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BIOLOGY (XII) MICROBES IN HUMAN WELFARE |
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MULTIPLE CHOICE QUESTIONS
(MCQs) |
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1 |
Lactobacillus that sets milk into curd is categorised as (a) cyanobacteria (b) archaebacteria (c) chemosynthetic bacteria (d) heterotrophic bacteria |
1 |
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2 |
Large holes in "Swiss Cheese" are due to (a) Propionibacterium sharmanii (b) Saccharomyces cerevisiae (c) Penicillium chrysogenum (d) Acetobacter aceti |
1 |
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3 |
Which one of the following pairs is not correctly matched? (a) Clostridium butylicum- Butyric acid (b) Trichoderma polysporum -Cyclosporin A (c) Monascus purpureus -Citric acid (d) Streptococcus -Streptokinase |
1 |
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4 |
The bioactive molecule used as an immunosuppressive agent during
organ transplant is (a) tetracyclin (b) cyclosporin A (c) statin (d) streptomycin. |
1 |
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5 |
Conversion of milk to curd improves its nutritional value by
increasing the amount of (a) vitamin D (c) vitamin B12 (b) vitamin A (d) vitamin E |
1 |
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6 |
Which of the following used in the production of beverages? (a) Saccharomyces cerevisiae (b) Streptomyces rimosus (c) Bacillus subtilis (d) Clostridium botulinum |
1 |
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7 |
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. |
1 |
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8 |
Which process is responsible for increasing the percentage of alcohol
in whisky after fermentation? (a) Malting (b) Dilution (c) Distillation (d) Maturation |
1 |
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9 |
Some cyanobacteria in aquatic and terrestrial environment that enrich
the soil by fixing atmospheric nitrogen are (a) Rhizobium and Azotobacter (b) Azospirillum and Glomus (c) Anabaena and Nostoс (d) Azospirillum and Azotobacter |
1 |
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10 |
Which one of the following fixes the atmospheric nitrogen but is not
an autotroph? (a) Oscillatoria (b) Rhizobium (c) Anabaena (d) Nostoс |
1 |
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ASSERTION AND REASON QUESTIONS
(a) Both Assertion (A) and
Reason (R) are true and Reason (R) is the correct explanation of the Assertion
(A). (b) Both Assertion (A) and
Reason (R) are true and Reason (R) is not the correct explanation of the
Assertion (A). (c) Assertion (A) is true, and
Reason (R) is false. (d) Assertion (A) is false,
and Reason (R) True. |
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11 |
Assertion: Baculovirus are
biocontrol agents of genus Nucleopolyhedrovirus. Reason: They are effective
against plant pathogens. |
1 |
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12 |
Assertion: Glomus shows
symbiotic association with higher plants. Reason: Azospirillum and
Azotobacter are free living nitrogen fixing bacteria. |
1 |
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13 |
Assertion: Lactobacillus
bacteria help in curd formation. Reason: Lactobacillus
converts milk sugar (lactose) into lactic acid. |
1 |
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14 |
Assertion: Certain bacteria
are used in sewage treatment plants. Reason: These bacteria degrade
organic matter present in wastewater. |
1 |
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VERY SHORT ANSWER QUESTIONS |
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15 |
"Different varieties of cheese are known by their characteristic
texture, flavour and taste, the specificity coming from the microbes
used." Support this statement with the help of two suitable examples. |
2 |
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16 |
Name the effective biocontrol agents of several plant pathogens
belonging to group of viruses. Also write the ways they support the
environment. |
2 |
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17 |
Why is genus Nucleopolyhedrovirus considered an excellent biocontrol
agent? |
2 |
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18 |
During the production of curd, a small amount of curd is added as a
starter to the fresh milk at a suitable temperature. Explain the changes the
milk undergoes when it sets into curd. |
2 |
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19 |
Name the organism involved in symbiotic nitrogen fixation. What are
the components needed for this purpose? Explain their role. |
2 |
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SHORT ANSWER TYPE QUESTIONS |
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20 |
Describe the contributions of Alexander Fleming, Ernest Chain and
Howard Florey in the field of microbiology. |
3 |
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21 |
Explain the changes that milk undergoes when suitable starter/inoculum
is added to it. How does the end product formed prove to be beneficial for
human health? |
3 |
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22 |
Bottled fruit juices are clearer as compared to those made at home.
Explain. |
3 |
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23 |
What are methanogens? How do they help to generate biogas? |
3 |
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24 |
Choose any three microbes, from the following which are suited for
organic farming which is in great demand these days for various reasons.
