Q. No.During biological nitrogen fixation, inactivation of nitrogenase by oxygen poisoning is prevented by?
1. Leghaemoglobin
2. Xanthophylls
3. Carotene
4. Cytochrome
The oxygen evolved during photosynthesis comes from water molecules. Which one of the following pairs of elements are involved in this reaction?
1. Manganese and chlorine
2. Manganese and potassium
3. Magnesium and molybdenum
4. Magnesium and chlorine
Minerals known to be required in large amounts for plant growth include:
1. phosphorus, potassium, sulphur, calcium
2. calcium, magnesium, manganese, copper
3. potassium, phosphorus, selenium, boron
4. magnesium, sulphur, iron, zinc
Deficiency symptoms of nitrogen and potassium are visible first in:
1. Senescent leaves
2. Young leaves
3. Roots
4. Buds
2. Nitrite
3. Glutamate
4.
1. Magnesium
2. Calcium
3. Phosphorus
4. Sulphur
| 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 |
Best defined function of manganese in green plants is :
1. Photolysis of water
2. Calvin cycle
3. Nitrogen fixation
4. Water absorption
Which one of the following is a wrong statement?
| 1. | Anabaena and Nostoc are capable of fixing nitrogen in a free-living state also |
| 2. | Root nodule-forming nitrogen fixers live as aerobes under free-living conditions |
| 3. | Phosphorus is a constituent of cell membranes, certain nucleic acids, and all proteins |
| 4. | Nitrosomonas and Nitrobacter are chemoautotrophs |
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