Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

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Reviewing AP Inter 2nd Year Botany Study Material Chapter 4 Microbes in Human Welfare Questions and Answers can help students prepare confidently for exams.

AP Inter 2nd Year Botany 4th Lesson Microbes in Human Welfare Questions and Answers

IV. Very Short Answer Questions

Question 1.
Why does Swiss cheese have big holes? Name the bacteria responsible for it.
Answer:

  1. The large holes seen in Swiss cheese are formed due to the release of significant amounts of carbon dioxide (CO2) during fermentation.
  2. The bacterium Propionibacterium sharmanii is responsible for producing these holes.

Question 2.
What are fermentors?(AP MAY-17, 22)
Answer:
Fermentors are large-scale containers used for the commercial production of beverages, antibiotics, and other microbial products.

Question 3.
Name any two industrially important enzymes. (AP Mar-19)(AP Mar-17,19, 22)
Answer:
Examples of industrially important enzymes are: Amylase, Lipase, Streptokinase.

Question 4.
What are Baculoviruses?
Answer:

  1. Baculoviruses are viruses that specifically infect insects and other arthropods.
  2. They are widely used as biological control agents, and most belong to the genus Nucleopolyhedrovirus.

Question 5.
Which group of bacteria is found in both the rumen of cattle and sludge of sewage treatment plants?
Answer:
Methanogens.

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

Question 6.
Name the scientists who were credited with showing the role of penicillin as an antibiotic.
Answer:

  1. Alexander Fleming discovered penicillin.
  2. Ernst Chain and Howard Florey demonstrated and established its effectiveness as an antibiotic.

Question 7.
Name any one species of fungi used in the production of antibiotics.
Answer:

  1. A fungus commonly used in antibiotic production is Penicillium notatum.
  2. It is the source of the antibiotic Penicillin.

Question 8.
What is sewage? In what way can sewage be harmful to us?
Answer:
Sewage refers to municipal wastewater, which contains human excreta, organic matter, and numerous microorganisms.

  1. Many of these microorganisms may be disease-causing pathogens. Therefore, sewage should not be discharged directly into rivers, lakes, or other natural water bodies without treatment.
  2. Before disposal, it is treated in sewage treatment plants (STPs) using naturally occurring heterotrophic microbes.
  3. If untreated sewage contaminates drinking water sources, it can spread diseases and create health problems in humans and domestic animals.

Question 9.
What is the key difference between primary and secondary sewage treatment?
Answer:

  1. Primary Sewage Treatment: It is a physical process that removes suspended particles through methods such as filtration and sedimentation. It is relatively simple and less costly.
  2. Secondary Sewage Treatment: It is a biological process in which the primary effluent is transferred to aeration tanks where microorganisms degrade organic matter. This method is comparatively more complex, time-consuming, and expensive.

Question 10.
How do biofertilizers enrich the fertility of the soil?
Answer:
Biofertilizers improve soil fertility through the action of living organisms such as bacteria, fungi, and cyanobacteria that enhance soil nutrient availability.

They increase soil fertility through the following processes :

  1. Nitrogen fixation
  2. Phosphate solubilization
  3. Addition of organic matter to the soil.

V. Short Answer Questions

Question 1.
Why are floes important in the biological treatment of waste water?
Answer:
Floes are clusters of aerobic bacteria associated with fungal filaments, forming mesh-like aggregates.
Role of floes in biological treatment:

  1. The primary effluent is transferred into large aeration tanks, where air is continuously supplied, and the contents are mechanically agitated.
  2. These conditions promote the rapid multiplication of beneficial aerobic microorganisms, resulting in the formation of flocs.
  3. While growing, these microbes break down a major portion of the organic matter present in the effluent and thereby reduce its Biochemical Oxygen Demand (BOD).
  4. The treated effluent is then sent to a settling tank where the bacterial flocs settle down.
  5. This settled material is known as activated sludge.
  6. A small portion of the activated sludge is recycled back into the aeration tank to serve as inoculum, while the remaining sludge is transferred to anaerobic sludge digesters.

