What do enveloped viruses possess in particular?
Enveloped viruses possess a second structural layer other than the capsid. It is often made of phospholipids and proteins from the membrane of a previous host cell, sugar or lipid structures and sometimes viral glycoproteins. Envelopes are not protective and can actually be quite particular to their environment, meaning enveloped viruses are often easier to sterilise. Envelopes also allow viruses to bind to receptor proteins on the outside of potential hosts.