Oseltamivir (Tamiflu) and zanamivir (Relenza) are used against flu viruses. Explain how these drugs function.

Shikimic acid, the precursor for oseltamivir (Tamiflu), was originally extracted from star anise, and is now produced using genetically modified E. coli bacteria.

Suggest one difficulty associated with synthesizing oseltamivir (Tamiflu) from star anise.

blocks/inhibits neuraminidase/NA/«viral» enzyme which allows viruses to pass through cell membrane

prevent virus from leaving/escaping host cell «thus it cannot infect other cells»

[2 marks]

Any one of:

limited supply of star anise/plant

«star anise» takes time to grow

time-consuming/multi-step extraction

low concentration in plan

Accept “low yield for extraction/conversion” OR “requires environmentally damaging solvents”.

[1 mark]