Nodule Formation

Q.

The correct sequence of events in nodule formation is:

1. Curling of root hairs - rapid division of cortical cells - production of infection thread - bacteria enters polyploidy cells - colonization of surrounding areas of roots

2. Rapid division of cortical cells - production of infection thread - curling of root hairs - colonization of surrounding areas of roots - bacteria enters polyploidy cells

3. Colonization of surrounding areas of roots - curling of root hairs - production of infection thread - rapid division of cortical cells - bacteria enters polyploidy cells

4. Colonization of surrounding areas of roots - rapid division of cortical cells - bacteria enters polyploidy cells - curling of root hairs - production of infection thread

Q. If the nitrogenase enzyme has been inactivated by radiation, there will be no

1. fixation of atmospheric nitrogen
2. conversion of nitrite to nitrate
3. fixation of nitrogen by microorganisms
4. conversion of ammonia into nitrite

Q. From the options given below, identify the gene responsible for nitrogen fixation.

1. Nif
2. Nitrogenase
3. Leg-haemoglobin
4. None of the above

Q. Which of the following is incorrect about nitrogen fixation in root nodule?

1. It requires nitrogenase enzyme.

2. Leghaemoglobin acts as oxygen scavenger.

3. Mg is required as cofactor for nitrogenase enzyme.
4. Process uses atmospheric nitrogen.