Biotechnology and its Application Question Answers: NCERT Class 12 Biology

Green revolution or third Agricultural Revolution is the research technology transfer initiatives which increases agricultural production by adopting modern methods and technologies. There are some key elements that includes: adoption of new technology like High- yielding varieties, limited water supply by using irrigation, using high yielding variety of seeds, chemical fertilizers etc. Some limitations of green revolution are as follows:

1. Continuous use of groundwater for the irrigation, reduces the water level.
2. Chemical fertilizers are when used in excess amount, leads to the loss of soil fertility. And when the rain comes or when the water from the agricultural field with the excess amount of chemical fertilizers comes in the water, it gradually pollutes the water and leads to eutrophication in aquatic organism and biomagnification in terrestrial organisms.
3. Excess amount of water supply may lead to water logging and excess amount of salt concentration in water causes salinization which are the problems that came across the green revolution.     

The patent on Basmati should not have gone to an American company and following are the reasons:

1. This patent could have prevented Indian people from growing Basmati rice and this patent crop is claimed by an American company that was derived by the crossing Indian rice variety.
2. There are several Basmati varieties have been grown in India (almost 27 varieties), so that is an integral part of traditional farm practices in India.   

Insulin is used to cure the diabetic patients. Insulin is obtained from the pancreas of cattle and pigs which is little bit differ from the human insulin by their amino acid sequences. And by some slight changes in the polypeptide chain leads to some allergic reactions in the human beings.

On the other hand, Insulin is a polypeptide hormone and is composed of 51 amino acids arranged in two chains that are linked together by two disulfide bridges. It is produced by the β- cells of the islets of Langerhans and it favors the synthesis of glycogen, triacylglycerols and proteins. This acts to reduce the glucose concentration in the blood and thus stimulates the conversion of glucose to fats, proteins, ribulose 5- phosphate and glycogen etc.

Genetic manipulation of animal cells or animals that have been permanently engineered by the gene insertion are known as transgenic animals and these contains functional foreign genes that have been introduced into the genome by genetic engineering. These transgenic are designed to increase study of how genes contribute to development of diseases and these are made to serve as the models for the human diseases like cancer, cystic fibrosis, Alzheimer etc. so that preventive measures are taken. For example: Transgenic Goats, they have human gene which codes for blood clot dissolving protein, i.e. Tissue plasminogen activator (TPA) is formed, secreted in milk. And, this is used for the treatment of coronary thrombosis disease. 

Animals that have been permanently engineered by the gene insertion are known as transgenic animals and the foreign genes are added are known as transgenes. In 1981, Ralph Brinster and Richard Palmiter introduced first transgenic animal, by introducing a gene for rat growth hormone (GH) into fertilized eggs of mice.

First transgenic cow name was Rosie and is considered as different from normal cow. Transgenic cow that contains cDNA which codes for the antibacterial human iron- binding protein called lactoferrin have been produced. In this cow, human genes are transferred that are expressed in mammary tissues and then the milk contains nutritionally more balanced product, α- lactalbumin for human bodies than natural cow milk.

PCR (polymerase chain reaction) is used to amplify the nucleic acid (single copy of DNA into multiple) without using cells. Very low concentration of pathogens (bacteria, viruses) in the human body can be detected by amplification of their nucleic acid by using the technique PCR. When the source of DNA is impure, can be amplified by PCR technique. And when the sequence of HIV DNA is known, PCR method will help in the detection of HIV DNA in the blood or the tissues in suspected AIDS patients and to detect mutations in suspected cancer patients. 

GEAC stands for Genetic Engineering Approval Committee, functions in or set up by the Ministry of environment, forest and climate change (MoEF&CC) to regulate research, testing or commercial release of genetically modified crops, foods and organisms. There are several objectives of GEAC:

1. That is to permit the use of Genetically Modified organisms and their products for commercial applications, for the release of transgenic crops in the environment etc.
2. To adopt procedures for restrictions, production, scale, import, export and applications of Genetically Modified Organisms.
3. To authorize agencies to have the large scale production.

This committee gave approval for cultivation of Bt Cotton, the only commercially grown GM crop in India, in 2002.     

The patent was filed for the Basmati variety of Indian rice. Basmati is a variety of long grained aromatic rice which have been traditionally grown in India and this variety of rice have been cultivated in Indian subcontinents (have been cultivated all over the world) for the centuries. A USA Company has acquired the patent to claim the new variety of the Basmati rice.  

Genetically Modified Organisms (plants, bacteria, fungi and animals) are ones that has its genetic material altered through any method (manipulation), including conventional breeding (development of new varieties of plants by using natural processes or older tools). They are usually formed by the alteration in gene is introduced in the organism and carried out in the in vitro condition. There are several advantages of genetically modified organisms and these are as follows:

1. There are genetically engineered crops that are intrinsically resistant to insects like Bt (Bacillus thuringiensis) cotton.
2. Several approaches have been used to modify the plants for the resistance of viruses like introduction of coat protein gene, antisense RNA approach etc. There are some transgenic plants that contains virus coat proteins which linked to strong promoter have produced in several crops like tobacco, tomato, potato etc.
3. Many crops have been engineered for the resistance of herbicides like glyphosate.
4. It enhances the value of food like gives more nutritious or tastier food which is very important to our health by the less use of pesticides like golden rice.

