Read and download free pdf of CBSE Class 12 Biology Microbes In Human Welfare Worksheet Set A. Download printable Biology Class 12 Worksheets in pdf format, CBSE Class 12 Biology Chapter 10 Microbes In Human Welfare Worksheet has been prepared as per the latest syllabus and exam pattern issued by CBSE, NCERT and KVS. Also download free pdf Biology Class 12 Assignments and practice them daily to get better marks in tests and exams for Class 12. Free chapter wise worksheets with answers have been designed by Class 12 teachers as per latest examination pattern
Chapter 10 Microbes In Human Welfare Biology Worksheet for Class 12
Class 12 Biology students should refer to the following printable worksheet in Pdf in Class 12. This test paper with questions and solutions for Class 12 Biology will be very useful for tests and exams and help you to score better marks
Class 12 Biology Chapter 10 Microbes In Human Welfare Worksheet Pdf
Microbes in Human Welfare
MULTIPLE CHOICE QUESTIONS
Question. Which of the following antibiotic was discovered by Alexander Flemming ?
(a) Streptomycin
(b) Tetracycline
(c) Penicillin
(d) Terramycin
Answer: C
Question. What would happen if oxygen availability to activated sludge flocs is reduced?
(a) It will slow down the rate of degradation of organic matter.
(b) The centre of flocs will become anoxic, which would cause death of bacteria and eventually breakage of flocs.
(c) Flocs would increase in size as anaerobic bacteria would grow around flocs.
(d) Protozoa would grow in large numbers.
Answer: B
Question. Which one of the following statement regarding BOD is true?
(a) The greater the BOD of waste water, more is its polluting potential.
(b) The greater the BOD of waste water, less is its polluting potential.
(c) The lesser the BOD of waste water, more is its polluting potential.
(d) The lesser the BOD of waste water, less is its polluting potential.
Answer: A
Question. Which one of the following pairs is correctly matched?
(a) Rhizobium - Parasite in the roots of leguminous plants.
(b) Mycorrhizae - Mineral uptake from soil.
(c) Yeast - Production of biogas.
(d) Myxomycetes - The ringworm diseases.
Answer: B
Question. The bacteria Pseudomonas is useful because of its ability to
(a) transfer genes from one plant to another.
(b) decompose a variety of organic compounds.
(c) fix atmospheric nitrogen in the soil.
(d) produce a wide variety of antibiotics.
Answer: B
ASSERTION REASON QUESTIONS
Directions : These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following five responses.
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
(e) If the Assertion is incorrect but the Reason is correct.
Question. Assertion : Leguminous plants are nitrogen fixers.
Reason : Leguminous plants have Rhizobium in their root nodules.
Answer: A
Question. Assertion : Nitrogen-fixing enzyme in legume root nodules function at low oxygen concentration.
Reason : Low oxygen concentration is provided by leghaemoglobin.
Answer: A
Very Short Answer Type Questions
Question. Why are blue-green algae not popular as biofertilisers?
Answer : Blue-green algae add organic matter to the soil and increase its fertility still these are not popular as biofertilisers. This is due to several constraints that limit the application or implementation of the biofertiliser technology. The constraints may be environmental, technological, infrastructural, financial, unawareness, quality, marketing etc.
Question. Which species of Penicillium produces Roquefort cheese?
Answer : Roquefort cheese is formed by ripening of cheese with the fungi Penicillium roqueforti for a particular flavour.
Question. Name the states involved in Ganga Action Plan.
Answer : Ganga runs from Gangotri in the Himalayas to Ganga Sagar in the Bay of Bengal. The Ganga Action Plan (GAP) was a program launched in April 1986 in order to reduce the pollution load on the River Ganga. The states involved in Ganga Action Plan are— Uttaranchal, UP, Bihar, West Bengal and Jharkhand.
Question. Name any two industrially important enzymes.
Answer : (i) Lipases are used in detergent formulations and are helpful in removing oily stains from the laundry. (ii) Pectinases and proteases that are used as clarifying agents in making commercial fruit and vegetable juices.
Question. Name an immune immunosupressive agent?
Answer : Cyclosporin-A, produced by the fungus Trichoderma polysporum is used as an immunosupressive agent in organ transplant patients.
Question. Given an example of a rod-shaped virus.
