Textbook Solutions: Introduction to Microbiology | Science and Technology Class 10 (Maharashtra SSC Board) PDF Download

 Page 1


Introduction to Microbiology 
Exercise 
Q. 1. Rewrite the following statements using correct of the options and explain 
the completed statements. 
 
(gluconic acid, coagulation, amino acid, acetic acid, clostridium, lactobacilli) 
a. Process of -- -- -- -- of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like -- -- -- in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is -- -- --. 
d. Salts which can be used as supplement of calcium and iron are obtained from -
------ acid. 
Answer : a. Process of coagulation of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like clostridium in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is acetic acid. 
d. Salts which can be used as supplement of calcium and iron are obtained from 
gluconic acid. 
Q. 2. Match the pairs 
 
 
Answer : 
Page 2


Introduction to Microbiology 
Exercise 
Q. 1. Rewrite the following statements using correct of the options and explain 
the completed statements. 
 
(gluconic acid, coagulation, amino acid, acetic acid, clostridium, lactobacilli) 
a. Process of -- -- -- -- of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like -- -- -- in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is -- -- --. 
d. Salts which can be used as supplement of calcium and iron are obtained from -
------ acid. 
Answer : a. Process of coagulation of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like clostridium in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is acetic acid. 
d. Salts which can be used as supplement of calcium and iron are obtained from 
gluconic acid. 
Q. 2. Match the pairs 
 
 
Answer : 
 
Q. 3. A. Answer the following. 
 
Which fuels can be obtained by microbial processes? Why is it necessary to 
increase the use of such fuels? 
Answer : i. Gaseous fuel- methane can be obtained by microbial anaerobic 
decomposition of urban agricultural and industrial waste. 
ii. Ethanol, an alcohol is a clean (smokeless) fuel obtained during fermentation of 
molasses by the yeast- Saccharomyces. 
iii. Hydrogen gas is considered to be the fuel of future. Hydrogen gas is released during 
bio-photolysis of water in which bacteria perform the photo-reduction. 
It is necessary to increase the use of these fuels so that the fuels that are obtained from 
the non-renewable energy sources can be conserved. Also, air pollution can be 
reduced. 
Q. 3. B. Answer the following. 
 
How can the oil spills of rivers and oceans be cleaned? 
Answer : i. Spilling of petroleum oil occurs in ocean due to various reasons. 
ii. This oil may prove fatal and toxic to aquatic organisms. 
iii. It is not easy to remove the oil layer from surface of water by mechanical method. 
However, bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the 
ability to destroy the pyridines and other chemicals. 
iv. Hence, these bacteria are used to clear the oil spills. These are called as 
hydrocarbon clastic bacteria (HCB). HCB decompose the hydrocarbons and bring about 
the reaction of carbon with oxygen. CO2 and water is formed in this process. 
Page 3


Introduction to Microbiology 
Exercise 
Q. 1. Rewrite the following statements using correct of the options and explain 
the completed statements. 
 
(gluconic acid, coagulation, amino acid, acetic acid, clostridium, lactobacilli) 
a. Process of -- -- -- -- of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like -- -- -- in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is -- -- --. 
d. Salts which can be used as supplement of calcium and iron are obtained from -
------ acid. 
Answer : a. Process of coagulation of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like clostridium in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is acetic acid. 
d. Salts which can be used as supplement of calcium and iron are obtained from 
gluconic acid. 
Q. 2. Match the pairs 
 
 
Answer : 
 
Q. 3. A. Answer the following. 
 
Which fuels can be obtained by microbial processes? Why is it necessary to 
increase the use of such fuels? 
Answer : i. Gaseous fuel- methane can be obtained by microbial anaerobic 
decomposition of urban agricultural and industrial waste. 
ii. Ethanol, an alcohol is a clean (smokeless) fuel obtained during fermentation of 
molasses by the yeast- Saccharomyces. 
iii. Hydrogen gas is considered to be the fuel of future. Hydrogen gas is released during 
bio-photolysis of water in which bacteria perform the photo-reduction. 
It is necessary to increase the use of these fuels so that the fuels that are obtained from 
the non-renewable energy sources can be conserved. Also, air pollution can be 
reduced. 
Q. 3. B. Answer the following. 
 
How can the oil spills of rivers and oceans be cleaned? 
Answer : i. Spilling of petroleum oil occurs in ocean due to various reasons. 
ii. This oil may prove fatal and toxic to aquatic organisms. 
iii. It is not easy to remove the oil layer from surface of water by mechanical method. 
However, bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the 
ability to destroy the pyridines and other chemicals. 
iv. Hence, these bacteria are used to clear the oil spills. These are called as 
hydrocarbon clastic bacteria (HCB). HCB decompose the hydrocarbons and bring about 
the reaction of carbon with oxygen. CO2 and water is formed in this process. 
Q. 3. C. Answer the following. 
 
How can the soil polluted by acid rain be made fertile again? 
Answer : i. Sulphuric acid is present in the acid rain and materials coming out of mines. 
The erosion of metals present in statues, bridges and buildings occurs due to it. 
ii. Sulphuric acid is source of energy for some species of bacteria like Acidophillium 
spp. and Acidobacillus ferroxidens. Hence, these bacteria can control the soil pollution 
occurring due to acid rain. 
Q. 3. D. Answer the following. 
 
Explain the importance of biopesticides in organic farming. 
Answer : i. Some microbes-containing inoculants are produced by process of 
fermentation. These inoculants are sprayed on seeds before sowing and some of the 
inoculants are released into plants. 
ii. Solution containing Azotobacter and artificial nitrogenase is used in organic farming. 
iii. Soil pollution occurring due to chemical fertilizers is prevented due to use of these 
solutions. 
iv. Pesticides in the soil can be destroyed with the help of microbes. 
v. Bacterial and fungal toxins which can destroy pests and pathogens can be directly 
integrated into plants with the help of biotechnology. Similar to bacteria, some species 
of fungi and viruses are useful as pesticides. Spinosad, a byproduct of fermentation is a 
biopesticide. 
Q. 3. E. Answer the following. 
 
Which are the reasons for increasing the popularity of probiotic products? 
Answer : i. Probiotics are milk products that contain active bacteria like Lactobacillus. 
These microbes maintain the balance of intestinal microorganisms i.e. increase the 
population of microbes helping the digestion and decrease the population of harmful 
microbes (ex. Clostridium). 
ii. These products form the colonies of useful microbes in alimentary canal and control 
other microbes and their metabolic activities, improve resistance and lower the ill-effects 
of harmful substances formed during metabolic activities. 
Page 4


Introduction to Microbiology 
Exercise 
Q. 1. Rewrite the following statements using correct of the options and explain 
the completed statements. 
 
(gluconic acid, coagulation, amino acid, acetic acid, clostridium, lactobacilli) 
a. Process of -- -- -- -- of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like -- -- -- in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is -- -- --. 
d. Salts which can be used as supplement of calcium and iron are obtained from -
------ acid. 
Answer : a. Process of coagulation of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like clostridium in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is acetic acid. 
d. Salts which can be used as supplement of calcium and iron are obtained from 
gluconic acid. 
Q. 2. Match the pairs 
 
 
Answer : 
 
Q. 3. A. Answer the following. 
 
Which fuels can be obtained by microbial processes? Why is it necessary to 
increase the use of such fuels? 
Answer : i. Gaseous fuel- methane can be obtained by microbial anaerobic 
decomposition of urban agricultural and industrial waste. 
ii. Ethanol, an alcohol is a clean (smokeless) fuel obtained during fermentation of 
molasses by the yeast- Saccharomyces. 
iii. Hydrogen gas is considered to be the fuel of future. Hydrogen gas is released during 
bio-photolysis of water in which bacteria perform the photo-reduction. 
It is necessary to increase the use of these fuels so that the fuels that are obtained from 
the non-renewable energy sources can be conserved. Also, air pollution can be 
reduced. 
Q. 3. B. Answer the following. 
 
How can the oil spills of rivers and oceans be cleaned? 
Answer : i. Spilling of petroleum oil occurs in ocean due to various reasons. 
ii. This oil may prove fatal and toxic to aquatic organisms. 
iii. It is not easy to remove the oil layer from surface of water by mechanical method. 
However, bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the 
ability to destroy the pyridines and other chemicals. 
iv. Hence, these bacteria are used to clear the oil spills. These are called as 
hydrocarbon clastic bacteria (HCB). HCB decompose the hydrocarbons and bring about 
the reaction of carbon with oxygen. CO2 and water is formed in this process. 
Q. 3. C. Answer the following. 
 
How can the soil polluted by acid rain be made fertile again? 
Answer : i. Sulphuric acid is present in the acid rain and materials coming out of mines. 
The erosion of metals present in statues, bridges and buildings occurs due to it. 
ii. Sulphuric acid is source of energy for some species of bacteria like Acidophillium 
spp. and Acidobacillus ferroxidens. Hence, these bacteria can control the soil pollution 
occurring due to acid rain. 
Q. 3. D. Answer the following. 
 
Explain the importance of biopesticides in organic farming. 
Answer : i. Some microbes-containing inoculants are produced by process of 
fermentation. These inoculants are sprayed on seeds before sowing and some of the 
inoculants are released into plants. 
ii. Solution containing Azotobacter and artificial nitrogenase is used in organic farming. 
iii. Soil pollution occurring due to chemical fertilizers is prevented due to use of these 
solutions. 
iv. Pesticides in the soil can be destroyed with the help of microbes. 
v. Bacterial and fungal toxins which can destroy pests and pathogens can be directly 
integrated into plants with the help of biotechnology. Similar to bacteria, some species 
of fungi and viruses are useful as pesticides. Spinosad, a byproduct of fermentation is a 
biopesticide. 
Q. 3. E. Answer the following. 
 
Which are the reasons for increasing the popularity of probiotic products? 
Answer : i. Probiotics are milk products that contain active bacteria like Lactobacillus. 
These microbes maintain the balance of intestinal microorganisms i.e. increase the 
population of microbes helping the digestion and decrease the population of harmful 
microbes (ex. Clostridium). 
ii. These products form the colonies of useful microbes in alimentary canal and control 
other microbes and their metabolic activities, improve resistance and lower the ill-effects 
of harmful substances formed during metabolic activities. 
iii. Useful microbes become inactive due to antibiotics; probiotics make them active 
again. Nowadays, probiotics are used for treatment of diarrhoea and treatment of 
poultry too. 
Q. 3. F. Answer the following. 
 
How the bread and other products produced using baker’s yeast are nutritious? 
Answer : i. Different types of breads are produced from flour of cereals. Dough 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 in to carbon 
dioxide (CO2) and ethanol. 
iii. Dough rises up due to CO2 and the bread becomes spongy. 
iv. Compressed yeast is used in commercial bakery industry. It is available in dry, 
granular form for domestic use. 
v. Yeast produced for commercial use contains various useful contents like 
carbohydrates, fats, proteins, various vitamins, and minerals. 
vi. Due to this, bread and other products produced with the help of yeast become 
nutritive. 
Q. 3. G. Answer the following. 
 
Which precautions are necessary for proper decomposition of domestic waste? 
Answer : i. In villages, domestic sewage is disposed off either in nearby soil or in 
biogas plant. However, in cities, sewage needs to be carried to processing unit and 
acted upon by microbial processes. 
ii. Segregation of dry and wet waste should be done at household level itself. 
iii. Dry waste can be dumped in garbage bins which can further be used in the landfill 
processes. 
iv. Wet waste can be used for the preparation of compost. 
Q. 3. H. Answer the following. 
 
Why is it necessary to ban the use of plastic bags? 
Page 5


Introduction to Microbiology 
Exercise 
Q. 1. Rewrite the following statements using correct of the options and explain 
the completed statements. 
 
(gluconic acid, coagulation, amino acid, acetic acid, clostridium, lactobacilli) 
a. Process of -- -- -- -- of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like -- -- -- in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is -- -- --. 
d. Salts which can be used as supplement of calcium and iron are obtained from -
------ acid. 
Answer : a. Process of coagulation of milk proteins occurs due to lactic acid. 
b. Harmful bacteria in like clostridium in the intestine are destroyed due to probiotics. 
c. Chemically, vinegar is acetic acid. 
d. Salts which can be used as supplement of calcium and iron are obtained from 
gluconic acid. 
Q. 2. Match the pairs 
 
 
Answer : 
 
Q. 3. A. Answer the following. 
 
Which fuels can be obtained by microbial processes? Why is it necessary to 
increase the use of such fuels? 
Answer : i. Gaseous fuel- methane can be obtained by microbial anaerobic 
decomposition of urban agricultural and industrial waste. 
ii. Ethanol, an alcohol is a clean (smokeless) fuel obtained during fermentation of 
molasses by the yeast- Saccharomyces. 
iii. Hydrogen gas is considered to be the fuel of future. Hydrogen gas is released during 
bio-photolysis of water in which bacteria perform the photo-reduction. 
It is necessary to increase the use of these fuels so that the fuels that are obtained from 
the non-renewable energy sources can be conserved. Also, air pollution can be 
reduced. 
Q. 3. B. Answer the following. 
 
How can the oil spills of rivers and oceans be cleaned? 
Answer : i. Spilling of petroleum oil occurs in ocean due to various reasons. 
ii. This oil may prove fatal and toxic to aquatic organisms. 
iii. It is not easy to remove the oil layer from surface of water by mechanical method. 
However, bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the 
ability to destroy the pyridines and other chemicals. 
iv. Hence, these bacteria are used to clear the oil spills. These are called as 
hydrocarbon clastic bacteria (HCB). HCB decompose the hydrocarbons and bring about 
the reaction of carbon with oxygen. CO2 and water is formed in this process. 
Q. 3. C. Answer the following. 
 
How can the soil polluted by acid rain be made fertile again? 
Answer : i. Sulphuric acid is present in the acid rain and materials coming out of mines. 
The erosion of metals present in statues, bridges and buildings occurs due to it. 
ii. Sulphuric acid is source of energy for some species of bacteria like Acidophillium 
spp. and Acidobacillus ferroxidens. Hence, these bacteria can control the soil pollution 
occurring due to acid rain. 
Q. 3. D. Answer the following. 
 
Explain the importance of biopesticides in organic farming. 
Answer : i. Some microbes-containing inoculants are produced by process of 
fermentation. These inoculants are sprayed on seeds before sowing and some of the 
inoculants are released into plants. 
ii. Solution containing Azotobacter and artificial nitrogenase is used in organic farming. 
iii. Soil pollution occurring due to chemical fertilizers is prevented due to use of these 
solutions. 
iv. Pesticides in the soil can be destroyed with the help of microbes. 
v. Bacterial and fungal toxins which can destroy pests and pathogens can be directly 
integrated into plants with the help of biotechnology. Similar to bacteria, some species 
of fungi and viruses are useful as pesticides. Spinosad, a byproduct of fermentation is a 
biopesticide. 
Q. 3. E. Answer the following. 
 
Which are the reasons for increasing the popularity of probiotic products? 
Answer : i. Probiotics are milk products that contain active bacteria like Lactobacillus. 
These microbes maintain the balance of intestinal microorganisms i.e. increase the 
population of microbes helping the digestion and decrease the population of harmful 
microbes (ex. Clostridium). 
ii. These products form the colonies of useful microbes in alimentary canal and control 
other microbes and their metabolic activities, improve resistance and lower the ill-effects 
of harmful substances formed during metabolic activities. 
iii. Useful microbes become inactive due to antibiotics; probiotics make them active 
again. Nowadays, probiotics are used for treatment of diarrhoea and treatment of 
poultry too. 
Q. 3. F. Answer the following. 
 
How the bread and other products produced using baker’s yeast are nutritious? 
Answer : i. Different types of breads are produced from flour of cereals. Dough 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 in to carbon 
dioxide (CO2) and ethanol. 
iii. Dough rises up due to CO2 and the bread becomes spongy. 
iv. Compressed yeast is used in commercial bakery industry. It is available in dry, 
granular form for domestic use. 
v. Yeast produced for commercial use contains various useful contents like 
carbohydrates, fats, proteins, various vitamins, and minerals. 
vi. Due to this, bread and other products produced with the help of yeast become 
nutritive. 
Q. 3. G. Answer the following. 
 
Which precautions are necessary for proper decomposition of domestic waste? 
Answer : i. In villages, domestic sewage is disposed off either in nearby soil or in 
biogas plant. However, in cities, sewage needs to be carried to processing unit and 
acted upon by microbial processes. 
ii. Segregation of dry and wet waste should be done at household level itself. 
iii. Dry waste can be dumped in garbage bins which can further be used in the landfill 
processes. 
iv. Wet waste can be used for the preparation of compost. 
Q. 3. H. Answer the following. 
 
Why is it necessary to ban the use of plastic bags? 
Answer : i. Plastic bags pollute water as well as land. Littering of these bags gets 
clogged at the water sources. 
ii. They are manufactured from polypropylene which is a material manufactured from 
non-renewable sources like mineral oil and petroleum. 
iii. Plastic bags are undegradable and are not recycled easily. 
iv. They are harmful for marine animals and wild life creatures. 
v. Hence, its necessary to ban plastic bags. 
Q. 4. Complete the following conceptual picture. 
 
 
Answer : 
 
Q. 5. A. Give scientific reasons. 
 
Use of mutant strains has been increased in industrial microbiology. 
Answer : During industrial production of milk products, strict cleanliness and 
sterilization is essential as bacteria can be attacked by viruses. Hence, virus-resistant