What is the main structural difference between enveloped and nonenveloped viruses? Nonenveloped viruses have only a phospholipid membrane, whereas enveloped viruses have two membranes, the other one being a protein capsid. Enveloped viruses have their genetic material enclosed by a layer made only of protein. O Both types of viruses have a capsid and phospholipid membranes; but in the nonenveloped virus, the genetic material is between these two membranes, and in the enveloped virus, the genetic material is inside both membranes. Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane.