms can have unpredictable results when some organisms are introduced into the ecosystem. The Indian government has set up organisation like GEAC to make decisions regarding the validity of GM research and the safety of introducing GM – organisms for public services. That makes use of the genetic material, plants and other biological resources that have long been identified, developed and used by farmers and indigenous people of a specific region/country.
You have developed a GM organism. Which government organization will you approach to obtain clearance for its mass production? Why is such a body necessary? Give two reasons.
The Indian government has set up the Genetic Engineering Approval Committee (GEAC) which will make decisions.
It is necessary for the following.
- This body is necessary to monitor the morality of all human activities that might help or harm the living organism.
- It will be responsible to make the decision regarding the validity of GM research and the safety of introducing GM organisms for public services.
(a) Write the disadvantages of human use of insulin from other animal sources
(b) What are the concerns about transgenic insulin?
- It causes allergy
- It causes other types of reaction
(b) Concerns about transgenic insulin
- The removal of C-peptide during maturation
- Assembling of the a and p polypeptides together to form a mature form of insulin.
What is somatic hybridization?
Somatic hybridization is the process of fusing protoplasts of a mature cell derived from two different varieties or species of plants in a suitable nutrient culture medium.