Answer : Tobacco mosaic virus is a rod-shaped virus. This is the first plant virus to be discovered.
Question. What would happen if our intestine harbours microbial flora exactly similar to that found in the rumen of cattle?
Answer : If our intestine harbors microbial flora exactly similar to that found in the rumen of cattle, we would be able to digest the cellulose present in our foods because the microbes present in the rumen (a part of stomach) of cattle, collectively called methanogens, are capable of digesting cellulose as they have cellulase enzyme.
Question. Give any two microbes that are useful in biotechnology.
Answer : Two microbes that are useful in biotechnology are (i) Bacillus thuringiensis a gene isolated from this bacterium is introduced in cotton plants to make them able to kill butterfly caterpillars. (ii) Escherichia coli is a bacterium that is used in many biotechnology procedures. Their plasmid is used as vector to introduce foreign DNA segment in desired organisms.
Question. What is the source organism for Eco RI, restriction endonuclease?
Answer : Escherichia coli strain RY 13 is the source organism for Eco RI.
Question. Name any genetically modified crop.
Answer : Bt cotton is a genetically modified plant that has been modified to resist attack by insect pests e.g., cotton ball worm). These are developed by introducing a gene from Bacillus thuringiensis which produces toxin is plants which is lethat to insects.
Question. What is the group of bacteria found in both the rumen of cattle and sludge of sewage treatment?
Answer : Methanogens (Methanobacterium), anaerobically break down cellulosic material to produce CO2 and H2, and are found in (i) Anaerobic sludge in sewage treatment plants. (ii) Rumen (a part of stomach) of cattles, thus providing nutrition to cattles.
Question. Name a microbe used for the production of swiss cheese.
Answer : Cheese is formed by partial degradation of milk by different microorganisms. Swiss cheese is formed by the bacterium Propionibacterium sharmanii. Its characteristic feature is formation of large holes due to production of large amount of CO2
Question. Large holes in ‘Swiss-Cheese’ are due to which micro-organism.
Answer : Large holes in ‘Swiss-Cheese’ are due to Propionibacterium shermanii.
Question. What are ‘flocs’, formed during secondary treatment of sewage ?
Answer : Masses of bacteria associated with fungal filament (to form mesh like structure).
Question. Name the organism which forms symbiotic association with plants and helps them in their nutrition.
Answer : Glomus, is a genus of arbuscular mycorrhizal fungi which form a symbiotic relationship with plant roots.
Question. Name any two free nitrogen fixing bacteria.
Answer : Azotobacter and Azospirillum.
Short Answer Type Questions
Question. What roles do enzymes play in detergents that we use for washing clothes? Are these enzymes produced from some unique microorganisms?
Answer : Enzymes like lipases are used in detergent which formulations, cause breakdown of oils and thus help in removing oily and greasy stains from the clothes in laundry. These are obtained from Candida lipolytica and Geotrichum candidum.
Question. What is the chemical nature of biogas. Name an organism which is involved in biogas production?
Answer : The chemical nature of biogas is CH4, CO2, H2 and a trace amount of H S 2 Methanobacteria, a type of methanogen is employed for biogas production.
Question. How do microbes reduces the environmental degradation causes by chemicals?
Answer : Chemicals from fertilisers and pesticides are highly toxic to human beings and animals alike, and have been polluting our environment. To reduce the environmental degradation caused by chemicals, microbes can be used both as fertilisers and pesticides and can be called biofertilisers and biopesticides, respectively. Microbes are used as biofertilisers to enrich the soil nutrients, e.g., Rhizobium, Azotobacter, Azospirillum, etc., which can fix atmospheric nitrogen in the soil. Bacillus thuringiensis bacteria act as biopesticides to control the growth of insect pests. Trichoderma, fungal species, is effective bicontrol agent of several plant pathogens. Baculovirus used as biological control agents in genus Nucleopolyhedrovirus are excellent for species-specific, narrow spectrum insecticidal applications.
Question. Why are flocs important in biological treatment of waste water?
Answer : Flocs are masses of bacteria associated with fungal filaments that form mesh like structures. These are important in biological treatment of waste water, as they help in digestion of organic matter, remove pathogens and release nutrients in the sewage effluent.
Question. How has the bacterium Bacillus thuringiensis helped us in controlling caterpillars of insect pests?
