Which of the following bacteria reduce nitrate in soil into nitrogen?
1. Nitrobacter
2. Thiobacillus
3. Nitrococcus
4. Nitrosomonas
The common nitrogen-fixer in paddy fields is
(1) Frankia
(2) Rhizobium
(3) Azospirillum
(4) Oscillatoria
A free living aerobic soil bacterium capable of
fixing nitrogen is
1. Azotobacter
2. Clostridium
3. Rhizobium
4. Streptococcus
During biological nitrogen fixation, the cells of which of the following regions take part in the formation of nodules in roots for bacteroides?
1. Epidermis
2. Cortex
3. Endodermis
4. Vascular bundle
Thiobacillus is a group of bacteria helpful in carrying out:
1. Denitrification
2. Nitrogen fixation
3. Chemoautotrophic fixation
4. Nitrification
A plant requires magnesium (Mg) for:
1. holding cells together
2. protein synthesis
3. chlorophyll synthesis
4. cell wall development
Which of the following is responsible for biological nitrogen fixation?
1. Nif gene
2. Nitrogenase
3. Both 1. and 2.
4. RNA synthetase
Which of the following is a non-symbiotic nitrogen fixer organism?
1. VAM
2. Azotobacter
3. Anabaena
4. Rhizobium
Azotobacter and Bacillus polymyxa are
1. Decomposers
2. Nonsymbiotic nitrogen fixer
3. Symbiotic nitrogen fixer
4. Pathogenic bacteria
Which of the following is a flowering plant with nodules containing filamentous nitrogen-fixing microorganism?
1. Casuarina equisetifolia
2. Crotolaria juncea
3. Cycas revoluta
4. Cicer arietinum