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Date May 2018 Marks available 1 Reference code 18M.3.sl.TZ1.15
Level SL Paper 3 Time zone TZ1
Command term Suggest Question number 15 Adapted from N/A

Question

Antiviral drugs are a major research focus.

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

[2]
a.

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.

[1]
b.

Markscheme

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]

a.

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]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Options » D: Medicinal chemistry » D.6 Environmental impact of some medications

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