Questions - Answers
Very Short Answer Type Questions
1. Why does ‘Swiss Cheese’ have big holes? Name the bacteria responsible for it.
A: Swiss cheese has big holes due to large amount of CO2 produced by the bacteria Propionibacterium sharmanii.
2. What are fermenters?
A: Very large vessels used for production of beverages on an industrial scale are called fermenters.
3. Name a microbe used for statin production. How do statins lower blood cholesterol level?
A: Yeast – Monascus purpureus
Statins act as competitive inhibitors towards the enzymes responsible for synthesis of cholesterol. Thus they lower blood cholesterol level.
4. Why do we prefer to call secondary waste water treatment as biological treatment?
A: As we use flocs made of bacteria and fungal filaments and other anaerobic bacteria during treatment of sewage it is also called biological treatment.
5. What is Nucleopolyhedrovirus being used for now a days?
A: Nucleopolyhedrovirus are used as biological control agents which attack insects and other arthropods thus helping in pest control.
6. How has the discovery of antibiotics helped mankind in the field of medicine?
A: With reference to mankind we may call antibiotics as "Pro-life" that is they help life forms by acting against many disease causing microorganisms. Antibiotics improved our capacity to treat deadly diseases like plague, whooping cough, diphtheria, leprosy etc.
7. Why is distillation required for producing certain alcoholic drinks?
A: Drinks like Whisky, Brandy and Rum have high percentage of alcohol hence they should be heated at low temperatures and collected in the form of vapors. Thus distillation is required for producing alcoholic drinks with high alcohol percentage.
8. Write the most important characteristic that Aspergillus niger, Clostridium butylicum and Lactobacillus share.
A: All the three microorganisms are acid producers.
9. Give any two microbes that are useful in biotechnology.
A: * Saccharomyces cervisiae
* Acetobacter aceti
* Trichoderma polysporum
10. Name any two genetically modified crops.
A: * Bt Cotton
* Bt Brinjal
11. Why are blue green algae not popular as bio fertilizers?
A: Blue green algae /cyanobacteria are mostly aquatic and require high moisture content for their survival. They are free living and cannot readily form symbiosis with roots of crop plants like Rhizobium and Mycorrhizal fungi. Hence they are not popular as bio fertilizers.
12. Which species of Pencillium produces Roquefort cheese?
A: Pencillium roqueforti.
13. Name any two industrially important enzymes.
A: * Streptokinase
* Protease
* Pectinase
* Lipase
* (any two)
14. Name an immunosuppressive agent.
A: Cyclosporin A
15. Give an example of a rod shaped virus.
A: Tobacco Mosaic Virus (TMV)
16. What is the group of bacteria found in both the rumen of cattle and sludge of sewage treatment?
A: Methanogens.
17. Why are cyanobacteria considered useful in paddy fields? Cyanobacteria like Anabaena, Nostoc, Oscillatoria fix atmospheric nitrogen into the soil.
A: They also add organic matter to the soil and increase fertility of the soil. Hence they are considered to be useful in paddy fields.
18. In which food would you find lactic acid bacteria? Name the bacterium. Milk and milk products.
A: Lactobacillus
19. Name any two fungi which are used in the production of antibiotics.
A: Pencillium notatum and
20. Name the scientists who were credited for showing the role of penicillin as an antibiotic.
A: Ernest Chain and Howard Florey.
Short Answer Type Questions
1. What are bio fertilizers? Give two examples and discuss their role as bio fertilizers.
A: Bio fertilizers are organisms that enrich the nutrient quality of the soil.
Examples of bio fertilizers:
* Bacteria – Rhizobium, Azospirillum, Azotobacter
* Fungi – Glomus
* Cyano bacteria – Anabaena, Nostoc, Oscillatoria
Role of organisms as bio fertilizers:
* Rhizobium fixes atmospheric nitrogen into ammonia by symbiotic association with legume roots which is absorbed by the plant.
* Azospirillum and Azotobacter are free living nitrogen fixing bacteria.
* Glomus forms mycorrhizae in symbiosis with root of higher plants and helps in absorption of phosphorus from the soil.
* It also protects the plants from root borne pathogens, offers tolerance to salinity and drought, helps in increase of plant growth.
* Cyano bacteria not only fix nitrogen but also add organic matter to the soil.
2. How do Mycorrhizal fungi help the plants harbouring them?
A: Mycorrhizae are symbiotic associations of fungal hyphae on roots of higher plants.
* Genera like Glomus form mycorrhiza on the roots.
* This association helps in absorption of phosphorus by the plant.
* The mycorrhiza also confers resistance to root-borne pathogens.
* It provides tolerance to salinity and drought.
* It assists in overall increase in plant growth and development.
Long Answer Type Question
1. Write a brief essay on microbes used as bio control agents.
A: Bacteria, fungi and viruses are used as bio control agents in agriculture. Bacteria like Bacillus thuringiensis are used to control butterfly caterpillars which feed on leaves of crop plants. The bacteria are available as dried spores which are mixed with water and sprayed on the affected crop. The bacteria destroy only caterpillars by producing toxins in the gut of the larva. But these bacteria do not harm other useful insects. Hence Bacillus thuringiensis genes are used in genetic engineering to produce genetically modified crops like Bt cotton and Bt brinjal. Trichoderma viridi is a free living fungus which inhabits the rhizosphere. It has antagonistic properties against disease causing bacteria and fungi. Thus it protects the roots from infection of pathogens. Hence it is used as a bio control agent. Baculo viruses like NPV (Nuclear Polyhedrosis Virus) and CPV (Cytoplasmic Polyhedrosis Virus) act against arthropods insects and hence used to control them. They are species specific and have no negative impact on plants, mammals, birds etc. Hence NPVs are variously used in integrated pest management programmes.
