IB Biology HL C3.2.14 Antibiotic Resistance Evolution Topic Practice

Different strains of the bacterium Enterobacter cloacae were grown on a plate and identified according to their place on the plate (for example, the first strain top left is A1). They were then transferred to Petri dishes containing agar with varying concentrations of antibiotic $\left(5,10,20,40,80,160 \mu \mathrm{gml}^{-1}\right)$.

The Petri dishes were left for 24 hours in an incubator at $25^{\circ} \mathrm{C}$ and the resulting plates are shown.