2nd PUC Biology Question Bank Chapter 10 Microbes in Human Welfare

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Karnataka 2nd PUC Biology Question Bank Chapter 10 Microbes in Human Welfare

2nd PUC Biology 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 – Contains Lactic Acid Bacteria Lactobacillus acidophilus).

Question 2.
Give examples to prove that microbes release gases during metabolism.
Answer:
Dough of dosa and idli is fermented by bacteria while 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:
Curd
Uses:-

• Lactic acid bacteria (LAB) convert milk into curd by producing lactose. Converts sugar lactose into acid which converts casein in milk to curd.
• Removes lactose, produce Vitamin B₁₂ and checks growth of putrefying bacteria as well as harmful microbes.

Question 4.
Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve 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:
Microbes have been a source of antibiotics. Antibiotics have been used successfully against pathogenic bacteria. E.g.: streptomycin (str. griseus), erythromycin
(str. erythreus),Bacitracin (Bacillus licheni – formis)

Question 6.
Name any two species of fungus, which are used in the production of the antibiotics.
Answer:

• Penicillin – Penicillin chrysogenum
• Griseofulvin – Penicillin griseofulvin
• Fumagillin – Aspergillus puniyatus
• Cephalosporin – Cephalosporium acremonium.

Question 7.
What is sewage? In which way can sewage be harmful to us?
Answer:
Sewage/municipal waste water is human excreta and other organic wastes containing large number of pathogenic microbes and harmful chemicals. It is harmful to us because

• Source of various water
• Causes eutrophication of water
• Produces scum and sludge, bad taste, foul smell and turbidity to water to which they are dumped.

Question 8.
What is the key difference between primary and secondary sewage treatment?
Answer:
Primary treatment is physical and removes grit and large prices of organic matter while secondary treatment is Biological causing digestion of organic matter by microbes.

Question 9.
Do you think microbes can also be used as source of energy? If yes, how?
Answer:
No, But their fermentation products Biogas, Alcohol, etc, are used as source of energy.

Question 10.
Microbes can be used to decrease the use of chemical fertilisers 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 (bio pesticide) 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, 8mg/L and 400mg/ 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:
B least BOD, so its river water A discharged from sewage treatment plant C highest BOD, untreated sewage water.

Question 12.
Find out the name of the microbes from which Cyclosporin A (an immuno-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 the following and discuss it with your teacher.
(a) Single cell protein (SCP)
(b) Soil
Answer:
(i) Single Cell protein – Used as food and feed with all essential Amino Acids, low fat. E.g.: Spirullina, yeast, Mushroom.
(ii) Soil –

• Humification
• Mineralisation – release minerals during degradation
• Biofertilizers
• Denitrification – Discuss about all with teacher.

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 acid, 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 biofertilisers enrich the fertility of the soil?
Answer:
Biofertilisers are micro-organisms which increases soil fertility and enhances nutrients to crop plants.

• Nitrogen fixing bacteria and Cyano bacteria
  Converts free N₂ from atmosphere to salts of N₂.
• Phosphate bacteria – Secrete phosphatase that dissolves insoluble phosphate from soil for absorption by plants.
• Mycorrhiza – occurs in forest plants solubilizes and absorbs nutrients from organic matter.

2nd PUC Biology Microbes in Human Welfare Additional Questions And Answers

2nd PUC Biology Microbes in Human Welfare One Mark Questions

Question 1.
What is LAB?
Answer:
The microorganisms which commonly grow in milk and converted into curd are called Lactic Acid Bacteria or LAB.

Question 2.
What changes are brought about in milk by LAB?
Answer:
LAB produces acids that coagulate and partially digest the milk proteins.

Question 3.
Who discovered pencillin?
Answer:
Alexander Fleming.

Question 4.
What are prions?
Answer:
Prions are proteinaceous infectious agents

Question 5.
What are fermentors?
Answer:
Fermentors are very large vessel used for growing microbes for the production of microbial products on an industrial scale.

Question 6.
What are antibiotics?
Answer:
The chemical substances which are produced by certain microbes which can kill or retard the growth of other microbes.

