Question

A cell biologist sterilizes his culture media by filtration. However, he is getting frustrated because his media is still contaminated with Mycoplasma!   He doesn't understand why? Which of the following might you use to explain to him why he keeps having this problem.  Check TWO Answers

		Mycoplasma are viruses, so they can pass through the pores of the filter.
		Mycoplasma are pleomorphic, and can therefore squeeze through the pores in filtration membrane.
		Mycoplasma do not have a cell wall, so so they are smaller in diameter than most bacteria that are trapped by filtration membranes.
		Mycoplasma form endospores, which are resistant to sterilization by filtration.
		Mycoplasma are very long, narrow, rod-shaped bacteria, so in the right orientation they can pass through the pores of the filter.

Answer 1

Ans : The two correct options are :

* Mycoplasma are pleomorphic, & can therefore squeeze through the pores in the filteration membrane.( They are pleomorphic, that is they can change their shape ranging from rod, ring like, globoid or filamentous & are ultrafilterable.)

* Mycoplasma do not have a cell wall, so they are smaller in diameter than most bacteria that are trapped by filteration membranes.( Lack of cell wall provides them elasticity to change their shape & resistance to antibiotics ,as antibiotics interferes with cell wall synthesis & Mycoplasma do not possess cell wall.)

Incorrect options are :

* Mycoplasma are viruses so they can pass through the pores of the filter (Mycoplasma are unicellular ,smallest, non motile prokaryotic bacteria)

* Mycoplasma forms endospores that are resistant to sterilization by filteration.(Mycoplasma are the bacteria, for which there are no prior claims of endospore formation)

* Mycoplasma are very long rod shaped bacteria, so in the right orientation they can pass through the pores of the filter.(Mycoplasma are the smallest bacteria ranging from 0.2 - 0.4 micor metre.)

Hope this will help you?