Question

What is wrong about mycoplasma?
a. They are called PPLO
b. They are pleomorphic
c. They are sensitive to penicillin
d. They cause diseases in plants

Answer 1

Hint: As there are a vast number of diverse organisms in our Earth, there is a need to classify them based on their cellular structure, mode of nutrition, etc. R.H.Whittaker proposed a Five kingdom classification namely Monera, Protista, Fungi, Plantae, Animalia. Earlier classification systems included bacteria, blue-green algae, fungi, mosses, ferns, gymnosperms and the angiosperms under “Plants”. Later the change was made as there are differences in cell number and composition.

Complete answer:
Kingdom Monera is divided into two groups namely Archaebacteria and Eubacteria. Under this kingdom the microorganisms reigned especially the bacteria which is present almost everywhere. Some examples are Coccus, Vibrio, Bacillus, etc.

Some bacteria have locomotory organs to move or swim from one place to another in search of food. Cyanobacteria or blue-green algae have chlorophyll and are photosynthetic autotrophs. Heterotrophic bacteria are the most abundant in nature as these are important decomposers.

The organisms which have a single cell without distinct organelles and nucleus are called prokaryotes. Mycoplasma is the organisms that are free living and the simplest of the prokaryotes. They lack cell walls and were discovered in the pleural fluid of the animals who were suffering from pleuropneumonia and they are called PPLO which stands for Pleuropneumonia like organisms).

They are pleomorphic as they do not have a cell wall. They can even survive without oxygen. As the cell wall is absent the outer boundary is formed by the plasma membrane.
They are not sensitive to penicillin as they do not have a cell wall and they are pathogenic in animals and plants causing pleuropneumonia disease.

Hence, The correct answer is option (C).

Note: The term Mycoplasma was first used by Albert Frank. Mycoplasma is spread to other people by coughing and sneezing through air. It causes pneumonia, sore throat, and bronchitis.
The mode of nutrition can be parasitic or saprotrophic. The species of Mycoplasma are the smallest among the bacterial cells.