GMO refers to the Genetically Modified Organisms which are also known as transgenic organisms. The organisms which contain functional foreign molecules and then introduced into their genome by recombinant DNA technology from another species or animals that have permanently engineered by the gene insertion are known as transgenic organisms. But GMO are little bit different from transgenic organisms; as GMO are ones that has its genetic material altered through any method or transgenic are those which are genetically engineered through using foreign gene.

GMO are different from hybrids. Hybrids are formed by crossing two different genome of species or strains whereas GMO are usually formed by the alteration in gene is introduced in the organism and carried out in the in vitro condition.

Diagnostic involves the detection of diseases. Biotechnology has developed several diagnostic test in the clinical use today. Many of these tests are able to diagnose conditions only by taking blood sample or mouth swab. For example: ELISA (Enzyme- linked Immuno sorbent Assay) used for the detection of HIV; this test involves the linkage of label enzymes to either antigens or antibody and their reaction is measured using colorimetric signals, Hepatitis B and C. On the other hand, therapeutics helps in the treatment for the particular type of diseases. For example: Antibiotic resistant gene (Antibiotic resistance gene are mostly used as selectable markers and as well as antibiotics. A host cell strain is chosen which will react to the particular antibiotics, which are been used in transformation process) like Ampicillin, is an antibiotic which helps in the treatment of bacterial infection in humans by inhibiting the cell wall synthesis by disrupting peptidoglycan cross- linking.     

ELISA stands for Enzyme- linked Immuno sorbent Assay and this exploits an enzymatic reaction for detecting the immune reaction. Many enzymes are used for ELISA like alkaline phosphatase, urease, beta galactosidase and horseradish peroxidase. ELISA can be used qualitatively to detect the presence of antigens (detect infection by pathogen) and antibodies (are synthesized against the pathogen or bacteria for the defense). This test involves the linkage of label enzymes to either antigens or antibody and their reaction is measured using colorimetric signals.

Principle of this test involves the competitive binding of antigen and specific enzyme to the specific antibody. ELISA is used for the detection of disease AIDS or HIV.

DNA technology helps in to identify the individuals with genetic disorders before the appearance of symptoms. All diseases involves the changes in gene expression in the affected cell. Presence of pathogens are suspected when they are in high concentration, which produced disease symptom but when they are in low concentration, this can be detected by amplification of their nucleic acid by the PCR. Like in the PCR (polymerase chain reaction) is used to amplify the nucleic acid (single copy of DNA into multiple) without using cells. When the source of DNA is impure, can be amplified by PCR technique. And when the sequence of HIV DNA is known, PCR will help in the detection of HIV DNA in the blood or the tissues.  

Biopiracy is the robbery of biological or genetic resources indigenous to the country and these resources have many uses in agriculture, health care and chemical industries. This process involves collection of biological resources sample, which are unnoticed. Then they are subjected to product development for the commercial scale use. Or we can say that Biopiracy is the term refers to the use of bio- resources by multinational companies without proper authorization or right, without compensatory payment.

Some MNCs make minor tweaking for obtaining the patent on products or processes which have been under the domain of traditional knowledge of different countries. By getting patent, companies get license to exploit their resources worldwide. And this traditional knowledge can be exploit to develop modern applications which is used to save time, efforts and expenditure too. Some recent patents granted by U.S. and Trademarks Office to American companies on turmeric, neem and basmati rice. 

Development of insecticidal resistance is the application of transgenic plants. By the Recombinant DNA technology, it is possible to develop crops which are intrinsically resistant to insects. When the toxins are present in inactive form, the organisms which produces these toxins, does not harm anymore. This mechanism is useful for micro-organisms because they become active by certain metabolic and biochemical changes like pH or temperature. For example: in Bt (Bacillus thuringiensis) toxin, insecticidal proteins called cry proteins, when get accumulated in the bacterium as an inactive state and after ingestion by the insect, in alkaline pH of gut, this protoxin cleaved by protease, results in the shorter version of proteins and shows toxicity/ acidity, by binding inside of the insect’s gut and damages the surface epithelium. Thus, these toxins resist the proteins and by the action of host, these micro- organisms does not get killed.    

While creating genetically modified organisms genetic barriers are not respected because genetic barriers leads to mutation and then due to this unwanted organisms are produced  which affects the food chain of the other organism in the environment. When these GMO introduced into the ecosystem, it can have dire (very serious or urgent) consequences for the ecosystem. Thus, when genetic barriers are not respected it can have long term effect.      

The Indian parliament has cleared the second amendment of the country’s patent bill because it prevents the overexploitation of the bio- resources (essential components related to economic activities of the Nation) and the use of ancient Indian knowledge and techniques by other countries. Some multinational companies obtain patent on products or services which had been the part of the ancient knowledge. This amendment had the potential of exploitation of indigenous people by commercial exploitation. So, this amendment has to be cleared out.    

toxin is inactive:

In bacteria, the toxin is present in an inactive form, called prototoxin, which gets converted into active form when it enters the body of an insect.

