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

In which of the following processes are the species of Pseudomonas, Alkaligenes and Bacillus involved?

  1. Nitrification

  2. Ammonification

  3. Denitrification

  4. N2 fixation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Species of Pseudomonas, Alkaligenes and Bacillus are involved in the process of denitrification. Their activities result in substantial losses of nitrogen into the atmosphere, roughly balancing the amount of nitrogen fixation that occurs each year.

Multiple choice

Diazotrophs is the name given to a group of organisms. Who are these organisms and what is the function of these organisms?

  1. They are prokaryotes, which use N2 as an energy source.

  2. They are prokaryotes involved in nitrogen fixation.

  3. They are eukaryotes, which are involved in N2 fixation.

  4. Diazotrophs are prokaryotes involved in denitrification.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Diazotrophs are specific group of prokaryotes involved in the process of nitrogen fixation.

Multiple choice

Where is leghaemoglobin produced?

  1. In bacterial cell

  2. In roots of a plant

  3. In nodules

  4. In root hairs
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Leghaemoglobin is found only in the nodules; leghaemoglobin may regulate the supply of oxygen to the nodule tissues in the same way as haemoglobin regulates the supply of oxygen to mammalian tissues.

Multiple choice

Match the following:

 
Leguminous plant Symbiotic bacteria
1. Pea a. R. melioti
2. Soya bean b. R. phaseoli
3. Alfalfa c. R. japonicum
4. Urad d. R. leguminosarum
  1. 1. Pea a. R. phaseoli
    2. Soya bean d. R. leguminosarum
    3. Alfalfa b. R. phaseoli
    4. Urad c. R. japonicum
  2. 1. Pea d. R. leguminosarum
    2. Soya bean c. R. Japonicum
    3. Alfalfa a. R. melioti
    4. Urad b. R. phaseoli
  3. 1. Pea a. R. melioti
    2. Soya bean d. R. leguminosarum
    3. Alfalfa c. R. japonicum
    4. Urad b. R.phaseoli
  4. 1. Pea b. R. phaseoli
    2. Soya bean c. R. japonicum
    3. Alfalfa d. R. leguminosarum
    4. Urad a. R. melioti
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is a correct match. Pea has R. leguminosarum in root nodules, Soya bean has R. japonicum in root nodules, Alfalfa has R. melioti in root nodules and Urad has R. phaseoli in root nodules.

Multiple choice

Which of the following is a culture medium for a genus of bacteria that colonise the mucosal surfaces of many animals?

  1. Eaton's agar

  2. Thayer-Martin agar

  3. Bismuth sulfite agar

  4. Bordet-Gengou agar

  5. Löwenstein–Jensen medium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because Thayer-Martin agar, a Mueller-Hinton agar with 5% chocolate sheep blood and antibiotics, is used for culturing and primarily isolating pathogenic Neisseria bacteria.

Multiple choice

Rod shaped bacteria are called

  1. vibrio

  2. bacillus

  3. cocci

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bacillus is the correct term for rod-shaped bacteria. Vibrio are comma-shaped, cocci are spherical, so bacillus specifically describes the elongated, cylindrical shape.

Multiple choice

What is the relation between rhizobium and leguminous plants?

  1. Symbiotic

  2. Parasitic

  3. Heterotrophic

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

Rhizobium and leguminous plants share a mutual relation with each other, benefiting each other and getting benefited from each other and the relation is known as symbiotic relation.