● Viruses lack a cell structure and so are more diffi cult to target with drugs than bacteria.
● Antiviral drugs may work by altering the cell’s genetic material so that the virus cannot use it to
multiply. Alternatively, they may prevent the viruses from multiplying by blocking enzyme activity
within the host cell.

● Explanation of the different ways in which antiviral medications work.
● Description of how viruses differ from bacteria.
● Explanation of how oseltamivir (Tamiflu) and zanamivir (Relenza) work as preventative agents
against flu viruses.
● Comparison of the structures of oseltamivir and zanamivir.
● Discussion of the difficulties associated with solving the AIDS problem.
Guidance
Structures for oseltamivir and zanamivir can be found in the IB data booklet in section 37.