Tag: bacteria

Nitrogen fixing bacteria like rhizobium lives in symbiotic relationship with legumes.

Under optimum condition and temperature, most of the bacteria divides at interval of 20 minutes and this time is called their generation time. This is the time in which one bacterial cell divides and forms two cells. This is also known as the doubling time. 

The plasmid is an extrachromosomal material in bacteria and used as a carrier DNA because it has antibiotic resistance gene which makes it easy to isolate the transformed cell with the desired insert in it.

Azotobacter has a wide variety of metabolic abilities, including the unusual ability to fix atmospheric nitrogen as they produce nitrogenase enzyme and convert it to ammonia. They are free living in soil and do not associate as symbionts. 

Fermentation is a process of anaerobic respiration that converts sugar to acids, gasses or alcohol. It occurs in yeast and bacteria, but also in oxygen-starved muscle cells, as in the case of lactic acid fermentation. The food processing industry depends on this phenomenon for deriving a variety of edible products and beverages. As viruses are the acellular organism, they do not follow respiration. Protista are the eukaryotic unicellular and respire like animals. Thus, the correct answer is option D.

Some bacteria can fix atmospheric nitrogen, e.g., Azotobacter and Clostridium, while others convert ammonia into nitrate, e.g., Nitrosomonas.
A biogeochemical cycle or substance turnover or cycling of substances is a pathway by which chemical nutrients like carbon, oxygen, nitrogen, phosphorus, calcium, and water etc move through both biotic and abiotic compartments of earth. All of these are required to carry out basic life processes as these processes supply with energy and nutrients. Thus, the correct answer is option D.

Cyanobacteria, which have "symbiotic" relationships with cycads are in the order Nostocales. Anabaena cycadeae is a blue green algae (BGA) commonly found in the coralloid roots of cycads. At first, the cycad sprouts without any cyanobacterium. Coralloid roots are formed soon after the primary root.
So answer is - 'Cycas'.

Heterotrophic bacteria require an organic carbon source for growth (i.e., they derive energy and carbon from organic compounds). Economically important uses of heterotrophic bacteria are:

1. They enhance the fertility of the soil by nitrogen fixation.
2. Production of curd and yogurt from milk, cheese, butter, wine
3. Production of antibiotics
4. They form an essential part of biogeochemical cycles during which they release essential elements, such as nitrogen and carbon for recycling.
5. Cleaning of oil spills

Bacteria which directly convert atmospheric nitrogen into nitrogen compounds are called nitrogen fixing bacteria. They could be symbiotic or free- living like Rhizobium and Azotobacter respectively.
So answer is -'Nitrogen fixing bacteria'.

A chemoorganotroph is an organism, that obtains energy from the oxidation of reduced organic compounds. The list of compounds from which chemoorganotrophic organisms can generate energy and their sources of carbon is very long, making these microorganisms extremely versatile. Two mechanisms for energy conservation are known for chemoorganotrophs: fermentation and respiration.
So answer is - 'Chemoorganotrophs'.