Q. No.| 1. | Aerobic nitrate oxidation, and nitrite reduction |
| 2. | Decomposition of organic nitrogen, and conversion of dinitrogen to ammonium compounds |
| 3. | Enteric fermentation in cattle, and nitrogen fixation by Rhizobium in root nodules of legumes |
| 4. | Anaerobic ammonium oxidation, and denitrification |
Read the following four statements (I-IV):
| I. | Both, photophosphorylation and oxidative phosphorylation involve uphill transport of protons across the membrane |
| II. | In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth |
| III. | Stamens in flowers of Gloriosa and Petunia are polyandrous |
| IV. | Symbiotic nitrogen-fixers occur in a free-living state and also in soil |
How many of the above statements are right?
1. Three
2. Four
3. One
4. Two
1. convert free nitrogen to nitrogen compounds
2. convert proteins into ammonia
3. reduce nitrates to free nitrogen
4. oxidize ammonia to nitrates
The free-living, anaerobic nitrogen-fixer is:
1. Beijerinckia
2. Rhodospirillum
3. Rhizobium
4. Azotobacter
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 |
Which of the following is a symbiotic nitrogen fixer?
1. Glomus
2. Azotobacter
3. Frankia
4. Azolla
| 1. | Bradyrhizobium | 2. | Clostridium |
| 3. | Frankia | 4. | Azorhizobium |
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
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 |
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
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