Which one of the following elements is not an essential micronutrient for plant growth? 
Essential micro elements are Fe, Mn, Zn, B, Cu, Mo and essential macronutrionts are C,H, N, P, S, Ca, K, Mg.
Nitrogen fixation in root nodules of Alnus is brought about by: 
Nitrogen fixation in root nodules of Alnus is brought about by Frankia. Frankia is a symbiotic nitrogen fixing bacteria in root nodules of several nonlegune plants like Casuarina (Australian Pine), Myrica and Alnus (Alder).
Manganese is required in: 
Manganese is essential for many plant functions. Some of them are:
Which one of the following pairs is wrongly matched? 
Alcohol and nitrogenase pair is wrongly matched. Ethanol produces alcohol.
Which of the following is a symbiotic nitroger fixer?
Frankia is symbiotic nitrogen fixer in root nodules of several non-legume plants like Casurina and Alnus.
An element playing important role in nitrogen fixation is : 
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.
Which one of the following is not a micronutrient? 
Magnesium is a macronutrient. Micronutrients are essential elements that are required by plants in small amount. They include Fe, Cu, B, Mo, Mn, Cl, and Ni. Macronutrients, on the other hand, are those essential elements that are required by plants in larger amount. The examples include C, H, O, N, S, P, K, Ca and Mg.
One of the free -living, anaerobic nitrogen - fixer is: 
Rhodospirillum is a free-living, anaerobic nitrogen fixer bacteria. It can synthesize its food in presence of light under anaerobic condition.
Beijernickia and Azotobacter are free living aerobic nitrogen fixing bacteria. Rhizobium is a symbiotic nitrogen fixing bacteria.
A prokaryotic autotrophic nitrogen fixing symboint is found in : 
A prokaryotic autotrophic nitrogen fixing symbiont is found in Cycas.
Which one of the following elements in plants is not remobilised? 
Calcium is not remobilized from the leaves to the fruits, like potassium, phosphorus and sulphur. It occurs abundantly in a non-exchangeable form such as anorthite (CaAl2Si2O8).
Nitrifying bacteria : 
The nitrifying bacteria bring about transformations of ammonia to nitrite and of nitrite to nitrate.
The function of leg haemoglobin in the root nodules of legumes is : 
Leghaemoglobin is the haemoglobin like red pigments found in root nodules of legumes and reported to function as an oxygen-carrying pigment in symbiotic nitrogen fixation.
Which one of the following is not an essential mineral element for plants while the remaining three are? [2011M]
Cadmium is not an essential element for
plants. Phosphorus is macronutrient and iron and manganese are micronutrients for plants.
Which one of the following is essential for photolysis of water ? [2011M]
Photolysis is catalysed by the proteinbound inorganic complex containing manganese ions (oxygen evolving complex) of photosystem II.
Best defined function of Manganese in green plants is : 
The best defined function of manganese is in the splitting of water to liberate oxygen during photosynthesis. It is absorbed in the form of manganous ions (Mn2+). It activates many enzymes involved in photosynthesis, respiration and nitrogen metabolism.
Which one of the following is correctly matched ? 
Correct option (c) Potassium - Readily immobilisation
Explanation : Active transport of nutrients require ATP Symplast includes translocation through plasmodesmata. Bakane disease of rice was found by Hori (1918) to be caused due to Gibberella fujikuroi. None of the options is correct Option (c) may be correct if statement be read as "Potassium readily moibilisation" instead of "potassium readily immobilisation.
Which one of the following is wrong statement
Phosphorus is a constituent of nucleic acids both DNA and RNA but absent in cell membranes and cell proteins.
For its activity, carboxypeptidase requires [2012M]
Carboxypeptidase is an exopeptidase enzyme secreted by the pancreas that acts only on the peptide linkage of a terminal amino acid containing a free carboxyl group. Zinc is a cofactor for carboxypeptidase. In digestion carboxypeptidase, requires zinc for its protein degrading action.
Read the following four statements (A-D).
(A) Both, photophosphorylation and oxidative phosphorylation involve the uphill transport of protons across the membrane.
(B) In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth.
(C) Stamens in flowers of Gloriosa and Petunia are polyandrous.
(D) Symbiotic nitrogen-fixers occur in the free-living state also in soil.
Q. How many of the above statements are correct? [2012M]
Symbiotic nitrogen-fixing bacteria and Cyanobacteria are found in association to plant. The most common symbiotic bacteria is Rhizobium.
In dicot stem, the cambium present between xylem and phloem in vascular bundles is called fascicular or intrafascicular cambium. Besides this some cells of medullary rays also become meristematic and called interfascicular cambium.
For its action, nitrogenase requires [2012M]
Nitrogenases are 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.
The first stable product of fixation of atmospheric nitrogen in leguminous plants is : [NEET 2013] (a) (b) (c)
Ammonia is first stable compound produce in fixation of atmospheric nitrogen in leguminous plant. A molecule of nitrogen is change into two molecules of ammonia. It requires 16 ATP, a source of electron donor ferredoxin, hydrogen donor NADPH or FMNH2 and dinitrogenase enzyme.
Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N2) to the atmosphere? [NEET Kar. 2013]
In the global nitrogen cycle, bacterial denitrification is recognised as important process that converts fixed nitrogen to atmospheric nitrogen gas, N2. In marine nitrogen cycle, anaerobic oxidation of ammonium coupled to nitrate reduction, contributes substantially to N2–production in marine sediments.
Which of the following elements is a constituent of biotin? [NEET Kar. 2013]
Biotin, also known as vitamin H, is a water-soluble B-vitamin. It is a coenzyme for carboxylase enzymes, involved in the synthesis of fatty acids, isoleucine, valine and in gluconeogenesis. Sulphur is a constituent of biotin.