During nitrogen fixation, nitrite is oxidized to nitrate with the help of the bacterium:

1. Nitrosomanas
2. Pseudomonas
3. Nitrobacter
4. Thiobacillus

 

Nitrogen-fixing nodules on the roots of non-leguminous plants like Alnus are produced by
1. Rhizobium
2. Beijernickia
3. Azotobacter
4. Frankia

For each molecule of ammonia produced by nitrogenase, the number of ATP molecules required are:
1. 4
2. 8
3. 12
4. 16

The deficiency symptoms of iron, magnesium and calcium in plants may actually be due to the toxicity of
1. Potassium
2. Manganese
3. Iron
4. Chlorine

The criteria for essentiality of an element for a plant include all except:
1. It must be absolutely necessary for supporting normal growth and reproduction
2. The requirement must be specific and not replaceable by another element
3. It must be directly involved in the metabolism of the plant.
4. They must be present in the plants in a concentration in excess of 10 mmole/Kg of dry matter.

Identify the incorrectly matched pair

    Mineral                     Functions in plants

1. Potassium                 Opening and closing of stomata, Activation of enzymes

2. Magnesium                Maintenance of ribosome structure, Structure of chlorophyll

3. Boron                        Pollen germination, Carbohydrate translocation

4. Molybdenum               Water splitting in photosynthesis, Nitrogen metabolism

How many ATP molecules are required to biologically fix one molecule of nitrogen into two molecules of ammonia?
1. 4
2. 8
3. 12
4. 16

When the plants are grown in magnesium deficient but urea rich soil, the symptoms expressed are:
1. yellowish leaves
2. colourless petiole
3. dark green leaves
4. shoot apex die.

Select the mismatch.

(1) Frankia                      Alnus

(2) Rhodospirillium            Mycorrhiza

(3) Anabaena                   Nitrogen fixer

(4) Rhizobium                 Alfa-fa

Which is essential for the growth of root tip?
(1) Zn

(2) Fe

(3) Ca

(4) Mn