Mineral Nutrition · Question 21

Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N2) to the atmosphere?

1. Aerobic nitrate oxidation and nitrate 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

For its action, nitrogenase requires

1. high input of energy
2. light
3. Mn2+
4. super oxygen radicals

Which one of the following is wrong statement?

1. Anabaena and Nostoc are capable of fixing nitrogen in 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 chemo-autotrophs.

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 correctly matched?

1. Passive transport of nutrients – ATP
2. Apoplast – Plasmodesmata
3. Potassium – Readily immobilisation
4. Bakane of rice seedlings – F. Skoog

Which one of the following is essential for photolysis of water?

1. Copper
2. Manganese
3. Boron
4. Zinc

Which one of the following is not an essential mineral element for plants while the remaining three are?

1. Iron
2. Manganese
3. Cadmium
4. Phosphorus

Which one of the following elements in plants is not remobilised?

1. Phosphorus
2. Calcium
3. Potassium
4. Sulphur

Nitrifying bacteria

1. oxidize ammonia to nitrates
2. convert free nitrogen to nitrogen compounds
3. convert proteins into ammonia
4. reduce nitrates to free nitrogen

The function of leghaemoglobin in the root nodules of legumes is

1. inhibition of nitrogenase activity
2. oxygen removal
3. nodule differentiation
4. expression of nif gene