A retrovirus
Human immunodeficiency virus (HIV) is a retrovirus whose genetic information is carried as RNA.
An HIV particle contains:
- RNA, carrying the viral genetic information
- reverse transcriptase, an enzyme used to make DNA from the viral RNA
- a protein capsid enclosing the internal viral material
- a lipid envelope acquired from the membrane of the helper T cell that released the virus
- attachment proteins involved in binding HIV to a host cell
Roles of the components
| Component | Relevant role |
|---|---|
| RNA | Contains the genetic information of HIV. |
| Reverse transcriptase | Produces a DNA copy from the viral RNA after infection. |
| Capsid | Forms the protein coat around the internal viral components. |
| Lipid envelope | Surrounds the virus and originates from host-cell membrane. |
| Attachment proteins | Allow the virus to bind to a host cell. |
Exam Tip: Keep RNA and reverse transcriptase distinct in structure questions. RNA carries the viral genetic information; reverse transcriptase is the enzyme used to make a DNA copy from it.