Biology ยท 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

Which of the following is an example of a microbe that can be used in bioremediation?

  1. Pseudomonas

  2. Bacillus

  3. Rhizobium

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

Pseudomonas is a genus of bacteria that can be used in bioremediation, a process that uses microorganisms to clean up contaminated environments.

Multiple choice

What is the term for the practice of growing crops in a symbiotic relationship with nitrogen-fixing bacteria?

  1. Nitrogen fixation

  2. Mycorrhizae

  3. Rhizobia

  4. Leguminous crops
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Leguminous crops are plants that have a symbiotic relationship with nitrogen-fixing bacteria, which convert atmospheric nitrogen into a form that can be used by plants.

Multiple choice

What is the main mechanism by which Microbial Enhanced Oil Recovery (MEOR) techniques work?

  1. By injecting microorganisms that produce gases, acids, or solvents to enhance oil recovery

  2. By injecting microorganisms that increase the viscosity of the oil

  3. By injecting microorganisms that reduce the surface tension of the oil

  4. By injecting microorganisms that alter the wettability of the reservoir rock
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

MEOR techniques work by injecting microorganisms that produce gases, acids, or solvents into the reservoir, which can alter the properties of the oil or reservoir rock, leading to improved oil recovery.

Multiple choice

Which of the following is NOT a type of biofertilizer?

  1. Rhizobia

  2. Azospirillum

  3. Urea

  4. Phosphate-solubilizing bacteria
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Urea is a synthetic nitrogen fertilizer, not a biofertilizer.

Multiple choice

What is the primary mechanism by which rhizobia bacteria benefit legumes?

  1. Nitrogen fixation

  2. Phosphorus solubilization

  3. Potassium mobilization

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

Rhizobia bacteria form symbiotic relationships with legumes, enabling them to fix atmospheric nitrogen and convert it into a usable form for the plant.

Multiple choice

Which of the following is NOT a suitable cover crop for nitrogen fixation?

  1. Legumes (e.g., clover, alfalfa)

  2. Grasses (e.g., rye, wheat)

  3. Crucifers (e.g., mustard, radish)

  4. Corn
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Corn is not a suitable cover crop for nitrogen fixation, as it does not have the ability to convert atmospheric nitrogen into a usable form.

Multiple choice

What is the role of bacteria in biogas production?

  1. They generate heat for the process.

  2. They produce oxygen for the process.

  3. They break down organic matter.

  4. They absorb nutrients from the feedstock.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bacteria play a crucial role in biogas production by breaking down organic matter into simpler compounds through anaerobic digestion.

Multiple choice

Which of the following is not a common type of microorganism used in bioremediation?

  1. Bacteria

  2. Fungi

  3. Algae

  4. Protozoa
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Protozoa are not commonly used in bioremediation because they are not as effective at degrading contaminants as bacteria, fungi, and algae.

Multiple choice

What is the role of methanogenic bacteria in anaerobic digestion?

  1. They convert organic matter into methane

  2. They convert methane into carbon dioxide

  3. They produce hydrogen sulfide

  4. They produce ammonia
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Methanogenic bacteria are responsible for converting organic matter into methane during anaerobic digestion.

Multiple choice

What is the largest known bacterium?

  1. Thiomargarita namibiensis

  2. Escherichia coli

  3. Bacillus subtilis

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

Thiomargarita namibiensis is a sulfur-oxidizing bacterium that can grow up to 0.75 millimeters in diameter, making it visible to the naked eye.

Multiple choice

What is the role of nitrogen-fixing bacteria in the nitrogen cycle?

  1. Converting atmospheric nitrogen into ammonia

  2. Decomposing organic matter

  3. Producing oxygen through photosynthesis

  4. Fixing carbon dioxide into organic compounds
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nitrogen-fixing bacteria play a crucial role in the nitrogen cycle by converting atmospheric nitrogen into ammonia, which can be used by plants for growth.

Multiple choice

What is the process by which bacteria produce energy from organic compounds in the absence of oxygen?

  1. Aerobic respiration

  2. Anaerobic respiration

  3. Photosynthesis

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

Anaerobic respiration is a process by which bacteria break down organic compounds to produce energy without using oxygen.

Multiple choice

What is the term used to describe the ability of some plants to form symbiotic relationships with beneficial microorganisms that help them compete with weeds?

  1. Mycorrhizae

  2. Rhizobia

  3. Endophytes

  4. Nitrogen-fixing bacteria
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mycorrhizae are symbiotic relationships between plants and fungi that help the plant absorb nutrients from the soil, which can give them an advantage over weeds in nutrient-poor environments.

Multiple choice

What is the primary role of lichens in the nitrogen cycle?

  1. Nitrogen fixation

  2. Nitrification

  3. Denitrification

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

Lichens play a crucial role in the nitrogen cycle by fixing atmospheric nitrogen and converting it into a usable form for plants and other organisms. This process is essential for maintaining the balance of nitrogen in ecosystems.

Multiple choice

Which species of bacteria is found in the Sundarbans?

  1. Escherichia coli

  2. Salmonella

  3. Staphylococcus

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

Escherichia coli is a bacteria species found in the Sundarbans.