MP Board Class 12th Biology Solutions Chapter 10 Microbes in Human Welfare
Microbes in Human Welfare NCERT Text Book Questions And Answers
Question 1.
Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?
Answer:
Curd can be used as a sample for the study of microbes. Curd contains numerous Lactic Acid Bacteria (LAB) or Lactobacillus. These bacteria produce acids that coagulate and digest milk proteins. A small drop of curd contains millions of bacteria, which can be easily observed under a microscope.
Question 2.
Give example to prove that microbes release gases during metabolism.
Answer:
The dough of dosa and idli is fermented by bacteria while the dough of bread is fermented by yeast. The puffed-up appearance is due to CO2 gas production.
Question 3.
In which food would you find lactic acid bacteria? Mention some of their useful applications.
Answer:
Lactic acid bacteria can be found in curd. It is this bacterium that promotes the formation of milk into curd. The bacterium multiplies and increases its number, which converts the milk into curd. They also increase the content of vitamin B12 in curd.
Lactic acid bacteria are also found in our stomach where it keeps a check on the disease-causing microorganisms.
Question 4.
Name some traditional Indian foods made of wheat, rice, and Bengal gram (or their products) which involve the use of microbes.
Answer:
- Bhatura, Bread, Jalebi (wheat).
- Dosa, Idli (Rice)
- Karhi (Bengal gram).
Question 5.
In which way have microbes played a major role in controlling diseases caused by harmful bacteria?
Answer:
Several microorganisms are used for preparing medicines. Antibiotics are medicines produced by certain microorganisms to kill other disease-causing microorganisms. These medicines are commonly obtained from bacteria and fungi. They either kill or stop the growth of disease-causing microorganisms.
Streptomycin, tetracycline and penicillin are common antibiotics. Penicillium notatum produces the chemical penicillin, which checks the growth of staphylococci bacteria in the body. Antibiotics are designed to destroy bacteria by weakening their cell walls.
Question 6.
Name any two species of fungus, which are used in the production of antibiotics.
Answer:
Antibiotics are medicines that are produced by certain microorganisms to kill other disease-causing microorganisms. These medicines are commonly obtained from bacteria and fungi. The species of fungus used in the production of antibiotics are :
Question 7.
What is sewage? In which way can sewage be harmful to us?
Answer:
Sewage is the municipal waste-water collected from city or townhomes, that contains a toilet, bathroom, and kitchen waste.
It contains large amounts of organic matter and many pathogenic microbes which are harmful to humans as they can cause many diseases like cholera, typhoid, polio.
Question 8.
What is the key difference between primary and secondary sewage treatment?
Answer:
Differences between Primary and Secondary sewage treatment:
Question 9.
Do you think microbes can also be used as source of energy? If yes, how?
Answer:
Yes, microbes can be used as a source, of energy. Bacteria such as; Methane bacterium is used for the generation of gobar gas or biogas. The generation of biogas is an anaerobic process in a biogas plant, which consists of a concrete tank (10-15 feet deep) with sufficient outlets and inlets. The dung is mixed with water to form the slurry and thrown into the tank.
The digester of the tank is filled with numerous anaerobic methane-producing bacteria, which produce biogas from the slurry. Biogas can be removed through the pipe which is then used as a source of energy, while the spent slurry is removed from the outlet and is used as a fertilizer.
Question 10.
Microbes can be used to decrease the use of chemical fertilizers and pesticides. Explain how this can be accomplished.
Answer:
Chemical fertilizers are used to increase availability of minerals while pesticides are economically harmfull and toxic to human being, cattles. This disturbs biological environment. Microbes used as fertilizers (bio fertilizes) and pesticide (biopesticide) are not harmful to ecology and humans. Organic farming uses them and provides increased production.
Question 11.
Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B, and C were recorded as 20mg/L, 8 mg/L and400mg/L, respectively, which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean ?
Answer:
- The BOD values of the three samples A, B and C were recorded as 20 trig/L 8 mg/L and400mg/L.
- Greater the BOD of wastewater more is its polluting potential. So, sample C is more polluting as compared to sample A.
- Hence, sample A is the secondary effluent, sample B is river water and sample C is untreated sewage water.
Question 12
Find out the name of microbes from which cyclosporine(animmuno-suppressive drug) and statins (blood cholesterol-lowering agents) are obtained.
