An element playing important role in nitrogen fixation is  fro

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 Multiple Choice QuestionsMultiple Choice Questions

1.

In which of the following, all three are macronutrients

  • Iron, copper, molybdenum

  • Molybdenum, magnesium, manganese

  • Nitrogen, nickel, phosphorous

  • Nitrogen, nickel, phosphorous

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2.

The first stable product of fixation of atmospheric nitrogen in leguminous plants is

  • NO2-

  • ammonia

  • NO3-

  • NO3-

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3.

During biological nitrogen fixation inactivation of nitrogenase by oxygen poisoning is prevented by

  • Leghaemogolobin

  • Xanthophyll

  • Carotene

  • Carotene

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4.

Best defined function of manganese in green plants is

  • Photolysis of water

  • Calvin cycle

  • Nitrogen fixation

  • Nitrogen fixation

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5.

Consumption of which one of the following foods can prevent the kind of blindness associated with vitamin ‘A’ deficiency?

  • ‘Flaver Savr’ tomato

  • Canolla

  • Golden rice

  • Golden rice

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6.

For its action, nitrogenase requires

  • high input of energy

  • light

  • Mn2+

  • Mn2+

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7.

Minerals known to be required in large amounts for plant growth include

  • phosphorus, potassium, sulphur, calcium

  • calcium, magnesium, manganese, copper

  • potassium, phosphorus, selenium, boron

  • potassium, phosphorus, selenium, boron

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8.

Which one of the following elements in plants is not remboilised?

  • Calcium

  • Potassium

  • Sulphur

  • Sulphur

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9.

Which one of the following is not an essential mineral elements for plants while the remaining three are?

  • Iron

  • Manganes

  • Cadmium

  • Cadmium

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10.

An element playing important role in nitrogen fixation is 

  • Molybdenum

  • copper

  • manganese

  • manganese


A.

Molybdenum

Molybdenum is absorbed as molybdate by plants. It is involved in nitrogen metabolism including nitrogen fixation. It is a component of enzyme nitrogenase and acts as an enzyme activator. Its deficiency cause chlorosis and necrosis, whiptail of cauliflower and premature leaf fall. 

Copper is absorbed by the plant in ionic form. Its deficiency causes necrosis, die back in Citrus, reclamation in legumes.

Manganese is absorbed by the plants as a bivalent ion. It acts as the enzyme activator. Its deficiency causes interveinal chlorosis as well as yellowing of starch and their subsequent degenerate. 

Zinc is needed for biosynthesis of IAA and also acts as the enzyme activator. Its deficiency causes chlorosis, little leaf, rosette, the white bud of maize and mottling of leaves.

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