Chapter 20, Problem 1NS.1QC

Summary Introduction

To explain:

The reason that the host specific nature of viruses preventing a global pandemic.

Introduction:

A virus is a biological enigma. It can’t be seen through the naked eyes. Viruses are made up of protein coat in which their genetic material is present. The viruses contain either double stranded or single stranded DNA or RNA as their genetic material and can evolve. These characteristic resembles the characteristic of living organisms but they can only replicate using machinery of a host cell.

Explanation of Solution

Viruses are “host specific”. They are capable of replicating within the specific living cells such as “tobacco mosaic virus” infects tobacco family of plants only and rabies virus infect mammals only. Human immunodeficiency virus (HIV) enters only specific blood cells while polio virus replicates in only nerve cells of spinal cord.

The specificity for host is determined by the molecules present in the naked capsid or envelope of the virus. These molecules bind with the specific receptor present on the outer surface of the cell. Thus, the cell that does not contain the specific receptor cannot be infected as virus cannot enter the cell. This specific nature of the virus is preventing the global pandemic.

Conclusion

Viruses are host specific they can only replicate in particular living organism thus this specific nature of viruses preventing a global pandemic.