Acquired immune deficiency syndrome (AIDS), a disease caused by the HIV virus, has resulted in millions of deaths worldwide since it was first identified in 1981.

Explain why viral infections, such as AIDS, are generally more difficult to treat than bacterial infections.

viruses mutate quickly so adapt to drugs/evade immune system response / OWTTE;

bacteria are more complex and thus can be targeted in more ways / viruses lack sub-units/functions targeted by antibacterials / OWTTE;

different types of bacteria employ similar metabolic processes and thus can be targeted by common antibacterials / each kind of virus usually requires special drugs/approaches / OWTTE;

bacteria can be killed by interfering with cell wall production without attacking host cell / difficult to attack the virus without attacking host cell;

Option D was a popular option. The identification of the wavenumber range used in the determination of ethanol lead to many correct answers. However, why the absorption range 3200-3600 \({\text{c}}{{\text{m}}^{ - 1}}\) is not used still eludes a substantial number of candidates. How the transmission of IR radiation changes with increased levels of ethanol was not answered well, showing a poor understanding of transmittance. The question on the mild analgesic was not very well except for being able to identify the amide group in the molecules in question. The physiological effect of the drug as well as the reason for some drugs being less effective when taken orally was both very well answered. The ‘mix and split’ approach to combinatorial chemistry was generally not done well with answers that were weak showing shallow understanding.

The two structural features found in the sympathomimetic drugs were mostly correctly identified. Although many students were able to identify two chiral centers in the two structures given, not as many could identify the three needed for the mark. In the preferred method for the synthesis of optically active drugs, where many scored full marks but the difficulty of separating enantiomers due to their similar physical properties was the least popular explanation given. Surprisingly, the suggestion for increasing the aqueous solubility of an alkaline drug by adding an acid or converting it to its salt was done poorly showing a lack of understanding of acid-base chemistry and bonding.

In one argument for and one against the legalization of cannabis, while many candidates scored at least one mark out of two, some journalistic answers were seen. Description of the bonding changes that occur when the anti-cancer drug cisplatin attaches to the DNA chain was typically not well answered questions with many candidates being able to provide only one of the two ideas, usually the missing one was that \({\text{C}}{{\text{l}}^ - }\) leave \({\text{Pt/P}}{{\text{t}}^{2 + }}\). Why the trans-cisplatin is ineffective in the treatment of cancer elicited fewer correct answers than expected. Question 18 was not on AIDS per se but rather on why viral infections are more difficult to treat than bacterial infections. A significant number of students scored part marks thus illustrating shallow understanding and deserves further attention in class. Very often marks were lost due to incomplete arguments.