Leghaemoglobin is produced in response to

1. respiration 

2. photosynthesis

3. fatty acid synthesis

4. N₂ fixation.
 

Which enzyme complex is responsible for the reduction of molecular nitrogen to the level of NH₃ in

root module of legume?

(1) Aminase

(2) Nitrogenase

(3) Nitrate reductase

(4) Nitrite reductase

The function of leghaemoglobin during biological nitrogen fixation in root nodules of legumes is to
1. convert atmospheric N₂ to NH₃
2. convert ammonia to nitrite
3. transport oxygen for activity of nitrogenase
4. protect nitrogenase from oxygen.

The function of leghaemoglobin is

1. to provide oxygen to leg muscles of nitrogen-fixing

2. to protect oxygen-sensitive enzymes of nitrogen fixing bacteria in the root nodules of

legumes

3. to walk to the sites where oxygen is required

4. to function when haemoglobin is not available.

Farmers in a particular region were concerned that pre-mature yellowing of leaves of a pulse crop might cause a decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield?

1. Frequent irrigation of the crop

2. Treatment of the plants with cytokinins along with a small dose of nitrogenous fertilizer

3. Removal of all yellow leaves and spraying the remaining green leaves with 2, 4, 5 trichloro phenoxy acetic acid

4. Application of iron and magnesium to promote the synthesis of chlorophyll

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

1. Mn

2. Zn

3. Cu

4. Ca

Which of the following is a symbiotic nitrogen fixer?

1. Glomus

2. Azotobacter

3. Frankia

4. Azolla

The free-living, anaerobic nitrogen-fixer is

1. Beijerinckia

2. Rhodospirillum

3. Rhizobium

4. Azotobacter

An organism used as a biofertilizer for raising soyabean crop is

1. Azospirillum

2. Rhizobium

3. Nostoc

4. Azotobacter

Nitrifying bacteria

1. convert free nitrogen to nitrogen compounds

2. convert proteins into ammonia

3. reduce nitrates to free nitrogen

4. oxidize ammonia to nitrates