6
MCQ (Single Correct Answer)
With regard to the biological nitrogen fixation by Rhizobium in association with soyabean, which one of the following statement/ statements does not hold true.
A
Nitrogenase may require oxygen for its functioning.
B
Nitrogenase is Mo-Fe protein
C
Leg-haemoglobin is a pink coloured pigment.
D
Nitrogenase helps to convert $\mathrm{N}_2$ gas into two molecules of ammonia.
7
MCQ (Single Correct Answer)
Match the element with its associated functions/roles and choose the correct option among given below
| A. | Boron | 1. | Splitting of $\mathrm{H}_2 \mathrm{O}$ to liberate $\mathrm{O}_2$ during photosynthesis |
|---|---|---|---|
| B. | Manganese | 2. | Needed for synthesis of auxins |
| C. | Molybdenum | 3. | Component of nitrogenase |
| D. | Zinc | 4. | Pollen germination |
| E. | Iron | 5. | Component of ferredoxin |
A
$1,2,3,4,5$
B
$4,1,3,2,5$
C
$3,2,4,5,1$
D
$2,3,5,1,4$
8
MCQ (Single Correct Answer)
Plants can be grown in (Tick the incorrect option)
A
soil with essential nutrients.
B
water with essential nutrients.
C
either water or soil with essential nutrients.
D
water or soil without essential nutrients.
9
Name a plant, which accumulate silicon.
Explanation
Oryza sativa and Triticum aestivum are silicon accumulators. These plants actively absorb silicon and accumulate them in their biomass.
10
Mycorrhiza is a mutualistic association. How do the organisms involved in this association gain from each other?
Explanation
A mycorrhiza is a symbiotic association between a fungus and the roots of vascular plants (mainly gymnosperms). This mutualistic association provides fungus a constant and direct supply of carbohydrates (glucose and sucrose).
In return, plant gains the benefit of the mycelium of fungus which enhances its absorptive capacity for water and minerals due to the large surface area of mycelium.