Tag: bacteria; benefits and harmful effects

Superbugs is a term used to describe strains of bacteria that are resistant to the majority of antibiotics commonly used today. These resistant bacteria can cause pneumonia, urinary tract infections, skin infections and many other diseases that are difficult to treat and may be fatal.

An anaerobic organism or anaerobic bacteria is any organism that does not require oxygen for growth. It may react negatively or even die if oxygen is present. Mitochondria, Golgi body and ER are organelles of eukaryotic organisms. Since anaerobic bacteria is prokaryotic, they are absent in anaerobic bacteria.

Denitrifying bacteria convert nitrates in the soil to free atmospheric nitrogen, nitrogen-fixing bacteria are heterotrophs.

Anabaena belongs to the family of filamentous cyanobacteria that is known for its nitrogen fixing ability. While these exists as a plankton, it is known to form symbiotic relationships with the water fern Azolla and are found growing together at the surface of streams and ponds on temperate and tropical regions.
Therefore, the correct answer is option A.

The antibiotics are substances produced by the natural metabolic processes of spore forming aerobic bacteria and fungi as their natural defense against other microorganisms. Among bacteria and fungi, bacterial genera outnumber the fungal genera in production of antibiotics. The highest numbers of antibiotics are derived from bacterial genera Streptomyces and Bacillus and fungal genera Penicillium and Cephalosporium. This makes option A correct. Viruses do not perform any metabolic activity outside the host and hence, do not produce any antimicrobial agents. Angiosperms are most developed flowering plants that have number of adaptation to make them less susceptible for competition for food and space; they do not produce antibiotics. Thus, the correct answer is option is A.

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.