See also. 1  Concept inventory. 2  Constructive alignment. 3  Educational assessment. 4  Ipsative assessment. 5  Norm-referenced assessment. 6  Psychometrics. 7  Standardized test.
Enveloped viruses have a lipid-based membrane surrounding the protein capsid. This envelope is partly composed of the cell membrane within which the virus replicated, and it contains proteins and carbohydrates. Some of the proteins are from the host cell and some are from the virus..
The lipid bilayer is the main fabric of the membrane, and its structure creates a semi-permeable membrane. The hydrophobic core impedes the diffusion of hydrophilic structures, such as ions and polar molecules but allows hydrophobic molecules, which can dissolve in the membrane, to cross it with ease.