Important Questions Class 12 Biology Chapter 10 Microbes In Human Welfare for CBSE

Important Questions for Class 12 Biology 1st Chapter Microbes In Human Welfare MCQ, Very Short, Short Type, Long Type

CBSE Class 12 Important Questions for Class 12 Biology Chapter 10 Microbes In Human Welfare all MCQ Type, Very Short Type, Assertion Reason Type, Case Study, Short Type and Long Type Questions with Answers by Expert. Important Questions for Section A, B, C, D Class 12 Biology Chapter 10.

  • Answer in one sentence

1.) What are fermenters?

Ans. On a big scale, industrial production necessitates the cultivation of microorganisms in fermenters, which are extremely large vessels.

2.) What are antibiotics?

Ans. Antibiotics are chemical molecules produced by certain bacteria that can kill or slow down the growth of other (disease-causing) bacteria.

3.) What is clot buster?

Ans. Streptokinase, a ‘clot buster’ produced by the bacterium Streptococcus and modified by genetic engineering, is used to remove clots from the blood arteries of individuals who have had a myocardial infarction which can lead to heart attack.

4.) Define BOD

Ans. The amount of oxygen consumed if all of the organic matter in one liter of water was oxidized by bacteria is referred to as BOD.

5.) Describe formation of activated sludge?

Ans. The effluent is fed into a settling tank where the bacterial ‘flocs’ are allowed to settle after the BOD of sewage or waste water has been decreased considerably. these sediments are called Activated sludge

4.) Give examples of biogases. Where are they produced in sewage treatment?

Ans. Common examples of biogases are methane, hydrogen sulphide and carbon dioxide. They are produced in large tanks called anaerobic sludge digesters.

5.) Can Trichoderma be used as a biocontrol agent?

Ans. YES, fungus Trichoderma is a biological control being developed for use in the treatment of plant disease. Trichoderma fungi are free-living fungi found in abundance in root habitats. They work as biocontrol agents for a variety of plant diseases.

  • Answer in short

1.) Explain the process by which lactic acid bacteria convert milk to curd?

Ans. 1.) Lactobacillus and other lactic acid bacteria (LAB) thrive in milk, converting it to curd.

2.) The LAB produces acids that coagulate and partially breakdown milk proteins as they develop.

3.) A little amount of curd added to fresh milk as an inoculum or starter contains millions of LAB, which multiply at appropriate temperatures, converting milk to curd,

4.) It improves the nutritional quality of the milk by increasing vitamin B12.

2.) Describe in brief the primary treatment process in sewage treatment.

Ans. The primary treatment procedures entail the physical removal of large and tiny particles from sewage by filtering and sedimentation.

2.) These are removed in phases; the floating debris is removed first, followed by sequential filtration.

3.) The grit (dirt and small pebbles) is then washed away by sedimentation.

4.) The primary sludge is made up of all solids that settle, whereas the effluent is made up of the supernatant.

5.) Secondary treatment is performed on the effluent from the initial settling tank.

3.) Explain the role of microorganisms in enzyme production with suitable example

Ans. 1.) Enzyme synthesis is carried out by microbes.

2.) Lipases are enzymes that are found in detergent formulas and aid in the removal of greasy stains from clothing.

3.) bottled fruit juices from the store are clearer due to the employment of pectinases and proteases to clarify the bottled juices.

4.) Streptokinase, a ‘clot buster’ produced by the bacterium Streptococcus and modified by genetic engineering, is used to remove clots from the blood arteries of individuals who have had a myocardial infarction (heart attack).

5.) these are some of the common examples of enzymes produced by microbes.

Q 4.) Baculoviruses used as biological control agents. Justify

Ans. 1.) Baculoviruses are arthropod-borne diseases that infect insects.

2.) The genus Nucleopolyhedrovirus contains the bulk of baculoviruses employed as biological control agents. 3.) These viruses are ideal possibilities for insecticidal applications that are species-specific and have a restricted scope.

4.) Plants, mammals, birds, fish, and even non-target insects have been proven to be unaffected by them.

5.) This is especially important when preserving beneficial insects as part of an overall integrated pest management (IPM) program or when treating an environmentally sensitive area.

Q.5) Explain Role of methanogens in rumen of cattle

Ans. 1.) Methanogenic bacteria can also be found in cattle’s rumen (a portion of the stomach).

2.) The rumen contains a large amount of cellulosic material that is found in cattle feed.

3.) These bacteria aid in the digestion of cellulose in the rumen and play a vital role in cattle nutrition.

  • Answer in brief

Q.1) Explain biofertilizers with examples

Ans. 1.) Biofertilizers are organisms that improve the soil’s nutrient quality.

2.) Bacteria, fungus, and cyanobacteria are the most common biofertilizers.

3.) The nodules created by Rhizobium’s symbiotic relationship on the roots of leguminous plants. 4.) These bacteria convert atmospheric nitrogen into organic forms that the plant can utilize as a nutrition.

5.) Other bacteria, such as Azospirillum and Azotobacter, can fix atmospheric nitrogen while free-living in the soil, increasing the nitrogen content of the soil.

6.) Plants and fungi are known to create symbiotic relationships (mycorrhiza).

7.) Mycorrhizae are formed by many species of the Glomus genus. In these connections, the fungal symbiont obtains phosphorus from the soil and passes it on to the plant.