Question 7.
What is BOD?
Answer:
The amount of oxygen that would be consumed for the oxidation or decomposition of the biodegradable organic waste present in the water is called BOD or biological oxygen demand.

Question 8.
Name the organism used for the preparation of Swiss cheese?
Answer:
Propioni bacterium sharmani.

Question 9.
Name the enzyme used “clot buster” is to remove blood clots from blood vessels and which organism produces this enzyme.
Answer:
Streptokinase is know as clot buster. It is produced by Streptococcus bacteria.

Question 10.
What is the scientific name of brewer’s or baker’s yeast. (AI2009)
Answer:
Saccharomyces cerevisiae.

Question 11.
What is STP stands for?
Answer:
Sewage Treatment plant.

Question 12.
Name the free-living nitrogen-fixing bacteria in the soil.
Answer:
Azospirillum and Azotobacter.

Question 13.
Which of the following is a Cyanobacteria that can fix atmospheric nitrogen? Spirulina, Azospirillum, Sonalika.
Answer:
Azospirillum.

Question 14.
Milk starts to coagulate when Lactic Acid Bacteria is added to warm milk as a starter. Mention any other two benefits LAB provides. (AI CBSE – 2009)
Answer:
Increase vitamin B₁₂ and also check disease-causing microbes in stomach.

Question 15.
Name the group of organisms and the substrate they act on to produce biogas.
(CBSE 2009)
Answer:
Methanogens, Cellulose present in cattle excreta (cow dung)

Question 16.
What are floes?
Answer:
The masses of bacteria associated with fungal filaments forming the mesh like structures are the floes.

Question 17.
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 18.
Name the fungus that is being developed as a biocontrol.
Answer:
Trichoderma.

Question 19.
What is the key differences between primary and secondary sewage treatment?
Answer:
Primary treatment of sewage is a physical process, while the secondary treatment is a biological process.

Question 20.
Name a genus of a fungus that forms mycorrhiza.
Answer:
Glomus is the fungus that forms mycorrhiza.

Question 21.
List 2 advantages that a mycorrhizal association provides to the plant. (AI2008)
Answer:

• The fungal partner in mycorrhiza absorbs
• Phosphorus from soil and passes it on to the plant.
• The plants having mycorrhizal association show resistance to root borne pathogens and tolerance to salinity

2nd PUC Biology Microbes in Human Welfare Two Marks Questions

Question 1
(a) Name an eco-friendly hloherhicide which interferes with amino add synthesis and resistance to which has been obtained through transgenic culture.
(b) Name the first biopesticide. (CBSE 2004)
Answer:
Basta or phosphinothricin (ppt)
(a) It obtained from a product of Streptomyces species. Crop plants have been made resistant to it by transferring bar gene into them (e.g. wheat)
(b) Divine and college.

Question 2.
Match the columns

Answer:

Question 3.
Name the blank spaces ‘a’, ‘b’,’c’ and ‘d’ give in the following label.

Type of microbe	Scientific Name	Commercial or Product
Bacterium	a	Lactic acid
Fungus	b	Cyclosporin A stains
C	Monascus Purpur
Fungus	Penicillin Nolaltisin	d

Answer:

• a – Laetobaellhts
• b – Triehodmna polysptmtm
• c – Yeast (fungus)
• d – Penicillin

Question 4.
Name the blank spaces a, b, c, and d given in the following label. (CBSE – 2008)

Type of microbe	Scientific Name	Commercial or Product
Bacterium	a	Clot buster
b	Aspergillus Trichoderma	Enzyme citric acid
Fungus	Polysporum	c
Bacterium	d	Enzyme citric acid

Answer:
a – Streptococcus
b – Fungus
c – Cyclosporin A
d – Clostridium butylicum.

Question 5.
Fill in the blanks from Cephalosporin, Cyclosporin, Cycas, Soybean, Nepiatode, Fungus, Rhizobium. (CBSE 2008)
(a) Potent immunosuppressant drug is ………….. which is obtained from a …………..
(b) Roots pines and ………….. are associated will Amanita and …………..respectively.
Answer:
(a) Cyclosporin A, Fungus
(b) Soybean, Rhizobium.

