Mineral Nutrition

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?

• Leghaemoglobin scavenges oxygen and it is pinkish in colour.

• Nodules act as sites for nitrogen fixation.

• The enzyme nitrogenase catalyses the conversion of atmospheric N2 to NH3 .

• Nitrogenase is insensitive to oxygen.

Study the cycle shown below and select the option which gives the correct word for all the four blanks A, B, C and D

• A: Nitrification, B: Ammonification, C: Animals, D: Plants

• A: Denitrification, B: Ammonification, C: Plants, D: Animals

• A: Nitrification, B: Denitrification, C: Animals, D: Plants

• A: Denitrification, B: Nitrification, C: Plants, D: Animals

An element playing important role in nitrogen fixation is

• Molybdenum

• Copper

• Manganese

• Zinc

Which one of the following is not a micronutrient?

• Molybdenum

• Magnesium

• Zinc

• Boron

The free-living, anaerobic nitrogen-fixer is

• Beijerinckia

• Rhodospirillum

• Rhizobium

• Azotobacter

The common nitrogen-fixer in paddy fields is

• Rhizobium

• Azospirillum

• Oscillatoria

• Frankia

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

• Iron

• Manganese

• Cadmium

• Phosphorus

The function of leghaemoglobin in the root nodules of legumes is

• Oxygen removal

• Nodule differentiation

• Expression of nif gene

• Inhibition of nitrogenase activity

Nitrifying bacteria

• Convert free nitrogen to nitrogen compounds

• Convert proteins into ammonia

• Reduce nitrates to free nitrogen

• Oxidize ammonia to nitrates

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

• Calcium

• Potassium

• Sulphur

• Phosphorus