Question 2.
Name the bacterium responsible for the conversion of milk into curd. Mention two benefits of curd formation.
Answer:
The bacterium responsible for converting milk into curd is Lactobacillus, a member of the group known as Lactic Acid Bacteria (LAB).

Two advantages of curd formation are:

  1. Improved Nutritional Value: The process enhances the nutritional quality of milk by increasing the amount of Vitamin B12.
  2. Protection Against Harmful Microbes: LAB helps maintain a healthy gut environment by suppressing the growth of disease-causing microorganisms in the digestive system.

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

Question 3.
What is BOD? Why is it an important parameter in sewage treatment?
Answer:
BOD (Biochemical Oxygen Demand) is the quantity of oxygen required by microorganisms to decompose the organic matter present in one litre of water.

Importance in sewage treatment:

  • Measure of Organic Pollution: BOD reflects the amount of biodegradable organic matter present in water.
  • Indicator of Water Quality: A higher BOD value indicates greater pollution and a larger amount of organic waste.
  • Useful in Biological Treatment: During secondary treatment, aerobic microbes consume organic matter and help reduce BOD.
  • Assessment of Treatment Efficiency: A decrease in BOD indicates successful sewage treatment and improved water quality.

Question 4.
Define methanogens. Give one example and their role in biogas production.
Answer:
Methanogens are anaerobic microorganisms that grow on cellulosic substrates and produce methane gas along with carbon dioxide and hydrogen in the absence of oxygen. Example: Methanobacterium Role in biogas production:

  • Methanogens function in anaerobic sludge digesters and decompose organic matter.
  • They help break down cellulose-rich material and release biogas.
  • These organisms are also present in the rumen of cattle, where they assist in cellulose digestion.
  • The methane-rich biogas produced is combustible and serves as a valuable fuel for cooking and lighting.

Question 5.
Write two advantages of mycorrhizal association of plants.
Answer:
Mycorrhiza is a mutually beneficial association between the roots of higher plants and certain fungi, commonly belonging to the genus Glomus. In this association, both the plant and the fungus benefit from each other.

Advantages of mycorrhizal association :

  1. Improved Nutrient Absorption: The fungal hyphae spread extensively in the soil and increase the surface area for absorption. They help the plant absorb essential minerals, especially phosphorus, from the soil and transfer them to the plant roots, thereby enhancing plant growth.
  2. Increased Resistance and Better Growth: Plants associated with mycorrhiza show greater resistance to root-borne pathogens and improved tolerance to drought and salinity. As a result, the plants grow healthier and exhibit better overall development.

Question 6.
What is meant by biocontrol? Give one example of microbial biocontrol agent.
Answer:
Biocontrol refers to the use of living organisms or biological methods to manage plant diseases and’pests instead of relying on chemical pesticides.
Example of a microbial biocontrol agent: Bacillus thuringiensis (Bt)

  1. It is a bacterial biocontrol agent used against butterfly caterpillars.
  2. It is available as dried spores that are mixed with water and sprayed on crops.
  3. When insect larvae feed on the treated plants, the toxin becomes active in their gut and kills them.
  4. It specifically targets caterpillars without affecting beneficial insects

VI. Long Answer Questions

Question 1.
Describe the role of microbes in the production of household products with suitable examples.
Answer:
Microorganisms are essential components of the biosphere and occur along with plants and animals. They include bacteria, fungi, protozoa, viruses, and other microscopic forms of life. Many microbes are beneficial and are widely used in the preparation of household products through fermentation.

Important characteristics of microbes:

