Question No:1

Nitrate present in the soil is also reduced to nitrogen by the process of denitrification it is carried out by

[A] pseudomonas
[B] thiobacillus
[C] rhizobium
[D] both (a) and (b)



Question No:2

Reduction of nitrogen to ammonia by living organism is called

[A] nitrification
[B] denitrification
[C] biological nitrogen fixation
[D] ammonification



Question No:3

N=N->NH₃
Reaction catalyzed by enzyme:

[A] Isomerase
[B] Nitrogenase
[C] Carbonic anhydrase
[D] Higase



Question No:4

Frankia produced nitrogen by fixing nodule on

[A] lentils
[B] garden pea
[C] alnus
[D] broad bean



Question No:5

Which of the following statement is incorrect?

[A] Rhizobium and frankia are free living bacteria of soil
[B] Rhizobium is rod shaped (Bacillus)
[C] Root nodule of pulse are pink due to the presence of leg-hemoglobin
[D] Rhizobium and frankia can fix nitrogen as free living bacteria



Question No:6

Leg-hemoglobin means

[A] low grade hemoglobin
[B] luminous hemoglobin
[C] leguminous hemoglobin
[D] low level hemoglobin



Question No:7

Sequential stage for principal stages of nodule formation are
(1) Rhizobia multiply and colonies the surrounding roots.
(2) Rhizobia attached to epidermal and root hair cells.
(3) Root hair curl and bacterial invade root hair.
(4) Initiation of nodule formation in cortex.
(5) Infection thread is produced carrying bacteria to cortex.
(6)Bacteria released from thread into cells and causes their differentiation in specialized nitrogen fixing cells
(7) Nodule formed establish, a direct vascular connection with the host for exchange of nutrient,

[A] I->VII->II->Vl ->III->V->IV
[B] II->III-> IV->I-> VII-> V-> VI
[C] VII->VI–> IV-> I –>III -> V-> II
[D] I-> II-> III-> V-> IV-> VI->Vll



Question No:8

Root nodule of leguminous plant contains

[A] Nitrogenase
[B] leg hemoglobin
[C] both
[D] none



Question No:9

Enzyme nitrogenase is

[A] Mo-Fe protein
[B] Mo-Mn protein
[C] Mn-Fe protein
[D] Cu-Fe protein



Question No:10

Which cells are divided for nodule formation?

[A] Inner cortex
[B] Pericycle
[C] Endodermis
[D] Both (a) and (b)



Question No:11

For production of 2 mol. NH₃ how much ATP is required in biological nitrogen fixation reaction (i. e. N₂ ->2NH₃)?

[A] 4
[B] 8
[C] 16
[D] 32



Question No:12

Nitrogenase require _______ condition for its activity,

[A] aerobic
[B] anaerobic
[C] ozonised environment
[D] CO₂



Question No:13

Which of the following is incorrect about nitrogen fixation in nodule?

[A] It is a high energy process
[B] Leg-hemoglobin acts as oxygen scavenger
[C] Mg is required as a cofactor for nitrogenase enzyme
[D] Process use atmospheric nitrogen but not atmospheric hydrogen directly



Question No:14

Fats of NH₃ formed during biological nitrogen fixation is

[A] NH₃ protonated to form
[B] NH₄⁺ ion formed used for reductive amination
[C] glutamic acid formed under reductive amination undergo transamination
[D] all



Question No:15

Which is the main amino acid that is used for transamination?

[A] Tyrosine
[B] Proline
[C] Glutamic acid
[D] Alanine