Mineral Nutrition — Page 8 | NEET Biology

Q71

Which of the following is a symbiotic nitroger fixer?

A Azotobacter

B Frankia

C Azolla

D Glomus

Correct Answer

Option B

Solution

(b) Frankia is a symbiotic nitrogen fixer in root nodules of several non-legume plants like Casurina and Alnus.

Q72

One of the free -living, anaerobic nitrogen fixer is:

A Beijernickia

B Rhodospirillum

C Rhizobium

D Azotobacter

Correct Answer

Option B

Solution

(b) Rhodospirillum is a free-living, anaerobic nitrogen fixer bacteria.

It can synthesize its food in presence of light under anaerobic conditions.

Beijernickia and Azotobacter are free living aerobic nitrogen fixing bacteria.

Rhizobium is a symbiotic nitrogen fixing bacteria.

Q73

An element playing important role in nitrogen fixation is :

A Molybdenum

B Copper

C Manganese

D Zinc

Correct Answer

Option A

Solution

(a) Molybdenum is a micronutrient that plays an important role in nitrogen fixation.

It is a part of nitrate reductase enzyme that helps in nitrogen fixation.

Q74

The function of leg haemoglobin in the root nodules of legumes is :

A inhibition of nitrogenase activity

B oxygen removal

C nodule differentiation

D expression of nif gene

Correct Answer

Option B

Solution

(b) Leghaemoglobin is the haemoglobin like red pigment found in root nodules of legumes and reported to function as an oxygen-carrying pigment in symbiotic nitrogen fixation.

Q75

Nitrifying bacteria :

A oxidize ammonia to nitrates

B convert free nitrogen to nitrogen compounds

C convert proteins into ammonia

D reduce nitrates to free nitrogen

Correct Answer

Option A

Solution

(a) The nitrifying bacteria bring about transformations of ammonia to nitrite and of nitrite to nitrate.

Q76

A prokaryotic autotrophic nitrogen fixing symboint is found in :

A Alnus

B Cycas

C Cicer

D Pisum

Correct Answer

Option B

Solution

(b) A prokaryotic autotrophic nitrogen fixing symbiont is found in Cycas.

All known Cycads form mutualistic, facultative symbioses with nitrogen fixing cyanobacteria (formerly known as the blue-green algae).

Cycads provide fixed carbon and a stable environment to the cyanobacteria in exchange for fixed nitrogen.

These cyanobacteria are endosymbionts, living within the roots of Cycads.

Q77

For its action, nitrogenase requires

A

Mn^{2+}

B light

C high input of energy

D super oxygen radicals

Correct Answer

Option C

Solution

(c) Nitrogenases are the enzymes used by some organisms to fix atmospheric nitrogen gas.

It is the only known family of enzymes that accomplish this process.

Nitrogenase requires high input of energy & anaerobic condition.

Q78

Read the following four statements (A-D).

A Two

B Three

C Four

D One

Correct Answer

Option C

Solution

(c) All the four statements are correct.

Q79

Which one of the following is wrong statement?

A Anabaena and Nostoc are capable of fixing nitrogen in free living state also

B Root nodule forming nitrogen fixers live as aerobes under free-living conditions.

C Phosphorus is a constituent of cell membranes, certain nucleic acids and cell proteins.

D Nitrosomonas and Nitrobacter are chemoautotrophs.

Correct Answer

Option C

Solution

(c) Phosphorus is a constituent of nucleic acids of both DNA and RNA but absent in cell membranes and cell proteins.

Q80

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

A calcium, magnesium, manganese, copper

B potassium, phosphorus, selenium, boron

C magnesium, sulphur, iron, zinc

D phosphorus, potassium, sulphur, calcium

Correct Answer

Option D

Solution

(d) P, K, S, Ca are all macronutrients required in large amounts.