Biology ยท 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 statements is/are correct?

a. Carbon is an essential constituent of different organic compounds, such as amino acids, nucleic acids, proteins, vitamins and pigments. b. Only a few types of organisms, like certain species of soil bacteria and blue green algae, are capable of utilising carbon directly in its gaseous form. c. Carbohydrates that are decomposed by microorganisms, then get oxidised into carbon dioxide and are returned to the atmosphere.

  1. a only

  2. b only

  3. c only

  4. a and b

  5. a, b and c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer as this statement is correct.

Multiple choice

Aerotolerant anaerobes in culture media are _________.

  1. bacteria which have anaerobic growth, but continue in presence of oxygen

  2. bacteria which have only aerobic growth and oxygen required

  3. bacteria which have both aerobic and anaerobic growth and have greater growth in presence of oxygen

  4. bacteria which have only anaerobic growth, but cease in the presence of oxygen

  5. bacteria which have only aerobic growth, but oxygen is required in low concentration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aerotolerant anaerobes : Bacteria which have anaerobic growth, but continue in presence of oxygen

Multiple choice

What is the component which chemically removed molecular oxygen, that might interfere with the growth of anaerobes in a growth media?

  1. Seaweed extract (polysaccharide)

  2. Biotin

  3. Sodium Thioglycolate

  4. Oxyrase

  5. Both (3) and (4)
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Correct answer. Sodium Thioglycolate combines with dissolved O2 to deplete O2 in media. Oxyrase is a bacterial respiratory enzyme that can be put in media; it combines O2 with H+ to remove O2 by forming H2O and turns the petri dish into a mini-anaerobic chamber