Read and download free pdf of CBSE Class 12 Biology Microbes In Human Welfare Worksheet Set B. Students and teachers of Class 12 Biology can get free printable Worksheets for Class 12 Biology in PDF format prepared as per the latest syllabus and examination pattern in your schools. Standard 12 students should practice questions and answers given here for Biology in Grade 12 which will help them to improve your knowledge of all important chapters and its topics. Students should also download free pdf of Class 12 Biology Worksheets prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this academic year and solve important problems provided here with solutions on daily basis to get more score in school exams and tests
CBSE Class 12 Biology Microbes in Human Welfare (2). CBSE issues sample papers every year for students for class 12 board exams. Students should solve the CBSE issued sample papers to understand the pattern of the question paper which will come in class 12 board exams this year. The sample papers have been provided with marking scheme. It’s always recommended to practice as many CBSE sample papers as possible before the board examinations. Sample papers should be always practiced in examination condition at home or school and the student should show the answers to teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.
ONE MARK QUESTION
1 Name the group of organisms and the substrate they act on to produce biogas.
2 What is the role of bacterium in the production of Swiss cheese?
3 How can small amount of curd added to fresh milk convert it to curd?
4 write the scientific name of baker’s yeast.
TWO MARK QUESTIONS
5 What are baculoviruses? Write their significance in agriculture.
7 Mention the functions of LAB that are useful to man.
8 Name any four industrial products that employ microbes in their production.
9 Name any two alcoholic bewerages produced in each of the following ways:
a) With distillation
b) Without distillation
10 Mention any four diseases that can be treated by antibiotics.
3 MARK QUESTIONS
11 Name the three types of micro organisms acting as biofertilizers. How do they enrich the soil fertility?
12 Name any three organic acids and the microbes producing them.
13 Describe biogas plant.
14 Write the names of microbes from which Cyclosporin A, Statin and streptokinase obtained. Also write their importance.
5 MARK QUESTIONS
15 Dscribe the treatment of sewage before it is discharged into a water body like a river.
16 What are biofertilizers? Name the categories of organisms used as biofertilizers with an example for each.
Ques. Which bacteria is utilized in gobar gas plant?
(b) Nitrifying bacteria
(c) Ammonifying bacteria
(d) Denitrifying bacteria
Ques. Gobar gas contains mainly
(a) CO2 + H2 (b) CO2 + H2O
(c) CH4 only (d) CH4 + CO2.
Ques. Which of the following can be used as a biocontrol agent in the treatment of plant disease?
(a) Lactobacillus (b) Trichoderma
(c) Chlorella (d) Anabaena
Ques. Select the correct group of biocontrol agents.
(a) Nostoc, Azospirillium, Nucleopolyhedrovirus
(b) Bacillus thuringiensis, Tobacco mosaic virus, Aphids
(c) Trichoderma, Baculovirus, Bacillus thuringiensis
(d) Oscillatoria, Rhizobium, Trichoderma
Ques. A biocontrol agent to be a part of an integrated pest management should be
(a) species-specific and symbiotic
(b) free living and broad spectrum
(c) narrow spectrum and symbiotic
(d) species-specific and inactive on non-target organisms.
Ques. Microbe used for biocontrol of pest butterfly caterpillars is
(a) Saccharomyces cerevisiae
(b) Bacillus thuringiensis
(c) Streptococcus sp.
(d) Trichoderma sp.
Ques. Which one of the following is an example of carrying out biological control of pests/diseases using microbes?
(a) Trichoderma sp. against certain plant pathogens.
(b) Nucleopolyhedrovirus against white rust in Brassica.
(c) Bt-cotton to increase cotton yield.
(d) Lady bird beetle against aphids in mustard.
Ques. A common biocontrol agent for the control of plant diseases is
(b) Bacillus thuringiensis
Ques. Which of the following is not used as a biopesticide?
(a) Trichoderma harzianum
(b) Nucleopolyhedrovirus (NPV)
(c) Xanthomonas campestris
(d) Bacillus thuringiensis
Ques. Trichoderma harzianum has proved a useful microorganism for
(a) gene transfer in higher plants
(b) biological control of soil-borne plant pathogens
(c) bioremediation of contaminated soils
(d) reclamation of wastelands.
Ques. Which one of the following proved effective for biological control of nematodal diseases in plants?
(a) Gliocladium virens
(b) Paecilomyces lilacinus
(c) Pisolithus tinctorius
(d) Pseudomonas cepacia
Ques. A genetically engineered microorganism used successfully in bioremediation of oil spills is a species of
(a) Trichoderma (b) Xanthomonas
(c) Bacillus (d) Pseudomonas.
Ques. Biological control component is central to advanced agricultural production. Which of the following is used as a third eneration pesticide?
(a) Insect repellants
(b) Organophosphate and carbamates
Ques. Cochineal insects have proved very useful for
(a) cactus prevention (b) Eichhornia prevention
(c) weeds control (d) Parthenium control.
Ques. When a natural predator (living being) is applied on the other pathogen organism to control them, this process is called
(a) artificial control (b) confusion technique
(c) biological control (d) genetic engineering.
Ques. The rotenone is
(a) a natural herbicide (b) a natural insecticide
(c) an insect hormone (d) a bioherbicide.
Ques. One of the major difficulties in the biological control of insect pest is that
(a) the method is less effective as compared with the use of insecticides
(b) the practical difficulty of introducing the predator to specific areas
(c) the predator develops a preference to other diets and may itself become a pest
(d) the predator does not always survive when transferred to a new environment.
Ques. Biological control of agricultural pests, unlike chemical control, is
(a) self perpetuating (b) polluting
(c) very expensive (d) toxic.
Ques. Select the mismatch.
(a) Rhodospirillum – Mycorrhiza
(b) Anabaena – Nitrogen fixer
(c) Rhizobium – Alfalfa
(d) Frankia – Alnus
Ques. A nitrogen-fixing microbe associated with Azolla in rice fields is
(a) Spirulina (b) Anabaena
(c) Frankia (d) Tolypothrix.
Ques. Which one of the following microbes forms symbiotic association with plants and helps them in their nutrition?
(a) Azotobacter (b) Aspergillus
(c) Glomus (d) Trichoderma
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