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 majority of viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics.