Chapter 7 Introduction to Microbiology Solutions

[Note: In examination match the column question will ham 2 components in Column ‘A’ with 4 alternatives in Column ‘B’.]

b. How can the oil spills of rivers and oceans be cleaned?
Answer:

c. How can the soil polluted by acid rain be made fertile again?
Answer:

d. Explain the importance of bio pesticides in organic farming.
Answer:

e. What are the reasons for increasing the popularity of probiotic products?
Answer:

All these facts have made probiotics a popular choice for people.

f. How the bread and other products produced using baker’s yeast are nutritious?
Answer:

g. Which precautions are necessary for proper decomposition of domestic waste?
Answer:
The domestic waste should be properly segregated into biodegradable (wet waste) and non-biodegradable (dry waste). After segregation, these wastes should be stored separately into two different containers. The non-biodegradable substances should he either reused or sent for recycling. The biodegradable substances are decomposed naturally.

The decomposition process can be done at house-hold level too in a pot or a tank. This decomposition will yield a rich manure. The pot should be covered by a thin layer of soil and it should be kept in a dark but airy place.

The non-biodegradable things such as plastic articles, glass pieces, metal objects, unused 5 medicines, e-waste should never be thrown in wet wastes. The toxic substances and the insecticides if added to wet waste, will never allow the natural decomposition process. Therefore, only after taking proper precautions we can aim at proper decomposition of domestic wastes.

h. Why is it necessary to ban the use of plastic bags?
Answer:
Plastic is a non-biodegradable substance. It cannot be degraded back into its original constituents. It remains just like that for many hundreds of years. It causes solid waste pollution in any environment wherever it is thrown indiscriminately. If burnt, it releases very toxic gases. If dumped in landfills it obstructs the other decomposition processes.

If thrown in water bodies, it causes harm to aquatic life. Cattle graze on plastic unknowingly and are killed by it as it clogs inside their alimentary canal. The gutters and rain water drains get clogged due to plastic bags and this causes cities to submerge in water during heavy rains. Nowadays, the fishermen get more than half of plastic if they cast their net in the sea.

People use the plastic bags indiscriminately without any thought towards their environmental impact. There are better alternatives for plastic bags such as cloth bags which can be reused again and again. Therefore, it is absolutely necessary to ban the use of plastic bag.

b. Enzymes obtained by microbial process are mixed with detergents.
Answer:

c. Microbial enzymes are used instead of chemical catalysts in chemical industry. (March 2019)
(OR)
Microbial enzymes are said to be eco-friendly.
Answer:

b. What are the benefits of mixing ethanol with petrol and diesel?
Answer:
When only diesel or petrol is used as fuel, there is increased air pollution. Morevoer, since these are non-renewable and exhaustible fuels, they will be finished in next some years. When petrol and diesel is mixed with ethanol, the proportion of CO₂, CO, and hydrocarbons which are emitted in the atmosphere becomes lesser.

The particulate pollutants which otherwise are emitted through combustion of petrol and diesel are not formed when fuels are mixed with ethanol. By adding ethanol to the fuels, the cost of expensive petrol or diesel also becomes less. The ethanol burns more efficiently hence ethanol is mixed with petrol and diesel.

c. Which plants are cultivated to obtain the fuel?
Answer:

d. Which fuels are obtained from biomass?
Answer:
From biomass, the biogas and biodiesel are mainly obtained. The biogas is obtained from dung of cattle. The fermentation of cattle dung gives rise to methane. From methane, methanol is obtained. Ethanol is obtained from molasses of sugarcane and some other crops. In some countries, special crops are cultivated for the biodiesel.

e. How does the bread become spongy?
Answer:

Project: (Do it your self)

Project 1.
Find the ways to implement the zero garbage system at domestic level.

Project 2.
Which are the microbes that destroy the chemical pesticides in soil?

Project 3.
Collect more information about reasons for avoiding the use of chemical pesticides.

Can you recall? (Text Book Page No. 77)

Use your brain power. (Text Book Page No. 79)

(Use your brain power. (Text Book Page No. 81)

Let’s Think: (Text Book Page No. 83)

Question.1
Why is it asked to segregate wet and dry waste in each home?
Answer:
The wet waste decomposes on its own as most of the matter therein is biodegradable. This waste can be converted into manure by composting. The dry waste can be picked up by the bhangarwala or kabadiwala. This waste can be reused or recycled. Therefore, if dry and wet wastes are kept separately, the solid waste management becomes much easier.

On the contrary if everything is dumped indiscriminately, it adds to the total volume of the solid wastes. This becomes unmanageable. Therefore, to reduce the problems of solid waste management, the dry and wet waste segregation must be done at every point source. This also could fetch wealth from waste.

Choose the correct alternative and write its alphabet against the sub-question number:

Match the pairs:

Column ‘A’

Column ‘B’

(1) Vinegar

(a) Polylactic acid

(2) Xanthan gum

(b) Molasses

(c) Icecreams and puddings

(d) Acetic acid

Find the correlation:

Name the following:

Complete the charts:

Fruit

Microbe used

Name of beverage

___________________________

___________________________

Coffee

Theobroma cacao

Candida, Hansenula, Pichia, Saccharomyces

___________________________

Grapes

___________________________

___________________________

Apple

Saccharomyces cerevisiae

___________________________

Fruit

Microbe used

Name of beverage

Caffea arabica

Lactobacillus  brevis

Coffee

Theobroma cacao

Candida, Hansenula, Pichia, Saccharomyces

Cocoa

Grapes

Saccharomyces  cerevisiae

Wine

Apple

Saccharomyces cerevisiae

Cider

Source

Microbe

Amino acid

Use

Sugar and beet molasses, ammonia salt

___________________

___________________

Production of monosodium glutamate (Ajinomoto).

___________________

Aspergillus niger

___________________

Drinks, toffees, chocolate production.

Glucose, corn steep liquor

___________________

Gluconic acid

___________________

Molasses, corn steep liquor

Lactobacillus delbrueckii

___________________

___________________

___________________

Aspergillus itaconius

Itaconic acid

___________________

Source

Microbe

Amino acid

Use

Sugar and beet molasses, ammonia salt

Brevibacterium, Corynobacterium

L-glutamic acid

Production of monosodium glutamate (Ajinomoto).

Sugar molasses, salt

Aspergillus niger

Citric acid

Drinks, toffees, chocolate production.

Glucose, corn steep liquor

Aspergillus niger

Gluconic acid

Production of minerals used as  supplement for calcium and iron.

Molasses, corn steep liquor

Lactobacillus delbrueckii

Lactic acid

Source of nitrogen, production of vitamins.

Molasses, corn steep liquor

Aspergillus itaconius

Itaconic acid

Paper, textile, plastic industry, gum production

Source

Microbe

Amino acid

(1) Sugar molasses and salt

___________________

Citric acid

(2) ___________________

Lactobacillus delbrueckii

___________________

(3) Corn steep liquor

Aspergillus itaconius

___________________

Source

Microbe

Amino acid

(1) Sugar molasses and salt

Aspergillus niger

Citric acid

(2) Molasses, corn steep liquor

Lactobacillus delbrueckii

Lactic acid

(3) Corn steep liquor

Aspergillus itaconius

Itaconic acid

Answer the following questions:

(b) The sludge formed in this process, is used as fertilizer.

(b) Why is it essential to ban plastic bags?
Answer:
Plastic is a non-biodegradable substance. It cannot be degraded back into its original constituents. It remains just like that for many hundreds of years. It causes solid waste pollution in any environment wherever it is thrown indiscriminately. If burnt, it releases very toxic gases. If dumped in landfills it obstructs the other decomposition processes.

If thrown in water bodies, it causes harm to aquatic life. Cattle graze on plastic unknowingly and are killed by it as it clogs inside their alimentary canal. The gutters and rain water drains get clogged due to plastic bags and this causes cities to submerge in water during heavy rains. Nowadays, the fishermen get more than half of plastic if they cast their net in the sea.

People use the plastic bags indiscriminately without any thought towards their environmental impact. There are better alternatives for plastic bags such as cloth bags which can be reused again and again. Therefore, it is absolutely necessary to ban the use of plastic bag.

Write short notes on the following:

Complete the paragraph by choosing the appropriate words given in the brackets:

Read the paragraph and answer the questions given below:

Remediation is the process of removing dangerous or poisonous substances from the environment, or limiting the effect that they have on it. When any biological organism is used for remediation, it is called bioremediation. When plant species are used for the purpose of remediation, it is called phytoremediation. When any microbes are used then it is named as microbial remediation. The methods of such remediation have helped to clean the environment from toxic effluents, especially sewage and crude oil. Dr. Anand Chakraborty, a scientist of Indian origin, has worked on Pseudomonas aeruginosa which have reduced the crude oil films into carbon dioxide and water.

Questions and Answers:

Diagram based questions:

(b) What type of waste is used in this method?
Answer:
In this method only degradable waste matter collected in cities can be used. Such solid waste can undergo biodegradation and hence can be managed in an eco-friendly way.

(c) What kind of useful substances can be obtained from such methods?
Answer:
From such decomposition, organic fertilizers and manure formed through composting are obtained. Methane gas is also obtained which is used as fuel.

(b) Explain the process in short.
Answer:
Land-filling sites:

Activity based questions:

(ii) How the sewage generated in your house or apartment is disposed off ?
Answer:
The sewage generated in our house is carried by the drainage pipes to municipal sewage treatment plants. Here, primary, secondary and tertiary treatment is done on the sewage. The safe water is then released into the ocean.

(ii) How can that factor be managed with the help of microbes?
Answer:
Microbes which can destroy the pathogens of cholera, typhoid, etc. are mixed with sewage. They release methane and CO₂by decomposition of the carbon compounds present in sewage. Other microbes that decompose chemical compounds are also released. Phenol oxidizing bacteria decompose the xenobiotic chemicals present in sewage.

(iii) How are the oil spills in oceans cleared?
Answer:
Hydrocarbonoclastic bacteria like
Alcanivorax borkumensis and Pseudomonas are used to clear the oil spillage from ocean water. These bacteria decompose the hydrocarbons. They bring about the reaction of released carbon with oxygen to produced CO₂and water.

Projects: (Do it your self)

Project 1.
Search: (Textbook page no. 81)
Read the ingredients and their proportion printed on bottles of cold drinks and juices and wrappers of ice creams. Find out the natural and artificial ingredients.

Project 2.
Internet is My Friend: (Textbook page no. 85)
Collect pictures of various useful microbes. Display chart of their information in the classroom.

Project 3.
Observe the figure given on Textbook page no. 82. Discuss about bio-fuel?