Mention one application of each one chosen. Mycorrhiza Monascus, Anabaena,
Rhizobium Methanobacterium, Trichoderma. |
3 |
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25 |
(a) Why do farmers prefer biofertilisers over chemical fertilisers
these days? Explain. (b) How do Anabaena and mycorrhiza act as biofertilisers? |
3 |
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26 |
Explain the change fresh milk undergoes when a small amount of curd
as starter is added to it and kept at suitable temperature. |
3 |
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LONG ANSWER TYPE QUESTIONS |
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27 |
(a) Name the category of microbes occurring naturally in sewage and
making it less polluted during the treatment. (b) Explain the different steps involved in the secondary treatment of
sewage. |
5 |
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28 |
Prior to sowing rice, a legume crop was cultivated and ploughed back
in the field, why? Explain. |
5 |
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29 |
a) Explain the process of sewage water treatment before it can be
discharged into natural water bodies. (b) Why is this treatment essential? |
5 |
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30 |
(a) Microbes can be used as source of energy. Give (b) Give any four differences between primary and secondary sludge. |
5 |
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31 |
What are biofertilisers? Describe their role in agriculture. Why are
they preferred to chemical fertilisers? |
5 |
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32 |
Secondary treatment of the sewage is also called biological
treatment. Justify this statement and explain the process. |
5 |
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33 |
(a) Write the scientific name of methanogen bacteria. Where are these
bacteria generally found? Explain their role in biogas production. (b) Name the components of biogas. |
5 |
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CASE BASED STUDY QUESTIONS |
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34 |
Read the passage carefully and answer the following questions: A dairy company noticed that curd prepared in certain batches had a
better texture and taste. After investigation, they found that the milk used
in these batches contained a higher population of Lactobacillus bacteria.
These bacteria convert lactose (milk sugar) into lactic acid, which causes
coagulation of milk. The company also uses yeast (Saccharomyces cerevisiae)
in its bakery section to produce soft and fluffy bread. The yeast produces
CO₂ during fermentation, causing the dough to rise. 1. Which microorganism is responsible for the formation of curd? 2. What change does Lactobacillus bring about in milk? 3. Name the type of fermentation carried out by yeast in
bread-making. 4. What gas is released by yeast that helps the dough to rise? 5. State one industrial product made using microbes. |
4 |
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35 |
Read the passage carefully and answer the following questions: During a science exhibition, a student explains that antibiotics like
penicillin are produced using fungi. Penicillin was discovered by Alexander
Fleming from Penicillium notatum. Antibiotics are used to treat bacterial
infections but are ineffective against viral diseases. Overuse or misuse of
antibiotics can lead to antibiotic resistance, where bacteria stop responding
to medicines. 1. Penicillin is produced from which organism? 2. Penicillin is effective against which type of infections? 3. Why should antibiotics not be used for viral infections? 4. Who discovered penicillin? 5. What is antibiotic resistance? |
4 |
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36 |
Read the passage carefully and answer the following questions: A farmer wants to increase crop productivity without using chemical
fertilizers. An agricultural scientist suggests using biofertilizers such as
Rhizobium, Azotobacter, Azospirillum, and blue-green algae like Anabaena.
These microbes naturally fix atmospheric nitrogen into ammonia, thereby
enriching the soil. Biofertilizers also improve soil texture and
water-holding capacity and are eco-friendly. 1. Why are biofertilizers considered eco-friendly? 2. Name any two nitrogen-fixing microorganisms. 3. In which plants does Rhizobium live symbiotically? 4. How do BGA (Blue-Green Algae) increase soil fertility? 5. Biofertilizers reduce the need for which type of fertilizers? |
4 |
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37 |
Read the passage carefully and answer the following questions: A city’s sewage treatment plant (STP) operates in two main stages:
primary and secondary treatment. In the secondary treatment, a large aeration
tank is used. When sewage enters the tank, air is pumped to promote the
growth of aerobic microbes. These microbes consume organic matter, forming
flocs. After this, the water is passed to the settling tank where microbes
settle as activated sludge. A portion of the sludge is used to inoculate new
sewage, while the rest goes to anaerobic digesters to produce biogas. 1. What is the purpose of aerating the sewage in the aeration tank? 2. What are flocs made of? 3. What happens to activated sludge after sedimentation? 4. Which type of microbes form biogas in anaerobic digesters? 5. Give one use of biogas. |
4 |
FOLLOW THE INSTRUCTIONS FOR DOWNLOAD THIS ASSIGNMENT:
1. SEARCH WWW.SCIENCEARENA.IN
2. OPEN EDUCATION AND RESOURCES IN MENU BAR.
3. SINGLE CLICK DOWNLOAD AVAILABLE IN DOWNLAOD SECTION.
https://www.sciencearena.in/p/education-resources.html