Question 6.
(a) What is the source of statins and how they reduce the level of cholesterol in our body.
(b) Write the technical terms for VAM. Pickup examples of endomycorrhiza and ectomycorrhiza from sclerocystis, Laccaria, Gigaspora, glomas, Hebeloma, Psilocybes . (CBSE – 2006)
Answer:
(a) Stain which reduces the cholesterol level in our body is synthesized by the activity of yeast Monascus purpureus egs of statins are Lovastalin, simvastatin pravastatin, fluvastatin.

(b) VAM – It is vesicular arbuscular mycorrhiza where the hyphae send vesicular and branched haustoria into root cortical cells for obtaining nourishment in endomychorrhiza
eg:
Ectomychorrhiza – Laccaria, Hebeloma, Psilocybes
Endomuchorrhiza – Sclerocystis, Gigaspora, Glomos.

Question 7.
Name the blank spaces a, b, c and d from the table given below (CBSE 2007)

Type of Microbes	Scientific Name	Product	Medical Application
Fungus	a	Cyclosporin	b
c	Monascus	statin	d
	purpureus

Answer:
(a) Trichoderma polysporum
(b) Organs transplant patients
(c) Yeast (fungus)
(d) lowering blood cholesterol level.

Question 8.
Name the organism that causes large holes in “Swiss cheese”. How are these cause? (CBSE, Delhi 2009)
Answer:
Propioni bacterium sharmani. The large holes are due to the large quantity of carbon dioxide produced.

Question 9.
What are harmful effects of using chemical pesticides?
Answer:

• The chemical pesticides are harmful to many organisms (may be useful) other than the pests for which they used.
• They enter the food chain and cause diseases/disorders in various organism
• They are also highly toxic to man
• They cause pollution of our soil, water and air.

Question 10.
How do bacteria function as biofertilizers? Name 2 free-living soil bacteria that are biofertilizres.
Answer:

• Bacteria can fix atmospheric nitrogen into those nitrogen compounds which are used by the plants as their nutrients.
• Soil bacteria that are biofertilizers includes – Azotobacter and azospirillum.

2nd PUC Biology Microbes in Human Welfare Three Marks Questions

Question 1.
What are methanogens? Where are they generally found. Give examples.
Answer:
Methanogens are a group of anaerobic bacteria, which produce large quantities of methane from cellulosic materials.
E.g.: Methano bacterium Methanogens are found in

• The sewage wager
• Marshy place
• The rumen of cattle.

Question 2.
Describe the functions of anaerobic sludge in a sewage treatment plant.
Answer:

• A portion of the activated sludge from anaerobic sludge digester is pumped back to the aeration tank to serve as inoculum.
• The anaerobic bacteria digest the bacteria and fungi of the floes.
• The anaerobic bacteria in the sludge release CO₂, methane etc. during decomposition; these gases from the biogas is used as a source of energy, as it is inflammable.

Question 3.
What are mycorrhizae? How do they serve as biofertilizers or how are they useful to plants.
Answer:
Mycorrhizae are the symbiotic association between certain fungi and roots of higher plants.

• The fungus absorbs phosphorous from the soil and passes it to the plants
• Plants with mycorrhiza show resistance to root borne pathogens
• They show increased tolerance to salinity and drought
• There is an overall increase in plant growth and development.

Question 4.
Write about “Organic farming”.
Answer:
Organic farming is a holistic approach that seeks to develop an understandings of the webs of interaction among the myriads of organism that form the flora and fauna of the field.

• The organic matter works to create a system where the insects are not eradicated, but kept at managable levels by a complex system of checks and balance with in a leaving and vibrant ecosystem.
• According to former the eradication of the creatures, called pests, is not only possible but also undesirable because many beneficial predatory and parasitic insects cannot survive without them. Such method reduces the use the chemical pesticides and there by the pollution.

2nd PUC Biology Microbes in Human Welfare Five Marks 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.