Microbes in Human Welfare | Class 12 | Sample Questions and Answers

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MICROBES IN HUMAN WELFARE

QUESTIONS

1 Score Questions

1.    The bacteria that can convert milk to curd is

a. Acetobacter aceti
b. Lactobacillus
c. Clostridium butylicum
d. Streptococcus

2.    Swiss cheese has large holes due to the production of CO2 by …………………
3.    The chemical substances produced by some microbes and can kill the pathogens are known as …………….
4.    Note the relationship between first two words and fill up the fourth place.
Saccharomyces cerevisiae: Ethanol
Clostridium butylicum: …………….
5.    Name 2 enzymes used to clarify bottled juices.
6.    Cyclosporin A is produced by................
a. Aspergillus niger
b. Clostridium tetani
c. Trichoderma polysporum
d. Acetobacter aceti
7.    Penicillin is the first antibiotic discovered by …………….
8.    The main ingredient of Biogas is
a. Ethane
b. Hydrogen sulphide
c. Methane
d. Carbon dioxide
9.    Select a bio-control agent from the given microbe.
a. Trichoderma 
b. Rhinovirus
c. Saccharomyces 
d. Streptococcus
10.    The nitrogen fixing symbiotic bacteria in root nodules of leguminous plants is
a. Azotobacter 
b. Azospirillum
c. Clostridium 
d. Rhizobium

2 Score Questions

11.    Lactic acid bacteria are beneficial microbe for our health. Justify this statement pointing two examples.
12.    Match the column B & C with respect to A.

A

B

C

Cyanobacteria

Biocontrol

Antibiotic

Baculoviruses

Penicillin

Biofertilizer

Penicillium notatum

Anabaena

IPM programme

13.    Complete the table given below:

Bioactive molecule

Source

Medical importance

a

Streptococcus

Removes clots from blood vessels

Cyclosporine-A

b

c

d

Monascus purpureus

Blood cholesterol lowering agent

14.    Many microbes are acid producers. Name any two such microbes and acids produced by them.

15.    “BOD is an index of water pollution”
a. Do you agree with this statement? Justify.
b. Expand BOD.

16.    BOD of some water sample is given below.
Sample 1: 200mg/L
Sample 2: 80mg/L
Sample 3: 300mg/L
Sample 4: 25mg/L

a. Which of above water sample is most polluted?
b. What is meant by flocs? Mention its role in sewage treatment.

17.    Expand: (a) IARI (b) KVIC.
18.    Microbes can be considered as a source of energy. Substantiate with an example.
19.    Match the following:

Methanogens

Aspergillus niger

Flocs

Aerobic microbes

Citric acid

Anaerobic microbes

Baker’s yeast

Lactobacillus

 

Saccharomyces cerevisiae
 
20.   (a) What are the advantages of biofertilizers over chemical fertilizers?
        (b) Give two examples for biofertilizer.

ANSWERS

1.    (b) Lactobacillus
2.    Propionibacterium sharmani.
3.    Antibiotics
4.    Butyric acid
5.    Pectinases & Proteases.
6.    (c) Trichoderma polysporum
7.    Alexander Fleming
8.    (c) Methane
9.    (a) Trichoderma
10.    (d) Rhizobium
11.    Lactic acid bacteria (LAB) increase vitamin B12 in curd. Also, it helps to check pathogens in stomach.

12.    

A

B

C

Cyanobacteria

Anabaena

Biofertilizer

Baculoviruses

Biocontrol

IPM programme

Penicillium notatum

Penicillin

Antibiotic

13.
a. Streptokinase
b. Trichoderma polysporum
c. Immunosuppressive agent
d. Statins

14.    Aspergillus niger (a fungus) : Citric acid.
         Acetobacter aceti (a bacterium) : Acetic acid.

15.    
a. Yes. It is a measure of organic matter present in the water. Greater BOD means water is more polluted.
b. Biochemical Oxygen Demand.

16.
a. Sample 3.
b. Flocs are aerobic bacteria associated with fungal filaments to form mesh-like structures. They consume the organic matter in the effluent reducing its BOD.

17.
a) Indian Agricultural Research Institute.
b) Khadi and Village Industries Commission.

18.    This statement is true. Because microbes such as Methanogens can be used to produce biogas. Biogas is an important energy source.

19.

Methanogens

Anaerobic microbes

Flocs

Aerobic microbes

Citric acid

Aspergillus niger

Baker’s yeast

Saccharomyces cerevisiae

20.    (a) Chemical fertilizers are harmful to the soil and beneficial organisms. Biofertilizers have no such problems. They can maintain the nature and quality of soil.
        (b) Rhizobium, Mycorrhiza.

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