1.3 Featues of Organisms - Viruses

Introduction

Viruses are fascinating but unique entities. They are often described as being on the border between living and non-living things. Unlike cells, viruses are not made up of cells and cannot reproduce on their own. They require a host cell to replicate.

Key Features of Viruses

The defining features of viruses are:

• Genetic Material: Viruses contain genetic material, which can be either DNA or RNA. This genetic material carries the instructions for making more viruses.
• Protein Coat (Capsid): The genetic material is enclosed within a protective protein coat called a capsid. The capsid protects the genetic material and helps the virus attach to a host cell.

Detailed Explanation of Features

Genetic Material

Viruses can have either DNA or RNA as their genetic material. This genetic material can be single-stranded or double-stranded. The type of genetic material influences how the virus replicates within a host cell.

Protein Coat (Capsid)

The capsid is made up of protein subunits called capsomeres. These capsomeres arrange themselves in a specific pattern to form the capsid. The capsid has several functions:

• Protection: It protects the viral genetic material from damage in the environment.
• Attachment: It helps the virus attach to specific receptors on the surface of a host cell.

Summary Table

Feature	Description
Genetic Material	Can be DNA or RNA (single-stranded or double-stranded). Contains the instructions for making more viruses.
Protein Coat (Capsid)	Protective outer layer made of protein subunits (capsomeres). Helps protect the genetic material and aids in attachment to host cells.

Conclusion

The combination of genetic material and a protein coat are the fundamental features that define a virus. These features are crucial for the virus's survival and ability to infect host cells.