Biology · Environmental Studies

Microbiology and Nitrogen Cycle

1,029 Questions

This hub focuses on microbiology and the nitrogen cycle, covering essential concepts about bacteria and soil microbes. Topics include nitrogen fixation, bacterial structures, and soil microbial processes. These concepts are frequently tested in general science sections of various competitive exams.

Nitrogen fixing bacteriaGram-positive bacteriaBacterial flagellaDenitrifying bacteriaAmmonia conversion processBacterial resting spores

Microbiology and Nitrogen Cycle Questions

Multiple choice

Based on their properties, match the “Genera” in Group 1 with those in Group 2

Group 1| Group 2| | P. Bacillus| 1. Sarcina| | Q. Neisseria| 2. Azotobacter| | R. Rhizobiurn| 3. Hyphomicrobium| | S. Caulobacter| 4. Clostridium|

  1. P - 4, Q - 1, R - 2, S - 3

  2. P - 4, Q - 1, R - 3, S - 2

  3. P - 2, Q - 4, R - 1, S - 3

  4. P - 1, Q - 4, R - 2, S - 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bacillus (Clostridium - related), Neisseria (Sarcina - related), Rhizobium (Azotobacter - related), Caulobacter (Hyphomicrobium - related).

Multiple choice botany plant breeding biotechnology for improved food quality plant breeding for food production

Beta-carotene can be induced in the golden rice by a process known as

  1. Biological nitrogen fixation

  2. Biofortification

  3. Bioremediation

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Biofortification is the method in which the food is added or supplemented with the required nutrients. The staple crop like rice is fortified to produce the precursor of vitamin A. Golden rice is the transgenic rice in which beta-carotene synthesizing gene psy and crtl are incorporated by the help of genetic engineering. Beta-carotene is the precursor of the vitamin A. The consumption of the golden rice can help to prevent the deficiency disorders due to less intake of vitamin A. 

Thus, the correct answer is option B. 

Multiple choice

What is the most common type of bacteria?

  1. spherical shaped

  2. rod shaped

  3. cork-screw shaped

  4. square shaped
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bacilli are rod-shaped bacteria and are the most common form of bacteria found in nature.

Multiple choice biology respiration in living organisms breathing in plants mode of respiration in plants process of respiration

Which one of the following organism may respire in the absence of oxygen?

  1. Azotobacter

  2. Clostridium

  3. Rhizobium

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

Azotobacter is a genus of free-living nitrogen-fixing bacteria that are typically aerobic, but many organisms like Clostridium are obligate anaerobes. However, the question asks which 'may' respire in the absence of oxygen; Clostridium is a classic example of an obligate anaerobe, but Azotobacter is often cited in specific contexts of facultative or microaerophilic capability in curriculum materials.

Multiple choice factors affecting respiration living organisms and energy production life processes in living organisms- part 1 respiration biology

Which one of the following organisms may respire in the absence of oxygen?

  1. Azotobacter

  2. Clostridium

  3. Rhizobium

  4. Lactobacillus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Obligate anaerobic beings are those that cannot survive when oxygen is present. Some fungi, some bacteria (like the agent of botulism -Clostridium botulinum, and the agent of tetanus- Clostridium tetani) and some protozoans are examples of obligate anaerobes.

Multiple choice biology micro - organism useful actions of algae introduction to algae algae

Which type of algae are helpful in nitrogen economy?

  1. Green algae

  2. Blue green algae

  3. Red algae

  4. Brown algae
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The majority of blue-greens are aerobic photoautotrophs, their life processes require only oxygen, light and inorganic substances. At the onset of nitrogen limitation, during bloom conditions, certain cells in Anabaena evolve into heterocysts, which convert nitrogen gas into ammonium, which is then distributed to the neighboring cells of a filament. In addition, blue-greens that form symbiotic (mutually beneficial) relationships with a wide range of other life forms, can convert nitrogen gas into ammonium.

Therefore, the correct answer is option B.

Multiple choice biology micro - organism useful actions of algae introduction to algae algae

Which of the following blue-green algae helps in the formation of biofertilizers?

  1. Anabaena

  2. Ocillataria

  3. Nostoc

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • All of the above organisms are the genus of cyanobacteria which are used for fixing nitrogen in the nitrogen cycle.
  • So the correct answer is 'All of the above'.
Multiple choice biology reproduction in animals story of dolly, the clone sheep story of dolly, the clone process of cloning

'Nif' gene for nitrogen fixation in cereal crops like wheat, jowar etc., is introduced by cloning.

  1. Rhizobium meliloti

  2. Bacillus thuringiensis

  3. Rhizopus stolonifer

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

Rhizobium meliloti is a nitrogen-fixing bacterium often studied for its nif genes, which are involved in the nitrogen fixation process.

Multiple choice biology interdependence of organism and the environment natural cycles and resources constituents of air medicinal use of microorganism

Identify correct pairs from the following.

(P) Rhizobium$\longrightarrow$ Nitrogen fixation
(Q) Clostridium$\longrightarrow$ Bakery products
(R) Penicillium$\longrightarrow$ Production of antibiotics
(S) Yeast $\longrightarrow$Food poisoning

  1. P and Q

  2. R and P

  3. S and R

  4. Q and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Rhizobium is a nitrogen fixation bacteria found in soil.
  • Penicillium is an antibiotic used for making medicines and antibiotics.

So, the correct option is 'R and P'.