For its action, nitrogenase requires:
1. Light
2. Mn2+
3. Super oxygen radicals
4. High input of energy
Study the cycle shown below and select the option which gives the correct words for all four blanks A, B, C, and D:
Options:
A | B | C | D | |
1. | Denitrification | Ammonification | Plants | Animals |
2. | Nitrification | Denitrification | Animals | Plants |
3. | Denitrification | Nitrification | Plants | Animals |
4. | Nitrification | Ammonification | Animals | Plants |
Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statements is not correct during this process of nitrogen fixation:
1. | Nodules act as sites for nitrogen fixation |
2. | The enzyme nitrogenase catalyses the conversion of atmospheric N2 to NH3 |
3. | Nitrogenase is insensitive to oxygen |
4. | Leghaemoglobin scavenges oxygen and is pinkish in colour |
Which one of the following is essential for the photolysis of water?
1. Boron
2. Manganese
3. Zinc
4. Copper
Which one of the following is not an essential mineral element for plants while the remaining three are?
1. Phosphorus
2. Iron
3. Manganese
4. Cadmium
The deficiencies of micronutrients, not only affect the growth of plants but also vital functions such as photosynthetic and mitochondrial electron flow. Among the list given below, which group of three elements shall affect most, both photosynthetic and mitochondrial electron transport:
1. Ca, K, Na
2. Co, Ni, Mo
3. Mn, Co, Ca
4. Cu, Mn, Fe
All of the following statements concerning the Actinomycetous filamentous soil bacterium Frankia are correct EXCEPT that Frankia:
1. | Forms specialized vesicles in which the nitrogenase is protected from oxygen by a chemical barrier involving triterpene hopanoids |
2. | Can induce root nodules on many plant species |
3. | Like Rhizobium, it usually infects its host plant through root hair deformation and stimulates cell proliferation in the host's cortex |
4. | Cannot fix nitrogen in the free-living state |
Which of the following is a non–symbiotic nitrogen fixing bacteria?
1. Rhizobium
2. Mycorrhiza
3. Azotobacter
4. Nitrosomonas
If by radiation all nitrogenase enzymes are inactivated, then there will be no:
1. Fixation of atmospheric nitrogen
2. Conversion from nitrate to nitrite in legumes
3. Conversion from ammonium to nitrate in soil
4. Fixation of nitrogen in legumes
Nitrogen-fixing bacteria converts:
1.
2.
3.
4.