FST -1

17th Part

Q.  What is Biotechnology? Describe the underlying techniques of genetic engineering and enzyme immobilization.               

A. Biotechnology is the industrial utilization of biological systems or processes. The most ancient biotechnological art is fermentation. Living micro-organisms have been used for centuries to make curds. condiments, cheese, and vinegar, to prepare dough for bread. The ability to control and manipulate microbes and use them for various applications has resulted in current biotechnology where microbes are used for a variety of purposes, related to health, medicine. food, pollution control, etc.

Genetic Engineering

The modem biotechnology revolution is based on the understanding and manipulation of the structure of DNA. DNA is a complex organic molecule that directs the synthesis of proteins in all living organisms. Thus, it controls the physical structure, growth, reproduction, and function of all living beings. The program for controlling protein synthesis is coded in the chemical structure of DNA. The discovery of the code and the synthesis of DNA in test tubes were important milestones in genetic engineering. However, the foundation of genetic engineering was laid by the discovery, that DNA supplied from outside is accepted by micro-organisms. DNA thus inserted into the cell en from a micro-organism, enables the cells to make the proteins specified in the codes of the inserted DNA. These new cells can be cultivated or cloned, until a significant number of cells are available to produce specific, desired protein molecules. Through genetic engineering, large quantities of scarce biologically significant proteins that are not easily available from natural sources can be manufactured. For example, insulin needed by diabetic patients can now be produced on a large scale using this technique. By selecting suitable bacteria, and using genetic engineering techniques, new varieties of bacteria that can eat man-made artificial products like plastics are being developed.

Enzyme Immobilisation

The use of enzymes as catalysts is well known in a number of industries, such as baking or wine making. But purified enzymes are soluble in water. It is, therefore, not easy to remove them from the final product. Further, it is difficult to re-use them. Thus, enzyme activity is lost in one cycle of the chemical reaction. These difficulties led to the development in the late 1960s of immobilized enzymes. The trick is to link an enzyme chemically to a large molecule, such as gelatin. It can then be used as a catalyst, and it can be extracted with the large molecule, for use once again. Immobilized enzymes have been successfully used in the production of semi-synthetic penicillin and in the large scale production of fructose from maize. Fructose is sweeter than glucose, yet it has the same calorific value and is used as a low-calorie sweetener.

Q.  Fibre optics technology              

A. Fiber optics is the technique of transmitting light waves through glass wires which as thin as human hair. These wires called optical fibers could be made of glass or transparent plastic, quartz, nylon or polystyrene. Optical fibers are thin hair-like solid strands that carry light along their length, by a process of multiple total internal reflections.

Applications of Optical Fibres

Fiber optics finds many applications in areas like medicine and communications.

Medicine

Instruments made of optical fibers, called endoscopes, are used to see the internal organs of the human body, such as the interior of the stomach, or the bronchial tubes. Once inserted into the body, some fibers of the bundle carry light so that the internal organ is lit up. Other fibres are used to return light so that the image of the interior is carried to the observer outside. Endoscopes are often connected to a camera or TV monitor. The images are very useful in heart and brain surgery and a diagnosis of some other diseases.

Telecommunication

The use of optical fibers has been very advantageous in telecommunications. Signals of voice, text, computer data or picture transmissions are superimposed on laser beams. The modulated laser beams are then guided along optical fibers, to various points where they are received. At the receiving end, one is able to hear the voice, read the data or see the picture. The signal carrying capacity of light waves(lasers) is much greater than that of radio waves or waves along copper wires. Therefore, the light waves traveling in fibers can carry thousands of different signals. For instance, a pair of glass fibers can carry 1300 telephone calls at the same time, as against 24 for copper wires.

Q.   (a) What is technology forecasting? Why is it an important area of study today?                                     

A.  Technology forecasting is a process to predict the relevant technologies of the future to satisfy the social need from the point of general planning. Also, future technologies are of interest to private manufacturers because their profits would depend on it. Technology forecasting is a cumbersome process. The path from science to technology and then to make useful devices and goods in society is not straight forward. Scientific discoveries sometimes took several decades before society made use of them as to produce devices based on them and add to general technology and science. 

         Successful technological forecasting is important to invest scarce funds to emerging technologies. Technological Forecasting appears to play an important role in the economic development of the country. Based on this importance, technological forecasting has often been used to support policy-making decisions. For technology forecasting, one has to keep an eye on the various areas of scientific research, as well as on social and economic aspects-not only in one country, but in the world at large. And one who is effectively able to do so stands to gain tremendously. More scientific research and technological development can be directed so as to obtain highly useful products.

