The free-living, anaerobic nitrogen - fixer is 

• Beijerinckia

• Rhodospirillum

• Rhizobium

• Rhizobium

Manganese is required in 

• nucleic acid synthesis

• plant cell wall formation

• photolysis of water during photosynthesis

• photolysis of water during photosynthesis

which one of the following is not a micronutrient?

• Molybdenum

• Magnesium

• Zinc

• Zinc

Nitrogen-fixation in root nodules of Alnus is brought about by

• Bradyrhizobium

• Clostridium

• Frankia

• Frankia

The two subunits of ribosome remain united at a critical ion level of

• Copper

• Manganese

• Manganese

• Manganese

Examination of blood of a person suspected of having anaemia, shows large, immature, nucleated erythrocytes without haemoglobin. Supplementing his diet with which of the following is likely to alleviate his symptoms?

• Thiamine

• Folic acid and cobalamine

• Riboflavin

• Riboflavin

Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statement is not correct during the process of nitrogen fixation?

• Leghaemoglobin scavenges oxygen and is pinkish in colour

• Nodules act as a site for nitrogen fixation

• The enzyme nitrogenase catalyse the conversion of atmospheric N₂ to NH₃

• The enzyme nitrogenase catalyse the conversion of atmospheric N₂ to NH₃

Which of the following is a symbiotic nitrogen fixer?

• Glomus

• Azotobacter

• Frankia

• Frankia

Which one of the following elements is not an essential micronutrient for plant growth?

• Mn

• Zn

• Cu

• Cu

Sulphur is an important nutrient for optimum growth and productivity in

• pulse crops

• cereals

• fibre crops

• fibre crops