Biology · Environmental Studies

Microbiology and Nitrogen Cycle

950 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/are example(s) of biofertilizers?

  1. Blue green algae
  2. Ammonium nitrate
  3. Azospirillium

  1. 1 and 2 only

  2. 1 and 3 only

  3. 2 and 3 only

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bio-fertilizers provide eco-friendly organic agro-input and are more cost-effective than chemical fertilizers. Bio-fertilizers such as Rhizobium, Azotobacter, Azospirilium and blue green algae (BGA) have been in use for a long time. Ammonium nitrate is an example of chemical fertilizer.

Multiple choice

Rhizosphere microflora represent

  1. atagonism

  2. mutualism

  3. commensalism

  4. protocooperation

  5. amensalism
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

It is where two species interact with each other beneficially without establishing a physical contact with each other. The rhizosphere is the zone surrounding the roots of plants in which complex relations exist among the plant, the soil microorganisms and the soil itself.

Multiple choice

Which of the following are free living aerobic asymbiotic nitrogen fixing bacteria? P. Azotobacter Q. Klebsiella R. Clostridium S. Rhizobium Select the correct answer using codes given below:

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. R and S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bacteria which convert atmospheric nitrogen into compounds of nitrogen are called nitrogen fixing bacteria. Azotobactor and klebsiella are examples of free living aerobic asymbiotic nitrogen fixing bacteria.

Multiple choice

Which of the following is a pair of non-motile bacteria?

  1. Helicobacter pylori and Nisseria gonorrhoeae

  2. Nisseria gonorrhoeae and Yersinia pestis

  3. Helicobacter pylori and Yersinia pestis

  4. Helicobacter pylori and Alcaligenes faecalis

  5. Yersinia pestis and Alcaligenes faecalis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nisseria gonorrhoeae is a coffee bean-shaped Gram-negative, non-motile bacteria. Yersinia pestis is a Gram-negative, rod-shaped, non-motile bacteria.

Multiple choice

Which of the following are facultative anaerobic Gram-negative bacteria?

  1. Bordetella pertussis and Mycobacterium tuberculosis

  2. Mycobacterium tuberculosis and Klebsiella pneumoniae

  3. Bordetella pertussis and Vibrio cholerae

  4. Klebsiella pneumoniae and Vibrio cholerae

  5. Klebsiella pneumoniae and Vibrio cholerae
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Klebsiella pneumoniae is a Gram-negative, facultative anaerobic, rod-shaped bacterium. Vibrio cholerae is a Gram-negative, facultative anaerobic, comma-shaped bacterium.

Multiple choice

Which of the following bacteria causes holoblight of beans?

  1. Pseudomonas salomonii

  2. Pseudomonas syringae

  3. Pseudomonas savastanoi

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

Pseudomonas syringae is a rod-shaped, Gram-negative bacterium with polar flagella which causes holoblight of beans. This bacterium produces a toxin which causes systemic chlorosis.

Multiple choice

Which of the following groups of bacteria are called gliding bacteria?

  1. Mycobacteria and Myxobacteria

  2. Mycobacteria and Cytophagales

  3. Myxobacteria and Cytophagales

  4. Cytophagales and Rickettsiae

  5. Rickettsiae and Chlamydiae
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Myxobacteria and Cytophagales are called gliding bacteria on the basis of their gliding mobility on solid surfaces.