Orally active protein pharmaceuticals contain biologically active materials such as peptides or proteins, antibodies, and polymeric beads. It is administrated orally into the body through various formulations. It involves the encapsulation of protein or peptide in liposomes or formulations using penetration enhancers. These proteins or peptides are used for treatment of various diseases and are also used as vaccines. However, the oral administration of these peptides or proteins has some problems related to it. Once these proteins are ingested, the proteases present in the stomach juices denature the protein. As a result, their effect will be nullified. Hence, it is necessary to protect the therapeutic protein from digestive enzymes, if taken orally. This is the reason for the proteins to be injected directly into the target site.How to make:

Transgenic bacteria contain foreign gene that is intentionally introduced into its genome. They are manipulated to express the desirable gene for the production of various commercially important products.

An example of transgenic bacteria is E.coli. In the plasmid of E.coli, the two DNA sequences corresponding to A and B chain of human insulin are inserted, so as to produce the respective human insulin chains. Hence, after the insertion of insulin gene into the bacterium, it becomes transgenic and starts producing chains of human insulin. Later on, these chains are extracted from E.coli and combined to form human insulin.

The production of genetically modified (GM) or transgenic plants has several advantages.

(i) Most of the GM crops have been developed for pest resistance, which increases the crop productivity and therefore, reduces the reliance on chemical pesticides.

(ii) Many varieties of GM food crops have been developed, which have enhanced nutritional quality. For example, golden rice is a transgenic variety in rice, which is rich in vitamin A.

(iii) These plants prevent the loss of fertility of soil by increasing the efficiency of mineral usage.

(iv) They are highly tolerant to unfavourable abiotic conditions.

(v) The use of GM crops decreases the post harvesting loss of crops.

However, there are certain controversies regarding the use of genetically modified crops around the world. The use of these crops can affect the native biodiversity in an area. For example, the use of Bt toxin to decrease the amount of pesticide is posing a threat for beneficial insect pollinators such as honey bee. If the gene expressed for Bt toxin gets expressed in the pollen, then the honey bee might be affected. As a result, the process of pollination by honey bees would be affected. Also, genetically modified crops are affecting human health. They supply allergens and certain antibiotic resistance markers in the body. Also, they can cause genetic pollution in the wild relatives of the crop plants. Hence, it is affecting our natural environment.

Cry proteins are encoded by cry genes. These proteins are toxins, which are produced by Bacillus thuringiensis bacteria. This bacterium contains these proteins in their inactive from. When the inactive toxin protein is ingested by the insect, it gets activated by the alkaline pH of the gut. This results in the lysis of epithelial cell and eventually the death of the insect. Therefore, man has exploited this protein to develop certain transgenic crops with insect resistance such as Bt cotton, Bt corn, etc.

Gene therapy is a technique for correcting a defective gene through gene manipulation. It involves the delivery of a normal gene into the individual to replace the defective gene, for example, the introduction of gene for adenosine deaminase (ADA) in ADA deficient individual. The adenosine deaminase enzyme is important for the normal functioning of the immune system. The individual suffering from this disorder can be cured by transplantation of bone marrow cells. The first step involves the extraction of lymphocyte from the patient’s bone marrow. Then, a functional gene for ADA is introduced into lymphocytes with the help of retrovirus. These treated lymphocytes containing ADA gene are then introduced into the patient’s bone marrow. Thus, the gene gets activated producing functional T- lymphocytes and activating the patient’s immune system.

DNA cloning is a method of producing multiple identical copies of specific template DNA. It involves the use of a vector to carry the specific foreign DNA fragment into the host cell. The mechanism of cloning and transfer of gene for growth hormone intoE.coli is represented below.

Recombinant DNA technology (rDNA) is a technique used for manipulating the genetic material of an organism to obtain the desired result. For example, this technology is used for removing oil from seeds. The constituents of oil are glycerol and fatty acids. Using rDNA, one can obtain oilless seeds by preventing the synthesis of either glycerol or fatty acids. This is done by removing the specific gene responsible for the synthesis.

Golden rice is a genetically modified variety of rice, Oryza sativa,which has been developedas a fortified food for areas where there is a shortage of dietary vitamin A. It contains a precursor of pro-vitamin A, called beta-carotene, which has been introduced into the rice through genetic engineering. The rice plant naturally produces beta-carotene pigment in its leaves. However, it is absent in the endosperm of the seed. This is because beta-carotene pigment helps in the process of photosynthesis while photosynthesis does not occur in endosperm. Since beta-carotene is a precursor of pro-vitamin A, it is introduced into the rice variety to fulfill the shortage of dietary vitamin A. It is simple and a less expensive alternative to vitamin supplements. However, this variety of rice has faced a significant opposition from environment activists. Therefore, they are still not available in market for human consumption.

No, human blood does not include the enzymes, nucleases and proteases. In human beings, blood serum contains different types of protease inhibitors, which protect the blood proteins from being broken down by the action of proteases. The enzyme, nucleases, catalyses the hydrolysis of nucleic acids that is absent in blood.