Biology Multiple Choice Questions on “Microbes as Biofertilizers”.
1. With our present-day lifestyles, what is a major cause of concern?
a) Inflation
b) Poverty
c) Illiteracy
d) Environmental Pollution
Answer: d
Clarification: With our present-day lifestyles, environmental pollution is a major cause of concern. The use of chemical fertilisers to meet the ever-increasing demand for agricultural produce has contributed significantly to this pollution.
2. Why is there a need to switch to organic farming?
a) Increasing poverty
b) Increasing road accidents
c) Increasing environmental pollution
d) Increasing population
Answer: c
Clarification: There are a lot of problems associated with the overuse of chemical fertilisers like environmental pollution, soil pollution, thermal pollution, etc. Therefore, there is a large pressure to switch to organic farming which includes the use of bioresources like bio-fertilisers which can be recycled.
3. Which of the following is not a type of manure?
a) Farmyard manure
b) Compost manure
c) Platinum manure
d) Green manure
Answer: c
Clarification: Manure is a semi-decayed organic matter which is added to the soil to maintain its fertility, crumb structure, aeration and hydration capacities. There are three types of manure commonly found in the farms-farmyard manure, compost manure and green manure.
4. Which of the following is not used as a bio-fertiliser?
a) Bacteria
b) Algae
c) Cyanobacteria
d) Fungi
Answer: b
Clarification: Bio fertilisers are organisms that enrich the nutrient quality of the soil. The main sources of bio-fertilisers are bacteria, fungi and cyanobacteria.
5. Rhizobium is a free-living bacterium that fixes atmospheric nitrogen.
a) True
b) False
Answer: b
Clarification: The nodules on the root of some leguminous plants are in the symbiotic association with Rhizobium. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient.
6. Which of the following is not a free-living Nitrogen-fixing bacteria?
a) Azotobacter
b) Clostridium
c) Klebsiella
d) Xanthomonas
Answer: d
Clarification: Some of the free-living Nitrogen-fixing bacteria are-Azotobacter, Clostridium, Klebsiella and Beijerinckia. Rhizobium, Xanthomonas and Frankia are some of the symbiotic Nitrogen-fixing bacteria.
7. Which of the following is an aerobic nitrogen-fixing bacterium?
a) Azotobacter
b) Clostridium
c) Rhodospirillum
d) Rhodopseudomonas
Answer: a
Clarification: Some of the aerobic nitrogen-fixing bacteria are Azotobacter and Beijerinckia. Some of the anaerobic nitrogen-fixing bacteria are Clostridium, Rhodospirillum and Rhodopseudomonas. Soil is enriched through exudation and formation of nitrates after their death and decay.
8. Which of the following bacteria cannot fix atmospheric nitrogen?
a) Nostoc
b) Anabaena
c) Oscillatoria
d) Lactobacillus
Answer: d
Clarification: Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen like Nostoc, Anabaena and Oscillatoria.
9. Presence of which of the following elements is required for nitrogen fixation?
a) Phosphorus
b) Carbon
c) Silver
d) Oxygen
Answer: a
Clarification: Presence of Phosphorous is essential for nitrogen fixation. Plants having symbiotic bacteria have higher protein content. No external nitrogen fertilizer is required.
10. Which of the following statements is not related to mycorrhiza?
a) Many members of genus Glomus forms mycorrhiza
b) Fungal symbiont absorbs nitrogen
c) Plants show resistance to root-borne pathogens
d) There is an overall increase in plant growth and development