1.	(a)	bacteria are self-reproducing units while viruses are not / viruses
need living hosts/cells to multiply / OWTTE;
bacteria are able to grow/metabolize/feed and excrete / viruses
lack metabolic functions;
bacteria contain various cell subunits/organelles/cell wall
(performing specific functions) / viruses consist only of genetic
material and protective coating;
bacteria are (many times) larger than viruses / viruses are
smaller than bacteria;
bacteria have more complex DNA / viruses have simpler DNA;
viruses mutate/multiply (much) faster than bacteria / bacteria
mutate/multiply slower than viruses;
If comparative term used e.g. smaller what it’s compared to is
not required.	2 max
 
(b)	alter cells genetic material so that virus cannot use it to multiply;
prevent viruses from multiplying by blocking enzyme activity
within host cell / inhibit the synthesis of viral components by
blocking enzymes inside the cell;
prevent viruses from entering (human) cell / bind to cellular
receptors targeted by viruses / bind to virus-associated proteins/
VAPs which target cellular receptors;
prevent/hinder the release of viruses from the cell;	2 max
 
(c)	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 subunits/functions targeted by antibacterials /
OWTTE;
bacteria can be killed/impaired by simple chemical agents /
viruses cannot be killed and must be targeted on genetic level / 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;	3 max
[7]

2.	HIV invades/bind to white blood cells/T4/T cells / OWTTE;
HIV viruses can mutate;
HIV viruses have similar metabolism to (human) cells/uses host cells to replicate;
high price of (antiretroviral) drugs / socioeconomic / cultural issues;	4
[4]

3.	(a)
	1
 
(b)	a chiral auxiliary is itself an enantiomer;
it is bonded to the reacting molecule to create the stereochemical conditions
necessary to follow a certain pathway;
once the desired enantiomer is formed the auxiliary is removed;
different enantiomers may have different biological effects (some of
which may be harmful);
genetic defects/deformities;	5
[6]

4.	(i)	benzene/aromatic ring/ C_6H_5 /phenyl;
Accept the circle-in-hexagon or Kekule symbols
Do not allow benzene or arene.
	amine/ NH_2 / amino;
Do not award mark if reference to secondary/tertiary given.	2
 
(ii)	to overcome the resistance that bacteria develop to existing antibiotics /
increases resistance to penicillinase enzyme / OWTTE;
Do not accept “over prescription”.
	prevents penicillinase enzyme from destroying penicillin / molecules have
different shape/stability/solubility/side-chain / OWTTE;	2
[4]

5.	(i)

any circle around the nitrogen atom / the nitrogen atom and its three
neighbouring atoms;	1
 
(ii)	tertiary;	1
 
(iii)	ester;	1
[3]

IB Questionbank Chemistry