For its action, nitrogenase requires :
1.  Light
2.  Mn²⁺
3.  Super oxygen radicals
4.  High input of energy

Read the following four statements (I-IV)
(I) Both, photophosphorylation and oxidative phosphorylation involve uphill transport of protons across the
membrane
(II) In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth
(III) Stamens in flowers of Gloriosa and Petunia are polyandrous
(IV) Symbiotic nitrogen-fixers occur in free-living state also in soil
How many of the above statements are right

1.  Three 

2. Four 

3. One 

4. Two 

Study the cycle shown below and select the option which gives correct words for all the four blanks A, B, C and D

  Options :
              A                          B                         C                                D
1. Denitrification      Ammonification              Plants                       Animals
2. Nitrification            Denitrification              Animals                     Plants
3. Denitrification           Nitrification                Plants                      Animals
4. Nitrification             Ammonification            Animals                     Plants

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

1. Nodules act as sites for nitrogen fixation

2. The enzyme nitrogenase catalyses the conversion of atmospheric N₂ to NH₃

3. Nitrogenase is insensitive to oxygen

4. Leghaemoglobin scavenges oxygen and is pinkish in colour

Which one of the following is essential for
photolysis of water ?
1. Boron
2. Manganese
3. Zinc
4. Copper

Which one of the following is not an essential
mineral element for plants while the remaining
three are ?
1. Phosphorus
2. Iron
3. Manganese
4. Cadmium

Sulphur is an important nutrient for optimum growth and productivity in :

1. pulse crops

2. cereals

3. fibre crops

4. oilseed crops

Farmers in a particular region were concerned that pre-mature yellowing of leaves of a pulse crop might cause 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 paints with cytokinins alongwith a small dose of nitrogenous fertilizer

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

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

A plant requires magnesium for :

1. holding cells together

2. protein synthesis

3. chlorophyll synthesis

4. cell wall development

Which one of the following elements is not an essential micronutrient for plant growth?
1. Mn
2. Zn
3. Cu
4. Ca