  1. Wide Distribution: Microorganisms are found everywhere-in soil, water, air, and inside the bodies of plants and animals. They can survive even in extreme habitats such as hot springs, deep oceans, frozen regions, and highly acidic environments.
  2. Microscopic Nature: Most microbes are microscopic and cannot be seen with the naked eye. However, some bacteria and fungi can be grown on nutrient media to form visible colonies for study.
  3. Importance to Human Life: Although some microbes cause diseases, many are useful and play an important role in producing several everyday products.
  4. Dairy Products (Curd): Microorganisms such as Lactobacillus and other Lactic Acid Bacteria (LAB) convert milk into curd. During this process, LAB produce acids that coagulate milk proteins and partially digest them. A small quantity of curd acts as a starter culture and multiplies rapidly under suitable conditions. This process also enhances the nutritional value of milk by increasing Vitamin B12 content.
  5. Fermented Dough (Dosa, Idli and Bread): The batter used for preparing foods such as dosa and idli undergoes fermentation by microbes. The soft and fluffy texture develops because of the release of carbon dioxide (CO2) gas. Similarly, bread making involves the use of baker’s yeast (Saccharomyces cerevisiae).
  6. Traditional Fermented Foods and Drinks: A traditional beverage called Toddy is prepared by fermenting palm sap. Microorganisms are also used in fermenting fish, soybean, and bamboo shoots to prepare different food products.
  7. Cheese Production: Microbes contribute to the manufacture of different varieties of cheese by providing characteristic texture, flavour and aroma. The holes in Swiss cheese are formed due to CO2 produced by Propionibacterium sharmanii. Roquefort cheese develops its special flavour through the action of selected fungi.

Question 2.
Explain the steps involved in secondary sewage treatment and the role of microbes in the process.
Answer:
Secondary sewage treatment, also called biological treatment, utilizes naturally occurring microorganisms to remove organic pollutants from wastewater. Unlike primary treatment, which is mainly physical, this stage depends on microbial activity.

The process involves the following steps:
1. Aeration and Aerobic Digestion:
Process: The primary effluent is transferred into large aeration tanks where it is continuously stirred and supplied with air.
Role of Microbes: Aeration promotes the growth of aerobic microorganisms that form floes, which are aggregates of bacteria associated with fungal filaments.
Reduction of BOD: As these microbes consume organic matter, the Biochemical Oxygen Demand (BOD) of the wastewater decreases considerably.

2. Sedimentation and Activated Sludge:
Process: After BOD is reduced, the effluent is moved into a settling tank.
Role of Microbes: The microbial flocs settle at the bottom and form activated sludge. Inoculum: A small amount of activated sludge is recycled back into the aeration tank to initiate treatment of the next batch.

3. Anaerobic Sludge Digestion:
Process: The remaining activated sludge is transferred into anaerobic sludge digesters.
Role of Microbes: Anaerobic bacteria digest the bacterial and fungal biomass present in the sludge.
Biogas Formation: During digestion, gases such as methane, hydrogen sulphide and carbon dioxide are produced, collectively forming biogas.

4. Final Disposal:

  • After the biological treatment is complete, the treated effluent is generally considered safe enough to be released into natural water bodies like rivers and streams.
  • This microbial methodology has been the primary way of treating millions of gallons of wastewater worldwide for over a century, as no man-made technology has yet rivaled its efficiency. Thus, Secondary sewage treatment relies on microbes to remove organic pollutants, reduce BOD, and produce useful by-products like biogas, making wastewater safe for disposal.

Question 3.
Discuss the industrial applications of microbes in the production of fermented beverages, antibiotics, and bioactive molecules.
Answer:
Microorganisms are extensively employed in industries for producing fermented beverages, antibiotics, and various bioactive compounds. These products are manufactured in large fermenters under controlled environmental conditions.
1. Fermented Beverages: Yeasts are commonly used to prepare alcoholic beverages such as wine, beer, whisky, brandy and rum.

  • Microbe Used: The most widely used yeast is Saccharomyces cerevisiae (brewer’s yeast).
  • Process: It ferments malted cereals and fruit juices to produce ethanol.
  • Products: Wine and beer are obtained without distillation, whereas whisky, brandy and rum are produced after distillation of the fermented broth.

2. Antibiotics:

  • Antibiotics are microbial substances that suppress or destroy disease- causing organisms.
  • Penicillin was the first antibiotic discovered by Alexander Fleming from the fungus Penicillium notatum.
  • The therapeutic value of penicillin was later demonstrated by Ernst Chain and Howard Florey.
  • Antibiotics have greatly reduced deaths caused by diseases such as plague, diphtheria, whooping cough, and leprosy.