Answer:
- Cyclosporin A from Trichoderma polysporum
- Statins from yeast Monascus purpureus.
Question 13.
Find out the role of microbes in die following and discuss it with your teacher,
(a) Single Cell Protein (SCP)
(b) Soil.
Answer:
(a) Single Cell Protein (SCP) refers to harmless microbial cells that can be used as an alternate source of good protein.
Just like mushrooms (a fungus) is eaten by many people and yeast is used by athletes as a protein source; similarly, other forms of microbial cells can also be used as food rich in protein, minerals, fats, carbohydrate and vitamins.
Microbes like SpiruMna and Methylophilus methylophus are being grown on an industrial scale on materials containing starch like waste water from potato processing plants, straw, molasses, animal manure and even sewage. These single cell microbes can be used as source of proteins.
(b) Microbes play an important role in organic farming which is done without the use of chemical fertilizers and pesticides. Bio-fertilizers are living organisms which help increase the fertility of soil. It involves the selection of beneficial microorganisms that help in improving plant growth through the supply of plant nutrients. Bio-fertilizers are introduced in seeds, roots or soil to mobilize the availability of nutrients. Thus, they are extremely beneficial in enriching the soil with organic nutrients.
Many species of bacteria and cyanobacteria have the ability to fix free atmospheric nitrogen, Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen fixing bacteria, whereas Anabena, Nostoc and Oscillitoria are examples of nitrogen-fixing cyanobacteria. Bio-fertilizers are cost effective and eco-freindly.
Microbes can also act as bio-pesticides to control insect pest in plants. An example of bio-pesticides is Bacillus thuringiensis, which produces a toxin that kills the insect pests. Dried bacterial spores are mixed in water and sprayed in agricultural fields. When larvae of insects feed on crops, these bacterial spores enter the gut of the larvae and release toxins, thereby it. Similarly, Trichoderma are free living fungi. They live in the roots of higher plants and protect them from various pathogens. Baculoviruses is another bio-pesticides that is used as a biological control agent against insects and other arthropods.
Question 14.
Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric arid, Penicillin and Curd.
Answer:
Penicillin > Biogas > Curd> Citric Acid.
- Penicillin an antibiotic cures bacterial diseases.
- Biogas is source of energy and pollution-free fuel.
- Curd easily digestible vitamin-rich milk preparation.
- Citric Acid used as preservatives.
Question 15.
How do biofertilizers enrich the fertility of the sofl?
Answer:
Bio-fertilizers are living orgainsms which help in increasing the fertility of soil. It involves the selection of beneficial microorganisms that help in improving plant growth through the supply of plant nutrients. These are introduced to seeds, roots, or soil to mobilize the availability of nutrients by their biological activity. Thus, they are extremely beneficial in enriching die soil with organic nutrients.
Many species of bacteria and cyanobacteria have the ability to fix free atmopheric nitrogen. Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen-fixing bacteria, whereas Anabena, Nostoc and Oscillitoriasie. examples of nitrogen-fixing cyanobacteria. Bio-fertilizers are cost effective and eco-friendly.
Microbes in Human Welfare Other Important Questions And Answers
Microbes in Human Welfare Objective Type Questions
1. Choose the Correct answers:
Question 1.
A milk product which is sours as buttermilk:
(a) Paneer
(b) Curd
(c) Yoghurt
(d) None of these.
Answer:
(b) Curd
Question 2.
Tetracydineisfoundin:
(a) From Strepto ramosus
(b) From Strepto oreofashion
(c) From Strepto freddy
(d) From Strepto nodosum.
Answer:
(a) From Strepto ramosus
Question 3.
Clostridium, Azotobacter, Rizobium increase fertility through:
(a) From nitrogen fixation
(b) From denitrogenation
(c) From imulsification
(d) From vitamin.
Answer:
(a) From nitrogen fixation
Question 4.
The vitamin obtained from Streptomyces olivaceus and Bacillus megaterium:
(a) Vitamin C
(b) Vitamin D
(c) Vitamin E
(d) Vitamin B12
Answer:
(a) Vitamin C
Question 5.
Which of the following is used in the treatment of T.B. leprosy pneumonia:
(a) Bacteriophage
(b) Only virus
(c) Only bacteria
(d) Fungi.
Answer:
(d) Fungi.
Question 6.
How is the virus used in biotechnology and microbiology:
(a) In form of medicine
(b) In form of vector
(c) In water treatment
(d) All of these.
Answer:
(b) In form of vector
Question 7.
Which of the following is useful in bakery product like Indian bread, biscuit, and other product:
(a) Virus
(b) Bacteria
(c) Yeast
(d) Protozoan.
Answer:
(c) Yeast
Question 8.
Which vitamin is found in yeast:
(a) Vitamin C
(b) Vitamin D
(c) B complex
(d) Vitamin A.
Answer:
(c)B complex
Question 9.
Which medicine is obtained from Strepto ramosus:
(a) Terramycine
(b) Niomycine
(c) Erythomycine
(d) Actidine.
Answer:
(a) Terramycine
Question 10.
Nitrosomonas and Nitrobacter bacteria is:
(a) Denitrifying
(b) Nitrifying
(c) Azotobactor
(d) Haimoneproduces.
Answer:
(b) Nitrifying
Question 11.
Through lactic acid bacteria the transformation from milk to curd increases the amount of which vitamin:
(a) Vitamin C
(b) Vitamin D
(c) Vitamin B12
(d) Vitamin E.
Answer:
(c) Vitamin B12
Question 12.
Methanogen is not found in:
(a) Rhumen of cattles
(b) Biogas plant
(c) Bottom of paddy farm
(d) Cell wall of the bacteria.
Answer:
(d) Cell wall of the bacteria.
Question 13.
Water is free from this primary treatment of sewage:
(a) Dissolve impurities
(b) Suspended particle
(c) Harmfull substance
(d) Harmfull Bacteria.
Answer:
(b) Suspended particle
Question 14.
B.O.D. of waste water is calculated by:
(a) Total organic matter
(b) Bio-degradable organic matter
(c) Releasing of oxygen
(d) Consumption of oxygen.
Answer:
(d) Consumption of oxygen.
Question 15.
The technique of biogas production in India developed with the help of these:
(a) Gas Authority of India V
(b) Oil and Natural Gas Aayog
(c) Indian Agricultural Statistics Research Institute.
(d) Indian Oil Corporation.
Answer:
(c) Indian Agricultural Statistics Research Institute.
Question 16.
Free-living fungus Try coderma should be used in:
(a) Kill pests
(b) Biological control of plant diseases.
(c) In control of caterpillar of a butterfly
(d) Formation of Antibiotics.
Answer:
(b) Biological control of plant diseases.
Question 17.
Mycorrhiza does not help the host plant in:
(a) Increasing the phosphorus capturing capacity in host plant
(b) Increasing dryness capturing capacity in host-plant
(c) Increase the immunity of root from pathogen
(d) Increase the immunity from insects in host-plant.
Answer:
(a) Increasing the phosphorus capturing capacity in host plant
2. Fill in the blanks:
- The branch of biology dealing with the structure and modes of existence of microscopic organisms is called ………………………
- The bacteria of …………………….. species is used by making paneer.
- Nitrosomonas and Nitrobacter is ……………………….. bacteria.
- ……………………. bacteria is used in the vinegar industry.
- Pectinase enzyme is made by ……………………….. species.
- Size of microorganism is lesser than ……………………………. mm.
- Curd is made by …………………………… bacteria.
- By the adding of fruit or fruit essence into cheese which is made from milk. The substance is called ………………………..
- The curdled milk which is made from milk is called ………………………
- Antibiotics that are active chiefly against gram-negative bacteria is called ………………………………
Answers:
- Microbiology
- Lactobacillus
- Nitrifying
- Acetobacteraceti
- Clostridium
- 0.1
- Lactobacillus
- Yoghurt
- Raw curded milk
- Polymyxin.
3. Match the Following:
Answers:
- (d)
- (a)
- (b)
- (c)
Answers:
- (c)
- (d)
- (e)
- (a)
- (b)
Answers:
- (d)
- (a)
- (b)
- (c)
4. Answer in One Word/Sentence:
- Name the fish used to control mosquitoes.
- Name the two free-living bacteria found in soil.
- What is called the control of insects and weeds?
