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 biology air and atmosphere natural cycles and resources constituents of air medicinal use of microorganism component of air - nitrogen

Natural fixation of nitrogen takes place through a non-biological process called ___________.

  1. artificial fixation

  2. nitrogen fixation by lightening

  3. industrial fixation

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

In non biological fixation of nitrogen when the plant dies the fixed nitrogen is released making it available to other plants and this helps to fertilize the soil. The great majority of legumes have this association but a few genera do not. In farming practices fields are rotated through various crops like clover and buckwheat which are known as green manure.

Multiple choice biology air and atmosphere natural cycles and resources constituents of air medicinal use of microorganism component of air - nitrogen

Nitrogen fixation means:

  1. manufacture of nitrogen

  2. liquefication of nitrogen

  3. conversion of nitrogen into nitric acid

  4. conversion of atmospheric nitrogen into useful compounds

  5. mixing of nitrogen with other elements
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nitrogen fixation is a process in which nitrogen(N2) in the atmosphere is converted into ammonia (NH3) and useful compounds. Atmospheric nitrogen or molecular dinitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds.

So the answer is D.

Multiple choice botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

Two bacteria found to be very useful in genetic engineering experiment are

  1. Nitrosomonas and Klebsiella

  2. Escherichia and Agrobacterium

  3. Nitrobacter and Azotobacter

  4. Rhizobium and Diplococcus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Till today, the most important in genetic engineering of plants has been the Ti plasmid of soil bacterium, Agrobacterium tumefaciens. E.Coli  has been extensively used as "work horse" for genetic engineering e.g., production of humulin, somatotropin. E. coli is one of the most thoroughly studied of all living things. It is a favorite organism for genetic engineering as cultures of it can be made to produce unlimited quantities of the product of an introduced gene. Several important drugs (insulin, for example) are now manufactured in E. coli. Thus, option B is correct. Nitrosomonas, Klebsiella, Nitrobacter, Azotobacter, Rhizobium and Diplococcus are not used in genetic engineering.

Multiple choice botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

Two bacteria most useful in genetic engineering are

  1. Rhizobium and Azotobacter

  2. Escherichia and Agrobacterium

  3. Rhizobium and Diplococcus

  4. Nitrosomonas and Klebsiella
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Escherichia coli and Agrobacterium tumefaciens are the most widely used bacteria in genetic engineering for cloning and plant transformation, respectively.

Multiple choice biology cell and cell organelles cell membrane and cell wall cell wall cell division in embryo development

Which one of the following is wrong statement.

  1. Anabaena and Nostoc are capable of fixing nitrogen- in

    free living state also

  2. Root nodule forming nitrogen fixers live as aerobes

  3. Phosphours is a constituent of all members ,certain

    nucleic acids and all proteins

  4. Nitrosomonas and Nitrobacter are chemoautotrophs
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Anabaena and Nostoc are also free-living nitrogen fixers.
Root nodule forming nitrogen fixers enzyme (nitrogenase) works only under the anaerobic condition.
Phosphorus is a constituent of cell membranes as a phospholipid, in nucleic acid as phosphate group and proteins are rich in phosphorus.
Nitrosomonas and Nitrobacter play an important role in nitrification. They are chemoautotrophs.
So the correct answer is 'Root nodule forming nitrogen fixers live as aerobes under free-living conditions'
Multiple choice biology aids to health antibiotics and their uses common health care methods immunization, treatment and antibiotics first aid

Which of the following statement is correct?

  1. Activated sludge is digested by anaerobic bacteria to produce marsh gas.

  2. Aspergillus niger produces cyclosporin A.

  3. Fleming, Chain and Florey were awarded Nobel Prize for discovering penicillin.

  4. BOD is amount of oxygen produced by bacteria during decomposition.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Alexander Fleming, Howard Florey, and Ernst Chain were jointly awarded the 1945 Nobel Prize in Physiology or Medicine for the discovery of penicillin and its curative effect in various infectious diseases.

Multiple choice evs deficiency diseases need for nutrients nutrients needed by the body balanced diet and malnutrition food for health nutrition and its deficiency nutrition and its need

Plants require nitrogen along with carbohydrates. This nitrogen can be obtained by

  1. Rhizobium

  2. Vibrio

  3. Salmonella

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

Rhizobium is a nitrogen-fixing bacteria found in symbiotic association with the root nodules of leguminous plants. 

For nitrogen fixation rhizobium needs an oxygen-free environment because oxygen acts as a poison and so it forms the association because the root nodules contain leg hemoglobin which is an oxygen scavenger. 
In return the plant gets Nitrogen.
So, the correct option is 'Rhizobium'

Multiple choice biology sustainable agriculture patterns of cropping rotation of crops cropping patterns common irrigation systems

Which of the following biofertilizer bacteria is a phosphorus solubilizer?

  1. Azotobacter

  2. Azospyrillum

  3. Basillus & Pseudomonas

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

A.Azotobacter is a genus of usually motile, oval or spherical bacteria . It has several metabolic capabilities, including atmospheric nitrogen fixation by conversion to ammonia.
B.Azospirillum bacteria can promote plant growth. 
C.The bacteria Basillus  & Pseudomonas convert non labile Phosphorous  through either inorganic Phosphorous solubilizing or organic Phosphorous mineralization processes.
D.Cyanobacteria, also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen.
So the correct option is ' Bacillus  & Pseudomonas ' .

Multiple choice botany strategies for enhancement in food production balanced diet food production and microbes plant breeding for food production

Which non-toxic, fast growing cyanobacterium is cultivated in tanks as a protein-rich animal feed?

  1. Stigonema

  2. Spirulina

  3. Nostoc

  4. Oscillatoria
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Spirulina represents a biomass of cyanobacteria (blue-green algae) that can be consumed by humans and other animals. The two species are Arthrospira platensis and A. maxima. Cultivated worldwide, Arthrospira is used as a dietary supplement or whole food. It is also used as a feed supplement in the aquaculture, aquarium, and poultry industries. Spirulina was found in abundance at Lake Texcoco by French researchers in the 1960s, but no reference to its use was made by the Aztecs as a daily food source after the 16th century, probably due to the draining of the surrounding lakes for agriculture and urban development. As an ecologically sound, nutrient-rich, dietary supplement, spirulina is being investigated to address food security and malnutrition, and as dietary support in long-term space flight or Mars missions. Its interest for food security is for lower land and water needs to produce protein and energy than required for livestock as meat sources.
So the correct option is 'spirulina'.
Multiple choice botany root - external morphology root system in plants modifications of root root modifications

The association of Nitrogen fixing bacteria (nodule bacteria) with leguminous roots is known as 

  1. Saprophytism

  2. Symbiosis

  3. Epiphytism

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

Symbiosis is a type of association of dissimilar organisms of their mutual advantage, e.g., association of nitrogen-fixing bacteria (nodule bacteria) with leguminous roots. The bacteria, inhabiting nodules on roots manufacture compounds from the nitrogen of the air, which becomes available to the plant. From the plant, bacteria obtain carbohydrates and other food materials.

Multiple choice botany root - external morphology root system in plants modifications of root root modifications

Baderoids are

  1. Enlarged non-motile cellular bacteria Rhizobium

    leguminosarum in root nodules of legumes

  2. A bacterial cell infected with viruses

  3. A motile bacterium

  4. Nitrosomonas bacteria in soil
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bacteroid : Symbiotic bacteria Rhizobium leguminosarum in leguminous plants e.g., gram, pea etc. in their roots nodules produce Leg haemoglobin  this whole Bacteria + Leg haemoglobin + Polyploide  cells of roots is called as bacteroid.