Question

The cell theory is not applicable to
A. Bacteria.
B. Algae.
C. Virus.
D. Fungi.

Answer 1

Hint: It is a biology theory called cell theory, it is the universally accepted theory and one of the most important historic scientific theory, it says that all living organisms are made up of cells, i.e. the basic structural and functional unit of all organisms, and all cells come from pre-existing cells. It only covers the living organisms.

Complete answer:
A virus is simply a protein coat surrounding a piece of DNA or RNA. Generally they can exist and adapt to the environment and infect or respond to stimulus, but they depend on the host for life cycle and do not grow and lack the basic characteristics of cells. Whereas, the bacteria, algae and fungi show the property of definite complex cellular structure and the capability to reproduce themselves without the need of the host.

Viruses are considered as neither living nor non- living entities and since viruses are not made of cells and lack cellular structures and cells are not used in their reproduction and growth, they are not considered under the cell theory.

The virus does not possess basic cellular organization as bacteria, algae and fungi. Therefore, cell theory is not applicable. Virus does not categorize or does not occur to the cell theory.

Hence, the correct answer is option (C).

Note: Bacteria, algae and fungi are the unicellular and multicellular organisms that show the complete definite cellular structure with cell organelles, produce energy by burning food and reproduce. So, all are living organisms and come under cell theory. Viruses lack all these properties of being the cellular living organism.