Answer : Bacillus thuringiensis produces an are endotoxin which, when ingested and released in the gut of the larvae of insect pest disrupts the insect gut lining thereby killing them.
Question. What is a broad spectrum antibiotic? Name one such antibiotic.
Answer : A broad spectrum antibiotic is one which can inhibit the growth of both Gram positive and Gram negative bacteria e.g.,Tetracyclines, phenicols, fluoroquinolones, third-generation and fourth-generation antibiotivcs is cephalosporins.
Question. What are viruses parasitising bacteria called? Draw a well labelled diagram of the same.
Answer : Viruses parasitising bacteria are called bacteriophages. These viruses do not actually eat bacteria. They infect and replicate within the bacteria.
Question. “Large scale cultivation of Spirulina is highly advantageous for human population.”
Explain giving two reasons.
Answer : Source of good protein, fats, carbohydrates, minerals and vitamins for undernourished humans and animal population, reduce environmental pollution / can be grown in wastewater / molasses / straw / animal manure, easy to cultivate.
Question. Spirulina is a rich source of proteins. Mention the two ways by which large scale culturing of these microbes is possible.
Answer : Spirulina is a source of food rich in protein, minerals, fats, carbohydrates and vitamins. It can grow on wastewater from potato processing plants, straw, molasses, animal manure and even sewage, so it also reduces water pollution.
Question. Name a genus of baculovirus. Why are they considered good biocontrol agents ?
OR
Name the genus to which baculoviruses belong. Describe their role in the integrated pest management programmes.
Answer : Nucleopolyhedrovirus Species specific, narrow spectrum insecticidal application, no negative impact on non-target organisms.
Question. Describe the contributions of Alexander Fleming, Ernest Chain and Howard Florey in the field of microbiology.
Answer : Alexander Fleming while working on Staphylococci bacteria, once observed a mould growing in one of his unwashed culture plates around which Staphylococci could not grow. He found out that it was due to a chemical produced by the mould and he named it penicillin after the mould Pencillium notatum. Later, Ernest Chain and Howard Florey made its full potential effective antibiotic.
Question. List the events that lead to biogas production from wastewater whose BOD has been reduced significantly.
Answer : Sedimentation of flocs to form activated sludge, sludge pumped to anaerobic sludge digester, growth of anaerobic bacteria, digestion of sludge by bacteria to release biogas.
Question. Mention a product of human welfare obtained with the help of each one of the following microbes :
(i) LAB
(ii) Saccharomyces cerevisiae
(iii) Propionibacterium shermanii
(iv) Aspergillus niger
Answer : (i) Milk to curd
(ii) Bread / ethanol / alcoholic drinks / whisky / brandy / beer/ rum
(iii) Swiss cheese
(iv) Citric acid
Question. Why does the insecticidal protein produced by Bacillus thuringiensis not kill the bacterium, but kills the cotton bollworm? Explain.
Answer : The Bt toxin protein exists as inactive protoxins, it becomes active due to the alkaline pH of the gut of cotton bollworm.
Question. Name a bioactive molecule, its source organism and the purpose for which it is given to organ transplant patients.
Answer : Cyclosporin A.
Source – Trichoderma polysporum.
Purpose – Immunosuppressive agent.
Question. How does the application of the fungal genus, Glomus, to the agricultural farm increase the farm output ?
Answer : Glomus forms mycorrhizal association, absorbs phosphorus, provide resistance to root borne pathogens, enhanced to tolerate salinity / drought.
Long Answer Type Questions
Question. Draw a diagrammatic sketch of biogas plant and label its various components given below gas holder, sludge chamber, digester, dung + water chamber.
Answer : The raw material for biogas production is excreta (dung) of cattle. The biogas plant has a concrete tank (10-15 feet deep) in which bio-wastes and slurry of dung is collected. (Image 195) The tank has a floating cover which rises on production of gas in the tank. Methanobacterium in the dung act on the bio-wastes to produce biogas. The gas produced is supplied to nearby houses by an outlet. Through another outlet, the spent slurry is removed to be used as fertiliser. Biogas is used as fuel for cooking and lighting.
Question. Describe the main ideas behind the biological control of pests and diseases.
