| The enzyme responsible for the reduction of molecular nitrogen to the level of ammonia in the leguminous root nodules is |
| a) | Amminase | b) | Nitrogenase |
| c) | Nitrate reductase | d) | Nitrite reductase |
| (b)Rhizobium leguminosarum causes biological nitrogen fixation in root nodules of leguminous plants. A pigment leghaemoglobin is present in the root nodules, which is a oxygen scavenger, i.e., protect the enzyme nitrogenase from oxygen. Nitrogen enzyme complex consists of two components, i.e., the Fe-protein and Mo-Fe protein. |