| Date | May 2017 | Marks available | 2 | Reference code | 17M.3.sl.TZ1.21 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Outline | Question number | 21 | Adapted from | N/A |
Question
Antiviral drugs are designed to take different approaches to fighting viruses.
Outline how oseltamivir (Tamiflu®) works.
Oseltamivir was commercially produced from shikimic acid, a precursor which is a metabolite in micro-organisms and plants.
Outline how green chemistry was used to develop the precursor for oseltamivir in order to overcome a shortage of the drug during the flu season.
Suggest why the administration of antibiotics to humans and animals can affect the environment.
Markscheme
«drug» blocks/inhibits «viral» enzyme/neuraminidase/NA «activity»
prevents virus from leaving/escaping host cells «thus cannot infect other cells»
[2 marks]
ALTERNATIVE 1:
«using» genetically modified/GM E. Coli/bacteria/microorganisms
E. Coli/bacteria biosynthesis
OR
E. Coli/bacteria «overfed by glucose» undergo fermentation
OR
cells of the bacteria «are broken down to» form precursor/shikimic acid
ALTERNATIVE 2:
use readily available cyclic ester/lactone
forms «the correct stereoisomer of oseltamivir» in a shorter number of chemical steps
Do not accept “planting more Chinese star anise” or “other plant sources of shikimic acid”.
[2 marks]
«can develop antibiotic» resistance in bacteria/microorganisms
OR
changes in microbial/bacterial population
Accept secondary effects, such as reduced biodiversity of aquatic/soil ecosystems, denitrification of soil (due to decline in nitrogen-fixing bacteria). No mark for just stating “water contamination”.
No mark for just stating “failure of aquatic/marine environment”.
[1 mark]
Examiners report
Syllabus sections
- 17N.3.sl.TZ0.19b: Explain how oseltamivir and zanamivir can stop the spread of the flu virus in the body.
- 16N.3.sl.TZ0.17a: Zanamivir must be taken by inhalation, not orally. Deduce what this suggests about the...
- 18N.3.sl.TZ0.15b: Outline two different ways in which antiviral medications work.
- 18N.3.hl.TZ0.19: Outline two different ways in which antiviral medications work.
-
19M.3.sl.TZ1.17a(i):
Draw a circle around the functional group that can be converted to the carboxylate by hydrolysis.
-
18M.3.sl.TZ2.19a:
Identify the names of two functional groups present in zanamivir using section 37 of the data booklet.
-
17N.3.sl.TZ0.19a:
State the names of two functional groups that both compounds contain, using section 37 of the data booklet.
-
18M.3.sl.TZ1.15a:
Oseltamivir (Tamiflu) and zanamivir (Relenza) are used against flu viruses. Explain how these drugs function.
- 19N.3.hl.TZ0.25d: Discuss two difficulties, apart from socio-economic factors, associated with finding a cure...
-
19M.3.sl.TZ2.17a:
Outline one way in which antiviral drugs work.
-
19M.3.sl.TZ1.17b:
Anti-HIV drugs, such as zidovudine, often become less effective over time.
Explain the development of resistant virus strains in the presence of antiviral drugs.
-
18N.3.sl.TZ0.15a:
State one way in which viruses differ from bacteria.
- 19N.3.sl.TZ0.18b: Discuss two difficulties, apart from socio-economic factors, associated with finding a cure...
-
19M.3.hl.TZ1.22a(i):
Draw a circle around the functional group that can be converted to the carboxylate by hydrolysis.
-
19M.3.hl.TZ2.24b:
Discuss two difficulties associated with solving the AIDS problem.
-
18M.3.sl.TZ2.19b:
Distinguish between bacteria and viruses.
-
16N.3.sl.TZ0.16b:
(i) Some antibiotic-resistant bacteria produce a beta-lactamase enzyme which destroys penicillin activity. Suggest how adding clavulanic acid to penicillin enables the antibiotic to retain its activity.
(ii) Populations of antibiotic-resistant bacteria have increased significantly over the last 60 years. Outline why antibiotics such as penicillin should not be prescribed to people suffering from a viral infection.
-
19M.3.hl.TZ1.22c:
Anti-HIV drugs, such as zidovudine, often become less effective over time.
Explain the development of resistant virus strains in the presence of antiviral drugs.
-
19M.3.hl.TZ2.24a:
Outline one way in which antiviral drugs work.
-
19N.3.sl.TZ0.18a:
State one difference between bacteria and viruses.
- 20N.3.sl.TZ0.14a(i): Name two functional groups that both zanamivir and oseltamivir contain.
-
20N.3.sl.TZ0.14a(ii):
Explain how zanamivir works as a preventative agent against flu viruses.
-
19M.3.sl.TZ2.17b:
Discuss two difficulties associated with solving the AIDS problem.
-
20N.3.hl.TZ0.19a:
Explain how zanamivir works as a preventative agent against flu viruses.
