Revision in one short imp topic biological classification Vi | NEET Short Notes

Revision in one short imp topic biological classification

Viruses

The viruses are acellular structures and therefore do not find a place in Whittaker’s five kingdom classification. They consist of nucleic acid (either DNA or RNA) that is surrounded by a protein coat. These viruses can grow and multiply only within a host cell. Viruses exist as crystals outside the host cell. They cause disease and severely damage the host. Examples of common viruses are the viruses that cause cold, flu, polio, AIDS, etc.



Viroids

They are the smallest known infectious structures and consist only of nucleic acid without a protein shell.



Lichens
They are known to be the symbiotic associations of algae and fungi. The pair of algae are autotrophic and synthesized and provide food. The mushroom pair offers protection and shelter.