9.) Other advantages of plants with such relationships include resistance to root-borne diseases, tolerance to salinity and drought, and an overall improvement in plant growth and development. 10.) Cyanobacteria, such as Anabaena, Nostoc, and Oscillatoria, are autotrophic microbes that are found in both aquatic and terrestrial habitats and can fix atmospheric nitrogen.

11.) Cyanobacteria are an essential biofertilizer in paddy crops.

12.) In addition to adding organic matter to the soil, blue green algae increase its fertility.

Q.2) Describe with the help of an example how biological control of pests and diseases is carried out.

Ans. 1.) Bacillus thuringiensis is one example of a microbial biocontrol agent that can be used to control butterfly caterpillars (often written as Bt ).

2.) These come in sachets as dried spores that are mixed with water and sprayed onto sensitive plants like brassicas and fruit trees, where insect larvae feed them.

3.) The toxin is released in the intestines of larvae, killing them.

4.) The caterpillars will be killed by a bacterial disease, but other insects will be unaffected.

5.) Scientists have inserted B. thuringiensis toxin genes into plants as a result of the development of genetic engineering tools in the last decade or so.

6.) Insect pests cannot infect to such resistant plants.

7.) Bt-cotton is one such example, which is grown in parts of our country’s states.

Q.3) Describe biological waste treatment process.

Ans. 1.) The primary effluent is fed into enormous aeration tanks where it is mechanically stirred and pumped with air.

2.) This promotes the rapid growth of beneficial aerobic microorganisms in flocs (masses of bacteria associated with fungal filaments to form mesh like structures).

3.) These microorganisms devour the majority of the organic materials in the wastewater as they grow.

4.) The effluent’s BOD (biochemical oxygen demand) is greatly reduced as a result of this.

5.) The sewage water is treated till the BOD level falls below a certain threshold.

6.) After the BOD of sewage has been lowered considerably, the effluent is fed into a settling tank where bacterial ‘flocs’ can settle.

7.) Activated sludge is the name for this type of silt.

8.) To serve as the inoculum, a small portion of the activated sludge is fed back into the aeration tank.

9.) The sludge that remains is poured into enormous tanks known as anaerobic sludge digesters. 10.) Other bacteria, which can thrive anaerobically, consume the bacteria and fungi in the sludge here.

11.) Bacteria produce a combination of gases during digestion, including methane, hydrogen sulphide, and carbon dioxide.

12.) These gases combine to generate biogas, which is combustible and can be utilised as a source of energy.

13.) Generally, the effluent from the secondary treatment facility is discharged into natural water bodies such as rivers and streams.

Q.4) Short note: biogas plant

Ans. 1.) The biogas plant is made up of a concrete tank (10-15 feet deep) that collects bio-waste and feeds it a slurry of manure.

2.) A floating cover is placed over the slurry, which continues to rise as the microbial activity in the tank produces gas.

3.) The biogas plant has an outlet that is connected to a pipe that distributes biogas to surrounding residences.

4.) The spent slurry is removed and can be used as fertiliser through another exit. In rural locations where cattle are employed for a number of reasons, cattle excrement is readily available in big amounts.

5.) As a result, biogas facilities are increasingly commonly constructed in rural areas.

6.) The resulting biogas is used for cooking and lighting.

MCQs

1.) Assertion: Wine and beer are produced without distillation

Reason: Depending on the type of the raw material used for fermentation and the type of processing (with or without distillation) different types of alcoholic drinks are obtained.

a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.

c.) If assertion is true but the reason is false.

d.) If both assertion and reason are false.

2.) Penicillium is an antibiotic produced by

a) Penicillium notatum

b) Penicillium chrysogenum

c) Penicillium citrinum

d) Penicillium brefeldianum

3.) Assertion: BOD is a measure of the organic matter present in the water.

Reason: A smaller value of BOD of waste water, more is its polluting potential.

a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.

c.) If assertion is true but the reason is false.

d.) If both assertion and reason are false. 

4.) Which of the following organism is used in the production of butyric acid?

a) Aspergillus niger

b) Acetobacteraceti

c) Clostridium butylicum

d) Lactobacillus

5.) Assertion: Yeast is a fermentation agent.

Reason: The puffed-up appearance of dough is due to the production of CO2 gas.

a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.

c.) If assertion is true but the reason is false.

d.) If both assertion and reason are false.

6.) Assertion: Acetic acid production involves aerobic process only

Reason: acid formation takes place ion presence of oxygen and does not require anaerobic process

a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.

c.) If assertion is true but the reason is false.

d.) If both assertion and reason are false.

7.) The Ministry of Environment and Forests has initiated

a) River water pollution prevention act

b) Ganga ActionPlan and

c) Yamuna Action Plan

d) Both b.) and c.)

8.) Whose concentration rises as lactic acid bacteria convert milk into curd?

a) vitamin B12

b) amino acids

c) vitamin k

d) fats

9.) Fungus Trichoderma is used as a

a) biofertilizer

b) biocontrol agent

c) fermenting agent

d) bioactive compound production

10) In the following which bacteria can fix atmospheric nitrogen while free-living inthe soil

a) Rhzobium

b) Azospirillum

c) Bradyrhizobium

d) Anabaena

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