Question

Why are viruses obligate intracellular parasites?

Answer 1

Hint: Viruses are unique when compared to other microorganisms. The term obligate intracellular parasites means that the organism cannot reproduce independently and cannot carry out its function without the aid of another living cell. They need to get inside other cellular organisms to reproduce, that is they need a host cell for replication.

Complete answer:
Viruses possess characteristics of both living and nonliving things. Outside another living cell it acts as a non-living organism, whereas, inside a living cell, it shows characteristics of a living organism. Due to this nature, viruses are often referred to as the ‘Biologists puzzle’.
Viruses do not have the capacity to reproduce independently. They need to attach themselves to a host cell, get engulfed by that living cell, manifest its proteins to the cellular DNA and continue this process. Viruses do not have their own metabolic processes to produce energy or make proteins, they rely on other cells to do these crucial functions. This is why viruses are called obligate intracellular parasites.

Additional information:
A virion is a complete viral entity made up of an exterior protein matrix called capsid and a nucleic acid core. Viroids are tiny pathogens that cause diseases. They are made entirely of a circular RNA molecule. Viroids do not have a protein covering, unlike viruses.

Note:
Parasites are organisms that depend on other living organisms and cause harm to them. Viruses are obligate intracellular parasites which means they need to live inside a host cell to perform their basic functions. They are considered critical because they trigger a wide range of diseases in human and other living organisms and cause illness and death.