State the name of the causative organism (pathogen) responsible for measles.
Describe the way in which the measles pathogen is transmitted.
The measles pathogen contains a single‑stranded RNA molecule and no DNA, whereas the cells it infects contain double‑stranded DNA molecules. State two other differences between the RNA in the measles pathogen and the DNA in the infected cells.
The measles pathogen has to perform RNA replication to produce new RNA molecules for the new pathogens, and this takes place inside the infected cell. The pathogen brings its own enzyme for RNA replication but no other enzymes. Explain why the measles pathogen cannot use an enzyme from the cell to perform RNA replication.
The outer layer of the measles pathogen contains an antigen known as the H-protein. This antigen is displayed on the surface of cells infected with the measles pathogen. Describe the part played by T-lymphocytes in a primary immune response to infection by the measles pathogen.