Tag: biogeochemical cycles - gaseous

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Questions Related to biogeochemical cycles - gaseous

Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

Nitrogen fixing bacteria- anabaena - are found in the plant ______

  1. Azolla leaves

  2. Cycas corolloid roots

  3. Anthoceros body

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Anabaena are the one type of cyanobacteria, present in the leaves of Azolla, Corolloid roots of Cycas, Anthoceros body. They perform symbiotic Nitrogen fixation.
So the correct option is 'All of these'.
Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

The biological process by which carbon is returned to its reservoir is

  1. photosynthesis

  2. denitrification

  3. carbon fixation

  4. cellular respiration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A. Photosynthesis is the process in which plants prepare their own food using carbon dioxide and water which are converted into glucose in the presence of sunlight along with the release of oxygen.
B. Denitrification is a process of reduction of nitrate into molecular nitrogen by denitrifying bacteria.
C. Carbon fixation is the reduction and incorporation of inorganic carbon into organic compounds.
D. Cellular respiration is a metabolic reaction in which energy is released from the breakdown of complex substances. Oxygen is used in respiration and carbon dioxide is released. Hence, carbon is returned to its reservoir through cellular respiration.
So, the correct answer is 'cellular respiration'.
Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

Which one of the following is a wrong statement ? 

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

  2. Nitrosomonas and Nitrobacter are chemoautotrophs

  3. Anabaena and Nostoc are capable of fixing nitrogen in free living state

  4. Root nodule forming nitrogen fixers live as aerobes under free living conditions
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A. Phosphorus is constituent of cell membranes in the form of phospholipids and also present in nucleic acids as phosphate in the sugar-phosphate backbone.
B. Nitrosomonas and Nitrobacter are nitrifying bacteria. These bacteria derive energy by oxidizing inorganic nitrogenous compounds. Hence, they are called chemoautotrophs.
C. Anabaena and Nostoc are cyanobacteria (also known as blue-green algae). They are free-living bacteria and can fix nitrogen because they have specialized cells called heterocysts with the help of which they can fix atmospheric nitrogen.
D. Root nodule forming nitrogen-fixing microbes live freely in the soil as aerobes. They form a symbiotic association with the roots of plants when some chemicals or factors are released by the plants. For example, Rhizobium.
Hence, statement A is incorrect.
So, the correct answer is 'Phosphorus is a constituent of cell membranes, certain nucleic acids, and all proteins'.
Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

The bacteria ______ supply natural manure to paddy fields.

  1. Azolla

  2. Anabaena

  3. Azotobacter

  4. Nostoc
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The bacteria Azolla supplies natural manure to the paddy fields. Azolla is a gliding pteridophyte, which contains as endosymbiont the nitrogen-settling cyanobacterium Anabaena azollae (Nostocaceae family). 
Generally developed in the Asian districts, Azolla is either consolidated into the dirt before rice transplanting or developed as a double product alongside rice. 
So, the correct answer is A.
Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

The ozone at ground level is primarily from__________ precursors

  1. Fossil fuel
  2. $CFC _{S}$

  3. Oxygen

  4. Methane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ground-level ozone is a secondary pollutant formed by the reaction of nitrogen oxides and volatile organic compounds in the presence of sunlight, both of which are primarily emitted by fossil fuel combustion.