| Date | May 2019 | Marks available | 1 | Reference code | 19M.3.sl.TZ1.17 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Draw | Question number | 17 | Adapted from | N/A |
Question
This question is about antiviral drugs.
Oseltamivir, used for the treatment of severe flu, is inactive until converted in the liver to its active carboxylate form.
Draw a circle around the functional group that can be converted to the carboxylate by hydrolysis.
Suggest a reason for using a phosphate salt of oseltamivir in oral tablets.
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.
Markscheme
[✔]
Note: Accept circles that include the alkyl side chain.
more soluble «in water» [✔]
viruses undergo «rapid» mutation [✔]
mutation causes a change in viral protein
OR
drug to no longer binds to virus [✔]
Note: Accept “rapid reproduction «allows resistant viruses to multiply»”.
Examiners report
Many students erroneously identified the amide as the required group, failing to realise that its hydrolysis would give the carboxylate ion of the side chain lost to the drug.
About a third of the candidates realised that producing a salt would increase the drug’s aqueous solubility, though many just stated “increased bioavailability” without explaining how this came about.
Another question where well argued responses were rare, though many students gained credit for mentioning the ease of mutation and the speed of reproduction of viruses.
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.
-
17M.3.sl.TZ1.21a:
Outline how oseltamivir (Tamiflu®) works.
-
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.