Answer : It’s a natural and eco-friendly concept. If employs the use of organisms to control the population of pathogens and pests in an ecosystem. Classical examples are Trichoderma which is antagonist, i.e., against many soil borne plant pathogens. Similarly, Penicillium inhibits the growth of Staphylococcus and therefore has been successfully used in the production of penicillin antibiotic to control many human bacterial pathogens. Bacillus thuringiensis acts as biopesticide to control insect. Baculovirus used as biological control agents in genus Nucleo-polyhedrovirus are excellent for species-specific-narrow spectrum insecticidal application. The overall biological control of pest is considered much more beneficial in an ecological sensitive area.
Question. Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of wastewaters rich in organic matter. Discuss.
Answer : Aerobic degradation is more important as naturally occurring aerobic and facultative microbes (bacteria, fungi, Protozoa and others) in the waste water can rapidly oxidise soluble organic and nitrogenous compounds. Mechanical addition of oxygen makes the process faster and most of the pathogenic content of the effluent is removed.
Question. (a) Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution. (b) Ganga has recently been declared the national river. Discuss, the implication with respect to pollution of this river.
Answer : (a) Prior to year 1985, only few cities and towns had sewage treatment plants. Most of the sewage water of urban as well as rural areas was discharged directly into rivers resulting in their pollution. Importance of microbial treatment of sewage was then realised and more sewage treatment plants were established. Still, they are not sufficient due to increasing urbanisation and production of much larger quantities of sewage as compared to earlier days. Realising the importance of microbes in pollution control, the Ministry of Environment and forests has initiated development of sewage treatment plants under the National River Conservation Authority. e.g., Ganga Action Plan (GAP) and Yamuna Action Plan (YAP) to save these major rivers of our country from pollution.
(b) The Ganga Action Plan (GAP) was a program launched in April, 1986 in order to reduce the pollution load on the river. A steering committee of the National River Conservation Authority reviewed the progress of the GAP and necessary correction. Scientists and religious leaders have speculated on the causes of the river’s apparent self-purification effect, in which water-borne diseases such as dysentery and cholera are eliminated by killing thin caused organisms. Thus preventing large-scale epidemics. Some studies have reported that the river retains more oxygen than is typical for comparable rivers; this could be a factor leading to fewer disease agents being present in the water. National River Ganga Basin Authority (NRGBA) was established by the Central Government of India, on 20th February 2009 Under Section 3(3) of The Environment Protection Act, 1986. It also declared Ganges as the National, river of India.
Question. (a) What would happen if a large volume of untreated sewage is discharged into a river? (b) In what way anaerobic sludge diagestion is important in sewage treatments?
Answer : (a) If untreated sewage is discharged directly into rivers it will lead to serious pollution of the waters with organic matter and pathogenic bacteria, Protozoa and many other diseaser. This water, if used, will cause outbreaks of water borne diseases. (b) In anaerobic sludge digestion, anaerobic bacteria, digest the aerobic bacteria and the fungi in the sludge and the remaining organic matter. During this digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. These gases (biogas) can be used as source of energy as it is inflammable.
Question. Which type of food would have lactic acid bacteria? Discuss their useful application.
Answer : The most common food item that are curd, and yoghurt contain Lactic Acid Bacteria (LAB) of Lactobacillus species. Curd is formed by adding a small amount of curd to milk, which acts as a starter. Microbes present in starter multiply at suitable temperature and convert milk into curd. Acids released by LAB during the growth coagulate and partially digest milk protein, casein thus increases the digestibility of milk protein. Application of LAB (i) Improves nutritional quality of milk by increasing vitamin-B12. (ii) Checks disease-causing microbes in stomach.
Please click on below link to download CBSE Class 12 Biology Microbes In Human Welfare Worksheet Set A
CBSE Class 12 Biology Evolution Question Bank |
CBSE Class 12 Biology Evolution Worksheet Set A |
CBSE Class 12 Biology Evolution Worksheet Set B |
CBSE Class 12 Biology Biotechnology And Its Application Question Bank |
CBSE Class 12 Biology Biotechnology and Its Applications Worksheet Set A |
CBSE Class 12 Biology Ecosystem Question Bank |
CBSE Class 12 Biology Ecosystem Worksheet Set A |
CBSE Class 12 Biology Ecosystem Worksheet Set B |
More Study Material
CBSE Class 12 Biology Chapter 10 Microbes In Human Welfare Worksheet
The above practice worksheet for Chapter 10 Microbes In Human Welfare has been designed as per the current syllabus for Class 12 Biology released by CBSE. Students studying in Class 12 can easily download in Pdf format and practice the questions and answers given in the above practice worksheet for Class 12 Biology on a daily basis. All the latest practice worksheets with solutions have been developed for Biology by referring to the most important and regularly asked topics that the students should learn and practice to get better scores in their examinations. Studiestoday is the best portal for Printable Worksheets for Class 12 Biology students to get all the latest study material free of cost.
