1. Enveloped viruses enter by membrane fusion, either from an internal compartment following an endocytic step, or at the cell surface. Non-enveloped viruses require some form of membrane “perforation”.
2. They are known as the human herpesviruses and are herpes simplex virus type 1, herpes simplex virus type 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human herpesvirus 6, human herpesvirus 7 and, most recently, Kaposi's Sarcoma herpesvirus.
3. HIV is called a retrovirus because it works in a back-to-front way. Unlike other viruses, retroviruses store their genetic information using RNA instead of DNA, meaning they need to 'make' DNA when they enter a human cell in order to make new copies of themselves.
4. Rhinovirus
