Biological Classification Test - 11

A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi in a symbiotic relationship. The combined lichen has properties different from those of its component organisms.

A bacteriophage is a virus that infects and replicates within a bacterium.

Except bacteriophage, all possess cellular structure.

Viroids are smaller than viruses and caused potato spindle tuber disease. It was found to be a free RNA; it lacked the protein coat that is found in viruses, hence the name viroid. The RNA of the viroid was of low molecular weight.

The name virus that means venom or poisonous fluid was given by Pasteur. They are inert outside specific host and living inside the host cell. Viruses are obligate parasites.

The virus in which genetic material is RNA are called retrovirus. In this virus reverse transcription takes place to form DNA that synthesis proteins.

Three kingdom or domain system of classification do not includes viral domain. Virus were discovered after invention of electron microscope so, they were not the part of living world.

Virus consists of genetic material (DNA or RNA) surrounded by protein capsules. They are of different shapes and size. Polymyelitis virus is cubical in shape.

Mycoplasmas are group of organism that lack cell wall and are smallest living organisms. They can survive without oxygen. Mycoplasmas are also called as PPLO (pleuro pneumonia like organism).

Euglena is photosynthetic as well as saprophytic organism. It contain chlorophyll for photosynthesis and can absorbs food from dead and decaying materials.