1. Rewrite the following statements using correct of the options and explain the completed statements.
(gluconic acid, coagulation, amino acid, acetic acid, clostridium, lactobacilli)
Ans.
(a) Process of Coagulation of milk proteins occurs due to lactic acid.
Explanation: The lactobacilli are the bacteria carrying out fermentation of the milk. In this process, the lactose sugar in the milk is converted into lactic acid. This lactic acid causes coagulation of the proteins present in the milk.
(b) Harmful bacteria in like Clostridium in the intestine are destroyed due to probiotics.
Explanation: In probiotics, there are lactobacilli which are useful. They control other bacteria present in the alimentary canal and also their metabolism. These bacteria thus stop the action of Clostridium which is a harmful bacteria.
(c) Chemically, vinegar is Acetic acid.
Explanation: Chemically vinegar is 4% acetic acid. It is a good preservative of the food and thus while using it as additive to the food, it is called vinegar.
(d) Salts which can be used as supplement of calcium and iron are obtained from Gluconic acid.
Explanation: The microbe Aspergillus niger is used on the source material of glucose and corn steep liquor to produce amino acid called Gluconic acid. Gluconic acid is used for the production of minerals used as supplement for calcium and iron.
2. Match the pairs.
‘A’ group ‘B’ group
a. Xylitol 1. Pigment
b. Citric acid 2. To impart sweetness
c. Lycopene 3. Microbial restrictor
d. Nycin 4. Protein binding emulsifier
5. To impart acidity
Ans. (a) Xylitoi – To impart sweetness (b) Citric acid – To impart acidity (c) Lycopene – Pigment (d) Nycin – Microbial restrictor.
3. Answer the following.
(a) Which fuels can be obtained by microbial processes? Why is it necessary to increase the use of such fuels?
Ans. (i) Microbial anaerobic decomposition of urban agricultural and industrial waste forms the gaseous fuel in the form of methane gas. (ii) Alcohol is another clean form of energy which is used in the form of ethanol.
The conventional fuels are exhaustible. After few hundred years, they will be over completely.
Moreover, these fossil fuels cause lot of air pollution due to emission of carbon dioxide. The fuels obtained by the microbial processes are not polluting. Therefore, it is necessary to increase the use of ecofriendly fuels.
(b) How can the oil spills of rivers and oceans be cleaned?
Ans. (i) Bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the ability to destroy the pyridines and other chemicals. (ii) Hence, these bacteria are used to clear the oil spills. (iii) These are called as hydrocarbonoclastic bacteria (HCB). (iv) HCB decompose the hydrocarbons and bring about the reaction of carbon with oxygen. CO2 and water is formed in the process.
(c) How can the soil polluted by acid rain be made fertile again?
Ans. (i) Sulphuric acid is present in the acid rain. (ii) Sulphuric acid is the source of energy for some
species of bacteria like Acidophillium spp. And Acidobacillus ferroxidens. (iii) Hence these bacteria can control the soil pollution occurring due to acid rain, and the soil can be made fertile again.
(d) Explain the importance of biopesticides in organic farming.
Ans. (i) Fluoroacetamide-like chemicals are mixed with soil due to use of chemical pesticides in agriculture. (ii) These prove to be harmful to other plants and animals as well as cause skin disease to humans. Therefore biopesticides are used nowadays. (iii) Bacterial and fungal toxins which can destroy pests and pathogens can be directly integrated into plants with the help of biotechnology. (iv) Being toxic to insects, plants are saved from them. (v) Spinosad, is a biopesticide. It is a by-product of fermentation.
(e) Which are the reasons for increasing the popularity of probiotic products?
Ans. (i) Probiotics are milk products containing active bacteria. (ii) These microbes maintain the balance of intestinal organisms. (iii) These products form the colonies of useful microbes in alimentary canal and control other microbes and their metabolic activities, improve resistance and lower the effects of harmful substances formed during metabolic activities. (iv) Useful microbes become inactive due to antibiotics, probiotics make them active again. (v) Nowadays probiotics are used for treatment of diarrhoea and treatment of poultry also.
(f) How the bread and other products produced using baker’s yeast are nutritious?