- Name symbiotic and non-symbiotic nitrogen-fixing bacteria.
- Write the full name of IPM.
- Give the name of one pesticide.
- How does biofertilizer act as fertilizer? (CBSE2004)
- What is yoghurt?
- What is sufu?
- Name the enzyme which is used to dissolve the blood clot.
- What is interferon?
Answers:
- Gambusia
- Azotobacter, Clostridium
- Pest control and weed control
- Rhizobium, Azotobacter
- Integrated pest management
- D.D.T.
- By nitrogen fixing
- Milk product
- Chinese food
- Streptokinase
- Antiviral protein
Microbes in Human Welfare Very Short Answer Type Questions
Question 1.
Name useful microorganisms.
Answer:
Some useful microorganisms are bacteria, fungi and viruses.
Question 2.
What changes are brought about in milk by LAB?
Answer:
LAB produces acids that coagulate and partially digest the milk proteins.
Question3.
Which products are found by bacteria in dairy farms?
Answer:
Curd, paneer, butter, yoghurt, butter are milk are found in dairy farms in the help of Lactobacillus species and Streptococcus species.
Question 4.
What are prions?
Answer:
Prions are proteinaceous infectious agents
Question 5.
What is microbiology?
Answer:
The branch of science that deals with microorganisms.
Question 6.
Name the fungus which produce these products:
- Cytric acid,
- Vitamin B2
Answer:
Question 7.
What is yoghurt?
Answer:
Yoghurt is a semi-solid sourish food prepared from milk fermented by added bacteria.
Question 8.
Name the organism used for the preparation of Swiss cheese?
Answer:
Propioni bacterium sharmani.
Question 9.
Who discover Penicillin?
Answer:
Alexander Fleming.
Question 10.
What is the scientific name of brewer’s or baker’s yeast? (AI2009)
Answer:
Saccharomyces cerevisiae.
Question 11.
Which organism is used for making citric acid in industries?
Answer:
Aspergillus niger.
Question 12.
Name the free-living nitrogen-fixing bacteria in the soil.
Answer:
Azospirillum and Azotobacter.
Question 13.
What bacteria is found in anaerobic sludge.
Answer:
Methanogene.
Question 14.
What is ladybird?
Answer:
It is an insect which is used as biocontroler for Aphid control.
Question 15.
What is the full form of IPM ?
Answer:
Integrated Pest Management.
Question 16.
What is biological control of Pests?
Answer:
It is the method of controlling pest in agriculture, that relies on natural predation rather than, the introduced elements.
Question 17.
Which mineral is absorbed by mycorhiza, this mineral is not should be absorbed by plant roots?
Answer:
Phosphorus.
Question 18.
Name the microorganism which is changed to milk in curd.
Answer:
Lactobacillus spp.
Question 19.
Which fungi are used in the treatment of plant due to biological control?
Answer:
Trichoderma spp.
Question 20.
Which bacteria is used in swiss paneer?
Answer:
Propionibacterium shermanii.
Question 21.
Which paneer is completed by the growth of fungus?
Answer:
Roquefort cheese.
Question 22.
Name two alcoholic drink which is formed by without distillation.
Answer:
Bear and Wine.
Question 23.
Name two alcoholic drink which are formed by distillation.
Answer:
Whiskey and Rum.
Question 24.
What is the full form of BOD?
Answer:
Biochemical or Biological Oxygen Demand.
Question 25.
Name the bacteria which play an important role in N2 fixation in the soil.
Answer:
Spirullina.
Question 26.
Name an infectious agent which has neither DNA nor RNA.
Answer:
Prion.
Microbes in Human Welfare Short Answer Type Questions
Question 1.
What is paneer ? Give its preparation method.
Answer:
Paneer is a milk product, which has 20-30% protein first filtered and the milk in thin cloth than heat on 60°C at 30 minutes and heat on 75°C at 15 second later it cold till 30°C. Add some quantity of lactic acid bacteria Streptococcus lactis, Streptococcus cremoris and enzyme renin. By this fat and casein protein is detached from milk after 45 minutes this mixture became solid. Now, they are cut into small pieces and boild in hot water, when it starts floating, they are separated and squeezed. Then they areput in salt water for treating. Paneer is now ready.
Question 2.
What is the utilization of Bacteria in agriculture?