Worksheet for Biology CBSE Class 12 Chapter 10 Microbes In Human Welfare
Teachers of studiestoday have referred to the NCERT book for Class 12 Biology to develop the Biology Class 12 worksheet. If you download the practice worksheet for the above chapter daily, you will get better scores in Class 12 exams this year as you will have stronger concepts. Daily questions practice of Biology printable worksheet and its study material will help students to have a stronger understanding of all concepts and also make them experts on all scoring topics. You can easily download and save all revision Worksheets for Class 12 Biology also from www.studiestoday.com without paying anything in Pdf format. After solving the questions given in the practice sheet which have been developed as per the latest course books also refer to the NCERT solutions for Class 12 Biology designed by our teachers
Chapter 10 Microbes In Human Welfare worksheet Biology CBSE Class 12
All practice paper sheet given above for Class 12 Biology have been made as per the latest syllabus and books issued for the current academic year. The students of Class 12 can be assured that the answers have been also provided by our teachers for all test paper of Biology so that you are able to solve the problems and then compare your answers with the solutions provided by us. We have also provided a lot of MCQ questions for Class 12 Biology in the worksheet so that you can solve questions relating to all topics given in each chapter. All study material for Class 12 Biology students have been given on studiestoday.
Chapter 10 Microbes In Human Welfare CBSE Class 12 Biology Worksheet
Regular printable worksheet practice helps to gain more practice in solving questions to obtain a more comprehensive understanding of Chapter 10 Microbes In Human Welfare concepts. Practice worksheets play an important role in developing an understanding of Chapter 10 Microbes In Human Welfare in CBSE Class 12. Students can download and save or print all the printable worksheets, assignments, and practice sheets of the above chapter in Class 12 Biology in Pdf format from studiestoday. You can print or read them online on your computer or mobile or any other device. After solving these you should also refer to Class 12 Biology MCQ Test for the same chapter.
Worksheet for CBSE Biology Class 12 Chapter 10 Microbes In Human Welfare
CBSE Class 12 Biology best textbooks have been used for writing the problems given in the above worksheet. If you have tests coming up then you should revise all concepts relating to Chapter 10 Microbes In Human Welfare and then take out a print of the above practice sheet and attempt all problems. We have also provided a lot of other Worksheets for Class 12 Biology which you can use to further make yourself better in Biology
You can download the CBSE Practice worksheets for Class 12 Biology Chapter 10 Microbes In Human Welfare for the latest session from StudiesToday.com
Yes, you can click on the links above and download chapter-wise Practice worksheets in PDFs for Class 12 for Biology Chapter 10 Microbes In Human Welfare
Yes, the Practice worksheets issued for Chapter 10 Microbes In Human Welfare Class 12 Biology have been made available here for the latest academic session
You can easily access the links above and download the Class 12 Practice worksheets Biology for Chapter 10 Microbes In Human Welfare
There is no charge for the Practice worksheets for Class 12 CBSE Biology Chapter 10 Microbes In Human Welfare you can download everything free
Regular revision of practice worksheets given on studiestoday for Class 12 subject Biology Chapter 10 Microbes In Human Welfare can help you to score better marks in exams
Yes, studiestoday.com provides all the latest Class 12 Biology Chapter 10 Microbes In Human Welfare test practice sheets with answers based on the latest books for the current academic session
Yes, studiestoday provides worksheets in Pdf for Chapter 10 Microbes In Human Welfare Class 12 Biology in mobile-friendly format and can be accessed on smartphones and tablets.
Yes, practice worksheets for Class 12 Biology Chapter 10 Microbes In Human Welfare are available in multiple languages, including English, Hindi