Ans. (i) Compressed yeast is used in commercial bakery industry. (ii) It is available in dry, granular form for domestic use. (iii) Yeast produced for commercial use contains various useful contents like carbohydrates, fats, proteins, various vitamins and minerals. (iv) Due to this, bread and other products produced with the help of yeast become nutritive.
(g) Which precautions are necessary for proper decomposition of domestic waste? (March ‘20)
Ans. (i) Segregation of waste – waste has to be segregated into dry and wet and accordingly headed for disposal. (ii) Dry wastes need to be sent for recycling. (iii) Wet wastes need to be sent to land-filling sites for composting.
(h) Why is it necessary to ban the use of plastic bags? (Sep ‘21)
Ans. (i) Plastic is a non-biodegradable substance. It cannot be degraded back into its original constituents. (ii) If burnt, it releases very toxic gases. (iii) If dumped in landfills it obstructs the other decomposition processes. (iv) Plastic bags pollute our land and water resources. (v) Plastic bags are harmful to wild life, marine and human health. Hence, plastic bags should be banned.
Ans.
5. Give scientific reasons.
(a) Use of mutant strains has been increased in industrial microbiology.
Ans. (i) Microbe’s rapid growth being non-toxic to humans, reduction in cultivation cost, production of additional enzymes, compounds to inhibit contaminant micro-organisms etc. has increased the use of mutant strains in industrial microbiology. (ii) Different types of antibiotics are also made by using processes of industrial microbiology. (iii) In pollution control and solid waste management, the industrial microbiology becomes helpful.
(b) Enzymes obtained by microbial process are mixed with detergents.
Ans. (i) Enzymes obtained by microbial process are active at low temperature, pH and pressure. (ii) Hence enzymes mixed with detergents help in process of dirt/muck removal even at low temperature.
(c) Microbial enzymes are used instead of chemical catalysts in chemical industry. (March ‘19)(Nov. ‘20)
Ans. (i) Microbial enzymes are active at low temperature, pH and pressure, due to which energy is saved and erosion – proof instruments are also not necessary. (ii) Enzymes carry out specific processes, hence unnecessary by-products are not formed due which expenses on purification are minimised. (iii) Elimination and decomposition of waste materials is avoided and enzymes can be reused. Such enzymes are eco-friendly. (iv) Therefore microbial enzymes are used instead of chemical catalysts in chemical industry.
6. Complete the following conceptual picture with respect to uses.
Complete the following conceptual picture related to environmental management. (March ‘20)
8. Answer the following.
(a) What is role of microbes in compost production?
Ans. (i) Microbes can bring about natural decomposition of the organic compounds. (ii) During the biodegradation, some bacteria and fungi bring about such decomposition and release the inorganic constituents back into the nature. (iii) Compost is formed in such a way by recycling process.
(b) What are the benefits of mixing ethanol with petrol and diesel?
Ans. (i) When petrol and diesel is mixed with ethanol, the proportion of CO2, CO, and hydrocarbons which are emitted in the atmosphere becomes lesser. (ii) The particulate pollutants which otherwise are emitted through combustion of petrol and diesel are not formed when fuels are mixed with ethanol. (iii) By adding ethanol to the fuels, the cost of expensive petrol or diesel also becomes less. (iv) The ethanol burns more efficiently hence ethanol is mixed with petrol and diesel.
(c) Which plants are cultivated to obtain the fuel?
Ans. (i) The ethanol is obtained from wheat, maize, beet, sugarcane and molasses of sugarcane. (ii) For biodiesel, the soybean, rapeseed, jatropa, mahua, flaxseed, mustard, sunflower, palm, jute and some types of algae are cultivated.
(d) Which fuels are obtained from biomass?
Ans. Fuels obtained from biomass:
(i) Solid fuels : Coal, dung, crop residue
(ii) Liquid fuels : Vegetable oils, alcohol
(iii) Gaseous fuels: Gobar gas, coal gas.
(e) How does the bread become spongy?
Ans. (i) Dough for bread is formed by mixing of baker’s yeast – Saccharomyces cerevisiae, water, salt and other necessary materials with flour. (ii) Due to fermentation of carbohydrates by yeast, sugar is converted into carbon-dioxide (CO2) and ethanol (C2H5OH). (iii) Dough rises up due to CO2 and the bread becomes spongy.