Answer:
Uses of Bacteria: Uses of bacteria for agriculture are as follows:
- They increase soil fertility due to the decomposition of dead organisms.
- They increase soil fertility through nitrogen fixation in soil. ‘
- Green-blue algae are used in the form of fertilizers.
- They are balancing the number of mineral salts.
Question 3.
How are the bacteria used in vinegar industry?
Answer:
Fermentation of sugar by yeast in vinegar industry. Due to this manner, wine is prepared. This ethyl alcohol abandoned indirect air for much time now, it is changed in vinegar.
Question 4.
Name five fungi which are given antibiotics.
Answer:
Name the fungi are as follows:
Question 5.
Name five bacteria which produce antibiotics.
Answer:
Name the bacteria are as follows:
Microbes in Human Welfare Long Answer Type Questions
Question 1.
Write a short note Cryprotein and its agricultural use. (CBSE 2006)
Answer:
Cryprotein is a potentially toxic chemical that is produced in pro toxin crystalline endotoxin state by bacterium Bacillus thurigenes. It can be extracted from the bacterium. The protein is also present in spores of the bacterium. The commercial product is called sporein, depel, biostol and thurigenesis. It is sprayed over the crop. As the protein reaches the midgut of the insect.it is converted into the toxic state by alkaline pH and digestive enzyme. The toxic binds to specific receptors present on epithetial cells, creates pores and ruptures the cells causing death of the insects.
There are several types of Cryproteins specific to different types of insects. The gene for cry protein called cry has been incorporated in some crop plants to provide resistance to insect pests. Such genetically modified crop plants are called Bt (after Bacillus thurigenesis) crops, example Bt cotton.
Question 2.
Write economic importance of Fungi.
Answer:
Following are the economic importance of fungi:
- As food: Mushrooms like Agaricus, Lycoperdon, Romaria, Clavasia are used as food. These mushrooms contain about 50% protein. Morchella is also used as food.
- As medicine: Fungi provides various types of antibiotics as for example Penicillin, Griseofulvine, Citrinine, Clavicine, Gliotoxine, etc. Which are used in the treatment of disease.
- The fertility of soil: Many fungi species increase the soil fertility by decomposition of dead organic matter.
- Nitrogen fixation: Many fungus like Rhodotorula increases the soil fertility by nitrogen fixation.
- In the bakery industry: Yeast cells are used in bakery to produce spongy breads.
- In the wine industry: Yeast cells contain the enzyme zymase which ferments sugar into alcohol.
- In the chemical industry: Many fungi species are used in the production of various types of acid like citric acid.
- In the cheese industry: Fungus Penicillium roqueforti is used in the preparation of camembert type of cheese from milk.
Question 3.
Explain the uses and types of viruses.
Answer:
Uses of Viruses:
- As it forms a link between non-living and living thus, it helps us to understand organic evolution.
- Cyanophage (Blue-green algae viruses) are used to destroy blue-green algae grown in different areas.
- Bacteriophages are used as biocides to destroy many harmful bacterias present in a polluted area.
For example, Water of the river Ganga always remain pure and dean in bottles year after year due to presence of bacteriophage’ in it.
Nucleic acids of viruses: Viruses generally contain only one type of nucleic acid DNA or RNA. DNA is found in animal viruses, whereas RNA is found in plant viruses.
Human Immuno Virus (HIV):
It causes AIDS disease in humans. Full form of AIDS is Acquired Immuno Deficiency Syndrome. This virus destroys the immune system of the body, thus, the patient of AIDS suffers from a number of diseases at a time, and at last he dies.
This virus is found surrounded by protein and a ring of RNA is found at the centre. Whole-body of virus is surrounded by a covering of glycoprotein.
Type of Viruses: On the basis of a host infected, viruses are grouped into the following four groups:
- Animal viruses: Viruses which infect animals are called animal viruses. These viruses contain DNA as genetic material.
- Plant viruses: Viruses which infect plants are called plant viruses. These viruses contain RNA as genetic material.
- Cyanophages: Viruses that infect blue-green algae are called cyanophages. These viruses contain RNA as genetic material.
- Bacterial viruses or Bacteriophages: Viruses that infect bacteria are called bacteriophages. They contain DNA as genetic materials.