            Technological forecasting is an important area of study today because of the resources to be allocated for making the actual products, the time taken to manufacture goods and if these products are required. There is scientific research in various branches; some of it is abstract or theoretical, some of the research is applied to produce practical products. Another important factor is to know if the society is ready to utilize the product, is it possible to create demand in the market to make a profit (or it must be created by advertising), before the likely product becomes an actually available technology.

Q.  Semiconductors              

Q.  n-type and p-type semiconductors. 

A. A semiconductor is a material whose ability to conduct electric current is greater than that of an insulator but less than that of metals. Silicon and germanium are the most commonly used semiconductors. Some other compounds like gallium, arsenide, indium, antimonide are-also used. The ability of semiconductors to conduct electricity depends critically upon their purity, or rather their impurity. A pure crystal of silicon or germanium acts more or less as an insulator. However, if an impurity is added to the crystal it becomes more conductive. Semiconductors are the basis of all the sophisticated electronics gadgets we have today. Digital watches, calculators, aircraft, spacecraft, satellites, telephone exchanges, lasers, and many more devices have components or equipment made up of semiconductors. 

     The ability of semiconductors to conduct electricity depends critically upon their purity, or rather their impurity. A pure crystal of silicon or germanium acts more or less as an insulator. However, if an impurity is added to the crystal it becomes more conductive. By the way, "impurity" does not mean a 50-50 mixture or even one part of impurity in ten parts of silicon. In useful semiconductors, a ton of silicon may have I mg of the element arsenic. Even the tiny bit of arsenic contributes surplus electrons to silicon, which then becomes a better conductor. Such a piece of silicon would be called an n-type semiconductor. On the other hand, a like amount of boron would cause a different kind of conduction to take place and the piece of silicon so treated would be called p-type semiconductor. The word 'doping' is used by scientists to describe the introduction of such small impurities.

Q.  What do you understand by nuclear fission ? Give any one of its applications. 

A. Nuclear fission is the splitting of a large nucleus of Uranium 235 into two smaller nuclei. If neutrons were shot at the nuclei of Uranium 235, the nuclei split into two and produced other neutrons along with huge energy to repeat the process and form a chain reaction. This is called nuclear fission.

         When the atom splits, the masses of the fragments and the neutrons produced do not add up to the mass of the original. A tiny amount of matter disappears. This lost matter turns into energy. The amount of energy 'E' generated by the lost matter of mass 'm' is given by -

                    E = mc2, where c is the speed of light.

c is large (about 300 million metres/sec) and c2 is enormous (about 90,000 trillion m2/sec2).

Thus, a small amount of lost matter would get converted into very very large amounts of energy.

Chain Reaction

When the atomic nucleus splits, it not only gives off energy but also throws out two or three more neutrons. 'These new neutrons can, in turn, split two or three other atoms. This way they release more energy and more neutrons, which will split more atoms. Once the splitting of the nuclei starts, it becomes self-sustaining. This whole process is called a chain reaction. Nuclear fission can be maintained as a controlled chain reaction in a nuclear reactor to produce energy which is used to heat water producing steam thus running the blades of the turbine to produce electricity.

Q.  Name two areas where we do not depend on imported technology.   

A. Energy sector and Chemicals.

Energy - the energy sources available in India are fossil fuels (like lignite, coal, and petroleum) the sun, wind, geothermal energy (for example, hot springs) and water (hydro-electric power). These energy sources are used by indigenous technology to produce electricity. The cost of energy varies. The cost of energy is also quite low in the case of fossil fuels. Large deposits of lignite have been found in Tamil Nadu. But it costs more than coal. Apart from fossil fuels, nuclear energy is considered to be one of the proven alternative energy sources and is developed to produce electricity. In India, at present, fossil fuels. hydro-electric power, biomass conversion. and nuclear power are the ones that are being used.

Chemicals -  We have a sizeable glass and ceramic industry, surface coating industry, food, and food by-product industry. Our agrochemical industries have developed indigenous technology for the manufacture of pesticides and insecticides. We also produce caustic soda, chlorine, cement, carbon, urea, nitric acid, super phosphates and gases like hydrogen, oxygen, and nitrogen. Our soap and detergent industry indigenously manufactures soap, detergents and glycerine. Our oils and fats industries manufacture vegetables and animal oils and fats. A major breakthrough has been achieved in the field of petrochemicals. We have a number of petroleum processing plants and petrochemical industries, the biggest being in Baroda. India produces two-thirds of her petroleum requirements.