3. Bioactive Molecules and Chemicals: Microorganisms are used to manufacture several organic acids, enzymes, and bioactive compounds:

Organic Acids: Examples :

  • Citric acid – Aspergillus niger
  • Acetic acid – Acetobacter aceti
  • Butyric acid – Clostridium butylicum
  • Lactic acid – Lactobacillus

Industrial Enzymes:

  • Lipases – used in detergents for removing oily stains.
  • Pectinases and Proteases – used in clarifying bottled fruit juices.
  • Streptokinase – produced by Streptococcus and used as a ‘clot-buster’.

Bioactive Molecules:

  • Cyclosporin A, produced by Trichoderma polysporum, is used as an immunosuppressant during organ transplantation.
  • Statins, produced by Monascus purpureus, help lower blood cholesterol levels by inhibiting the enzyme responsible for cholesterol synthesis.

Question 4.
Explain the process of biogas production in a typical biogas plant and name the main microbes involved.
Answer:
Biogas is a gaseous fuel mainly consisting of methane (CH4), carbon dioxide (CO2), traces of hydrogen sulphide (H2S), and moisture. It is generated by the anaerobic decomposition of cattle dung, domestic waste, and agricultural residues by microorganisms.

a) Biogas Production from Sludge:

  1. A small amount of activated sludge is recycled back into the aeration tank as inoculum.
  2. In anaerobic digesters, methanogenic bacteria digest the bacterial and fungal biomass present in the sludge.
  3. During digestion, gases such as methane, carbon dioxide, and hydrogen sulphide are released, forming biogas.

b) Biogas Production from Dung:

  1. A biogas plant contains a deep concrete tank in which dung slurry is collected.
  2. A floating cover is placed over the slurry and rises as gas accumulates.
  3. The plant has an outlet connected to pipelines for supplying biogas to nearby houses.
  4. The spent slurry is removed through a separate outlet and is used as an organic fertilizer.

Main Microbes Involved: Methanogens (e.g., Methanobacterium) are the primary microorganisms responsible for biogas production.

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

I. Multiple Choice Questions

Question 1.
Which microbe is commonly used to convert milk into curd?
1. Acetobacter
2. Rhizobium
3. Lactobacillus
4. Clostridium
Answer:
3. Lactobacillus

Question 2.
Penicillin was discovered by :
1. Robert Koch
2. Edward Jenner
3. Louis Pasteur
4. Alexander Fleming
Answer:
4. Alexander Fleming

Question 3.
Which enzyme is used to remove blood clots in heart patients?
1. Lipase
2. Amylase
3. Streptokinase
4. Cellulase
Answer:
3. Streptokinase

Question 4.
The bacterium that produces butyric acid is:
1. Clostridium
2. Acetobacter
3. Lactobacillus
4. Azotobacter
Answer:
1. Clostridium

Question 5.
Swiss cheese holes are due to release of CO2 produced by :
1. Propionibacterium sharmanii
2. Saccharomyces cerevisiae
3. Lactobacillus
4. Penicillium
Answer:
1. Propionibacterium sharmanii

Question 6.
Methanogens are found in :
1. Aerobic soil
2. Vinegar
3. Cold water bodies
4. Rumen of cattle
Answer:
4. Rumen of cattle

Question 7.
The fungus used to produce cyclosporin A is:
1. Penicillium notatum
2. Trichoderma polysporum
3. Aspergillus niger
4. Saccharomyces
Answer:
2. Trichoderma polysporum

Question 8.
Which of the following microbes helps in nitrogen fixation in paddy fields?
1. Acetobacter
2. Penicillium
3. Glomus
4. Nostoc
Answer:
4. Nostoc

Question 9.
The ‘clot buster’ enzyme is produced by:
1. Streptomyces
2. Streptococcus
3. Bacillus
4. Pseudomonas
Answer:
2. Streptococcus

Question 10.
Which gas is predominantly present in biogas?
1. Carbon dioxide
2. Nitrogen
3. Oxygen
4. Methane
Answer:
4. Methane

II. Fill in the Blanks

1. The microbe used for the commercial production of ethanol is ………………………. .
Answer:
Saccharomyces cerevisiae

2. The puffed-up appearance of dough is due to the production of ………………………… .
Answer:
CO2

3. …………………………… beverages are produced without distillation.
Answer:
Wine & Beer

4. ……………………….. antibiotic was extensively used to treat American soldiers wounded in the World War II.
Answer:
Penicillin.

