Tag: bio-geo chemical cycles in nature

Quizzes (5) Questions (95)

Questions Related to bio-geo chemical cycles in nature

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

The bacteria present in root nodules of leguminous plants that fix the atmospheric nitrogen is

  1. Rhizobium

  2. Blue-green algae

  3. Nitrifying bacteria

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

Rhizobium is a bacterium found in the root nodules of leguminous plants. It induces the formation of special structures called nodules inside which it fixes atmospheric nitrogen. It does this with the help of nitrogenase enzyme that converts of nitrogen to ammonium that is an important factor required for plant growth. In turn, the bacterium receives shelter from the plant. Thus the correct answer is option A.

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Oxidation of Ammonia into nitrite is performed by


(a) Nitrosomonas (b) Nitrosococcus (c) Nitrobacter (d) Nitrospira

  1. a, b

  2. b, c

  3. c, d

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

Oxidation of Ammonia to nitrite is performed by two groups of bacteria. Nitrosomonas and Nitrosocossus are examples of bacterias which perform the oxidation of ammonia to nitrite.

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Nitrifying bacteria convert the

  1. Nitrates into nitrites

  2. Nitrites into nitrates

  3. Ammonium salts into nitrates

  4. Ammonium salts into amino acids
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Nitrification is a process of conversion of ammonium salts to nitrites and nitrites to nitrates. The bacteria that carry out this process are called as nitrifying bacteria. Nitrosomonas, Nitrosospira, Nitrosococcus convert ammonia into nitrites. Nitrobacter, Nitrospina, Nitrococcus convert nitrites into nitrates.

Thus, the correct answer is 'Ammonium salts into nitrates.'

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

In excess, $C{O} _{2}$

  1. Accelerates growth

  2. Does not influence growth

  3. Inhibits growth

  4. Slows down growth
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Atmospheric carbon dioxide is used by plants to produced food. Due to industrialization, large amount of carbon dioxide is released in the atmosphere. This CO$ _2$ provides nutrient source to certain plants. However, excess amount of CO$ _2$ inhibits growth in plants. It inhibits nitrate assimilation in certain plants. It basically inhibits absorption of nitrogen.

Thus, the correct answer is option C.

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Nitrosomonas and Nitrobacter convert

  1. Carbon dioxide to carbohydrates

  2. Ammonium ion into nitrate

  3. Nitrate ion into nitrogen molecule

  4. Nitrogen into nitrate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nitrification is a process of conversion of ammonium ions to nitrites and nitrites to nitrates. The bacteria that carry out this process are called as nitrifying bacteria. Nitrosomonas, Nitrosospira, Nitrosococcus convert ammonia into nitrites. Nitrobacter, Nitrospina, Nitrococcus convert nitrites into nitrates.

Thus, the correct answer is 'Ammonium ion into nitrate.' 

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

The common nitrogen fixer organism in paddy fields is

  1. Azospirillum

  2. Oscillatoria

  3. Frankia

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

Atmospheric nitrogen is not available to plants. There are certain nitrogen fixing bacteria which converts atmospheric nitrogen into ammonium compounds and make it available to the plants. Examples include Azotobacter, Frankia, Rhizobium, Azospirillum. Out of these, Azospirillum is widely used as nitrogen fixer organism in paddy fields. It is used as biofertilizer in rice fields. It promotes the plant growth.

Thus, the correct answer is 'Azospirillum.'

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Nitrite is changed to nitrate by

  1. Nitrobacter

  2. Nitrosomonas

  3. Clostridium

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

There are two steps in nitrification process by which ammonia is converted into nitrite and nitrite into nitrate. The bacteria that convert ammonia to nitrites include Nitrosomonas, Nitrosospira and the bacteria that convert nitrites to nitrates include Nitrobacter, Nitrospina. 

Thus, the correct answer is 'Nitrobacter.'

Multiple choice zoology bio-geo chemical cycles in nature nitrogen cycle biogeochemical cycles - gaseous nutrient cycles

Carefully read the following reactions carried out by nitrifying bacteria. Identify the statement about these equations which is not true.
2NH$ _3$+3O$ _2$ $\rightarrow$ 2NO$^- _2$ +2H$^+$ +2H$ _2O$ ---- (I)
2NO$^- _2$+O$ _2$ $\rightarrow$ 2NO$^- _3$ ---- (II)

  1. Step I is carried out by Nitrosomonas or Nitrosococcus

  2. Step II is carried out by Nitrobacter

  3. Both the steps I and II can be called nitrification

  4. Both the steps occur only in photoautotrophs
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
I) In the first step, ammonia is oxidised to nitrites by the action of nitrosomonas and nitrococcus bacteria.
II) In the second step, nitrate is further oxidised to nitrate with the help of nitrobacter and nitrocystis.
Both the reaction is involved in the process of nitrification. These nitrifying bacteria involved are called chemoautotrophs.
So the correct answer is 'Both the steps occur only in photoautotrophs'.