Coronaviruses are polymorphic viruses with an outer envelope and round or oval particles, whose genetic material is single-stranded positive-stranded RNA, and whose particles have a diameter of about 60-220 nm.The viral particles are surrounded by a fatty membrane, which is covered by three types of glycoproteins, and there are a lot of spines on the outer envelope, which make the whole virus look like a corona, and these spines are in fact the glycoproteins. There are three main types of glycoproteins: the first, the spiny glycoproteins, are binding sites for receptors; the second, the small envelope glycoproteins, are envelope binding proteins; and the third, the membrane glycoproteins, are responsible for transporting nutrients from the virus. A few species also have hemagglutinin glycoproteins, and this last glycoprotein is not present in all coronaviruses; coronavirus inclusion bodies can be seen in cells infected by coronaviruses.