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

5. …………………………… is used in the production of Swiss cheese.
Answer:
Propionibacterium sharmanii

6. During biological treatment, microbes significantly reduce ………………………. by consuming organic matter in effluent.
Answer:
Biochemical Oxygen Demand (BOD)

7. ………………………………. is an immunosuppressive drug obtained from Trichoderma polysporum.
Answer:
Cyclosporin A

8. …………………………….. are the enzymes helpful in removing oily stains from the laundry.
Answer:
Lipases

9. ………………….. is a free-living fungus which is an effective biocontrol agent of several plant pathogens.
Answer:
Trichoderma

10. ……………………….. is an example of a methanogen.
Answer:
Methanobacterium

III. One Word Answer Questions

Question 1.
Which bacterium is responsible for the production of acetic acid?
Answer:
Acetobacter aceti

Question 2.
Name the enzyme commonly used as a ‘clot buster’ in heart attack patients.
Answer:
Streptokinase

Question 3.
Which fungus is known for producing Cyclosporin A?
Answer:
Trichoderma polysporum

Question 4.
Name the yeast that is commercially used for producing statins.
Answer:
Monascuspurpureus

Question 5.
What is the full form of BOD?
Answer:
Biochemical Oxygen Demand

Question 6.
Mention one methanogenic bacterium present in the rumen of cattle.
Answer:
Methanobacterium

Question 7.
Which bacterium acts as a biocontrol agent against butterfly caterpillars?
Answer:
Bacillus thuringiensis

Question 8.
Name a fungal genus that forms mycorrhizal associations.
Answer:
Glomus.

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

Question 9.
Which group of viruses is used as a biological control agent for insect pests?
Answer:
Nucleopolyhedroviruses

Question 10.
Name the traditional Indian beverage prepared by fermenting palm sap.
Answer:
Toddy

Objective Questions

Question 1.
Which bacterium is widely used in converting milk into curd?
1. Bacillus
2. Thiobacillus
3. Lactobacillus
4. Ferrobacillus
Answer:
3. Lactobacillus

Question 2.
LAB (Lactic Acid Bacteria) enhances the nutritional value of curd by increasing the amount of:
1. Vitamin B12
2. Vitamin B1
3. Vitamin B2
4. Vitamin B6
Answer:
1. Vitamin B12

Question 3.
Bread dough fermentation is mainly carried out by:
1. Candida utilis
2. Lactobacillus
3. Saccharomyces cerevisiae
4. Candida lipolytica
Answer:
3. Saccharomyces cerevisiae

Question 4.
The batter used for preparing Idli and Dosa undergoes fermentation by:
1. Bacteria
2. Algae
3. Protozoans
4. Viruses
Answer:
1. Bacteria

Question 5.
Cheese and yoghurt are obtained through the process of:
1. Pasteurisation
2. Fermentation
3. Distillation
4. Dehydration
Answer:
2. Fermentation

Question 6.
Which acid is commonly formed during microbial fermentation?
1. Oxaloacetic acid
2. Lactic acid
3. Fumaric acid
4. Acetic acid
Answer:
2. Lactic acid

Question 7.
Who discovered Penicillin?
1. Louis Pasteur
2. Waksman
3. Alexander Fleming
4. Edward Jenner
Answer:
3. Alexander Fleming

Question 8.
Which one of the following is NOT a beverage?
1. Beer
2. Rum
3. Penicillin
4. Wine
Answer:
3. Penicillin

Question 9.
Large-scale vessels used for culturing microbes are called:
1. Sterilizers
2. Fermenters
3. Autoclaves
4. Stabilizers
Answer:
2. Fermenters

Question 10.
Which was the first antibiotic discovered?
1. Aureomycin
2. Penicillin
3. Ampicillin
4. Tetracycline
Answer:
2. Penicillin

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

Question 11.
Citric acid is commercially produced by:
1. Yeasts
2. Aspergillus niger
3. Penicillium notatum
4. Chaetomium cellulolyticum
Answer:
2. Aspergillus niger

Question 12.
The first artificially synthesized hormone was:
1. Inulin
2. Casein
3. Insulin
4. Collagen
Answer:
3. Insulin

Question 13.
Beer is commonly prepared from:
1. Grapes
2. Molasses
3. Barley
4. Rye
Answer:
3. Barley

Question 14.
Penicillin is obtained from:
1. Fungus
2. Virus
3. Bacterium
4. Algae
Answer:
1. Fungus

Question 15.
Select the incorrect statement regarding antibiotics:
1. Antibiotics are effective only against specific microbes
2. The first antibiotic discovered was penicillin
3. Some individuals may develop allergy to antibiotics
4. An antibiotic can cure any disease
Answer:
1. Antibiotics are effective only against specific microbes

Question 16.
Ethanol production from starch is carried out using:
1. Lactobacillus
2. Azotobacter
3. Acetobacter
4. Saccharomyces
Answer:
4. Saccharomyces

Question 17.
A vaccine is:
1. A treated bacterial, viral, or protein preparation
2. A treated phage
3. A treated alga
4. A treated fungus
Answer:
1. A treated bacterial, viral, or protein preparation

Question 18.
The term “antibiotic” was introduced by:
1. Edward Jenner
2. Waksman
3. Dr. Y. Subba Rao
4. Alexander Fleming
Answer:
2. Waksman

Question 19.
After a viral infection, infected host cells release:
1. Antibody
2. Interferon
3. Antigen
4. Interleukin
Answer:
2. Interferon

Question 20.
What is the scientific name of baker’s yeast?
1. Candida utilis
2. Saccharomyces cerevisiae
3. Candida lipolytica
4. Chaetomium cellulolyticum
Answer:
2. Saccharomyces cerevisiae

Question 21.
Statins are commercially used as:
1. Blood cholesterol-lowering agents
2. Immunosuppressive agents
3. Clot busters
4. Oil-stain removers
Answer:
1. Blood cholesterol-lowering agents

Question 22.
Which enzyme is commonly used to remove oily stains?
1. Pectinase
2. Lipase
3. Urease
4. Sucrase
Answer:
2. Lipase

Question 23.
BOD stands for:
1. Biological Oxygen Demand
2. Biogeographical Oxygen Demand
3. Biochemical Oxygen Demand
4. Biophysical Oxygen Demand
Answer:
3. Biochemical Oxygen Demand

Question 24.
The major constituent of biogas is:
1. Acetone
2. Methane
3. Ethane
4. Ammonia
Answer:
2. Methane

Question 25.
The microorganisms mainly involved in gobar gas plants are:
1. Denitrifying bacteria
2. Nitrogen-fixing bacteria
3. Methanogens
4. Nitrifying bacteria
Answer:
3. Methanogens

Question 26.
Sewage purification is carried out by:
1. Antibiotics
2. Microbes
3. Fertilizers
4. Antiseptics
Answer:
2. Microbes

Question 27.
Baculoviruses specifically infect:
1. Arthropods
2. Coelenterates
3. Annelids
4. Nematodes
Answer:
1. Arthropods

Question 28.
Which of the following is a symbiotic nitrogen-fixing bacterium?
1. Azotobacter
2. Rhizobium
3. Clostridium
4. Azospirillum
Answer:
2. Rhizobium

Question 29.
Which among the following acts as a biofertilizer?
1. Rhizobium and legume association
2. Blue-green algae and Azolla
3. Nostoc and grasses
4. E. coli and legume association
Answer:
2. Blue-green algae and Azolla

Microbes in Human Welfare Questions and Answers AP Inter 2nd Year Botany Chapter 4

Question 30.
Farmers can enhance paddy yield by nearly 50% through the use of:
1. Rhizobium
2. Farmyard manure
3. Cyanobacteria
4. Cyanobacteria and Azolla
Answer:
4. Cyanobacteria and Azolla