Biological Nitrogen Fixation

Q. The biological conversion of ammonium to nitrite and then to nitrate is called .

1. nitrogen fixation
2. nitrification
3. ammonification
4. denitrification

Q. Plant can assimilate nitrogen in the form of

1. $N_2$
2. ${\mathrm{NO}}_2^{-}$
3. ${\mathrm{NO}}_3^{-}$
4. ${\mathrm{NH}}_3$

Q.

What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium. What is their role in N₂ -fixation?

Q. Which of the following organism causes nodule formation?

1. Azotobacter
2. Anabaena
3. Nostoc
4. Rhizobium

Q.

The enzyme nitrogenase is a

1. Fe-Protein

2. Mo-Protein

3. Mo-Fe Protein

4. Pure Protein

Q.

Match the column I and column II.
$\begin{array}{cc}ColumnI& ColumnII\\ A.Nitrobacter& 1.Free-livingaerobic{N}_{2}fixer\\ B.Clostridium& 2.Convertsammoniaintonitrite\\ C.Nitrosococcus& 3.Changesnitritetonitrate\\ D.Azotobacter& 4.Free-livinganaerobic{N}_{2}fixer\end{array}$

1. Codes
   $\begin{array}{ccccc}& A& B& C& D\\ & 2& 4& 3& 1\end{array}$

2. $\begin{array}{ccccc}& A& B& C& D\\ & 3& 4& 2& 1\end{array}$

3. $\begin{array}{ccccc}& A& B& C& D\\ & 4& 2& 1& 3\end{array}$

4. $\begin{array}{ccccc}& A& B& C& D\\ & 1& 2& 3& 4\end{array}$

Q. Write important feature of lichen

Q.

Assertion (A): Higher plants can not utilize nitrogen that is present in the form of $N_2$ in air.

Reason (R): In higher plants, the nitrogenase enzyme is absent.

1. Both A & R are true and R explains A

2. Both A & R are true and R does not explain A

3. A is true and R is False

4. Both A & R false